Context stringlengths 57 92.3k | file_name stringlengths 21 79 | start int64 14 3.67k | end int64 18 3.69k | theorem stringlengths 25 2.71k | proof stringlengths 5 10.6k |
|---|---|---|---|---|---|
import Mathlib.Topology.Separation
import Mathlib.Topology.NoetherianSpace
#align_import topology.quasi_separated from "leanprover-community/mathlib"@"5dc6092d09e5e489106865241986f7f2ad28d4c8"
open TopologicalSpace
variable {α β : Type*} [TopologicalSpace α] [TopologicalSpace β] {f : α → β}
def IsQuasiSeparated (s : Set α) : Prop :=
∀ U V : Set α, U ⊆ s → IsOpen U → IsCompact U → V ⊆ s → IsOpen V → IsCompact V → IsCompact (U ∩ V)
#align is_quasi_separated IsQuasiSeparated
@[mk_iff]
class QuasiSeparatedSpace (α : Type*) [TopologicalSpace α] : Prop where
inter_isCompact :
∀ U V : Set α, IsOpen U → IsCompact U → IsOpen V → IsCompact V → IsCompact (U ∩ V)
#align quasi_separated_space QuasiSeparatedSpace
| Mathlib/Topology/QuasiSeparated.lean | 53 | 56 | theorem isQuasiSeparated_univ_iff {α : Type*} [TopologicalSpace α] :
IsQuasiSeparated (Set.univ : Set α) ↔ QuasiSeparatedSpace α := by |
rw [quasiSeparatedSpace_iff]
simp [IsQuasiSeparated]
|
import Mathlib.Data.Complex.Basic
import Mathlib.Data.Real.Sqrt
#align_import data.complex.basic from "leanprover-community/mathlib"@"31c24aa72e7b3e5ed97a8412470e904f82b81004"
open Set ComplexConjugate
namespace Complex
theorem abs_def : (Complex.abs : ℂ → ℝ) = fun z => (normSq z).sqrt :=
rfl
#align complex.abs_def Complex.abs_def
theorem abs_apply {z : ℂ} : Complex.abs z = (normSq z).sqrt :=
rfl
#align complex.abs_apply Complex.abs_apply
@[simp, norm_cast]
theorem abs_ofReal (r : ℝ) : Complex.abs r = |r| := by
simp [Complex.abs, normSq_ofReal, Real.sqrt_mul_self_eq_abs]
#align complex.abs_of_real Complex.abs_ofReal
nonrec theorem abs_of_nonneg {r : ℝ} (h : 0 ≤ r) : Complex.abs r = r :=
(Complex.abs_ofReal _).trans (abs_of_nonneg h)
#align complex.abs_of_nonneg Complex.abs_of_nonneg
-- Porting note: removed `norm_cast` attribute because the RHS can't start with `↑`
@[simp]
theorem abs_natCast (n : ℕ) : Complex.abs n = n := Complex.abs_of_nonneg (Nat.cast_nonneg n)
#align complex.abs_of_nat Complex.abs_natCast
#align complex.abs_cast_nat Complex.abs_natCast
-- See note [no_index around OfNat.ofNat]
@[simp]
theorem abs_ofNat (n : ℕ) [n.AtLeastTwo] :
Complex.abs (no_index (OfNat.ofNat n : ℂ)) = OfNat.ofNat n :=
abs_natCast n
theorem mul_self_abs (z : ℂ) : Complex.abs z * Complex.abs z = normSq z :=
Real.mul_self_sqrt (normSq_nonneg _)
#align complex.mul_self_abs Complex.mul_self_abs
theorem sq_abs (z : ℂ) : Complex.abs z ^ 2 = normSq z :=
Real.sq_sqrt (normSq_nonneg _)
#align complex.sq_abs Complex.sq_abs
@[simp]
theorem sq_abs_sub_sq_re (z : ℂ) : Complex.abs z ^ 2 - z.re ^ 2 = z.im ^ 2 := by
rw [sq_abs, normSq_apply, ← sq, ← sq, add_sub_cancel_left]
#align complex.sq_abs_sub_sq_re Complex.sq_abs_sub_sq_re
@[simp]
theorem sq_abs_sub_sq_im (z : ℂ) : Complex.abs z ^ 2 - z.im ^ 2 = z.re ^ 2 := by
rw [← sq_abs_sub_sq_re, sub_sub_cancel]
#align complex.sq_abs_sub_sq_im Complex.sq_abs_sub_sq_im
lemma abs_add_mul_I (x y : ℝ) : abs (x + y * I) = (x ^ 2 + y ^ 2).sqrt := by
rw [← normSq_add_mul_I]; rfl
lemma abs_eq_sqrt_sq_add_sq (z : ℂ) : abs z = (z.re ^ 2 + z.im ^ 2).sqrt := by
rw [abs_apply, normSq_apply, sq, sq]
@[simp]
| Mathlib/Data/Complex/Abs.lean | 120 | 120 | theorem abs_I : Complex.abs I = 1 := by | simp [Complex.abs]
|
import Mathlib.Topology.Separation
open Set Filter
open OrderDual (toDual)
open scoped Topology
universe u v w
variable {α : Type u} {β : Type v} {γ : Type w}
class ClosedIicTopology (α : Type*) [TopologicalSpace α] [Preorder α] : Prop where
isClosed_Iic (a : α) : IsClosed (Iic a)
class ClosedIciTopology (α : Type*) [TopologicalSpace α] [Preorder α] : Prop where
isClosed_Ici (a : α) : IsClosed (Ici a)
class OrderClosedTopology (α : Type*) [TopologicalSpace α] [Preorder α] : Prop where
isClosed_le' : IsClosed { p : α × α | p.1 ≤ p.2 }
#align order_closed_topology OrderClosedTopology
instance [TopologicalSpace α] [h : FirstCountableTopology α] : FirstCountableTopology αᵒᵈ := h
instance [TopologicalSpace α] [h : SecondCountableTopology α] : SecondCountableTopology αᵒᵈ := h
theorem Dense.orderDual [TopologicalSpace α] {s : Set α} (hs : Dense s) :
Dense (OrderDual.ofDual ⁻¹' s) :=
hs
#align dense.order_dual Dense.orderDual
section ClosedIicTopology
section OrderClosedTopology
section Preorder
variable [TopologicalSpace α] [Preorder α] [t : OrderClosedTopology α]
section LinearOrder
variable [TopologicalSpace α] [LinearOrder α] [OrderClosedTopology α]
| Mathlib/Topology/Order/OrderClosed.lean | 743 | 745 | theorem isOpen_lt [TopologicalSpace β] {f g : β → α} (hf : Continuous f) (hg : Continuous g) :
IsOpen { b | f b < g b } := by |
simpa only [lt_iff_not_le] using (isClosed_le hg hf).isOpen_compl
|
import Mathlib.RingTheory.AdicCompletion.Basic
import Mathlib.RingTheory.AdicCompletion.Algebra
import Mathlib.Algebra.DirectSum.Basic
variable {R : Type*} [CommRing R] (I : Ideal R)
variable {M : Type*} [AddCommGroup M] [Module R M]
variable {N : Type*} [AddCommGroup N] [Module R N]
variable {P : Type*} [AddCommGroup P] [Module R P]
variable {T : Type*} [AddCommGroup T] [Module (AdicCompletion I R) T]
namespace AdicCompletion
open LinearMap
theorem transitionMap_comp_reduceModIdeal (f : M →ₗ[R] N) {m n : ℕ}
(hmn : m ≤ n) : transitionMap I N hmn ∘ₗ f.reduceModIdeal (I ^ n) =
(f.reduceModIdeal (I ^ m) : _ →ₗ[R] _) ∘ₗ transitionMap I M hmn := by
ext x
simp
private def adicCompletionAux (f : M →ₗ[R] N) :
AdicCompletion I M →ₗ[R] AdicCompletion I N :=
AdicCompletion.lift I (fun n ↦ reduceModIdeal (I ^ n) f ∘ₗ AdicCompletion.eval I M n)
(fun {m n} hmn ↦ by rw [← comp_assoc, AdicCompletion.transitionMap_comp_reduceModIdeal,
comp_assoc, transitionMap_comp_eval])
@[local simp]
private theorem adicCompletionAux_val_apply (f : M →ₗ[R] N) {n : ℕ} (x : AdicCompletion I M) :
(adicCompletionAux I f x).val n = f.reduceModIdeal (I ^ n) (x.val n) :=
rfl
def map (f : M →ₗ[R] N) :
AdicCompletion I M →ₗ[AdicCompletion I R] AdicCompletion I N where
toFun := adicCompletionAux I f
map_add' := by aesop
map_smul' r x := by
ext n
simp only [adicCompletionAux_val_apply, smul_eval, smul_eq_mul, RingHom.id_apply]
rw [val_smul_eq_evalₐ_smul, val_smul_eq_evalₐ_smul, map_smul]
@[simp]
theorem map_val_apply (f : M →ₗ[R] N) {n : ℕ} (x : AdicCompletion I M) :
(map I f x).val n = f.reduceModIdeal (I ^ n) (x.val n) :=
rfl
theorem map_ext {f g : AdicCompletion I M → N}
(h : ∀ (a : AdicCauchySequence I M),
f (AdicCompletion.mk I M a) = g (AdicCompletion.mk I M a)) :
f = g := by
ext x
apply induction_on I M x (fun a ↦ h a)
@[ext]
theorem map_ext' {f g : AdicCompletion I M →ₗ[AdicCompletion I R] T}
(h : ∀ (a : AdicCauchySequence I M),
f (AdicCompletion.mk I M a) = g (AdicCompletion.mk I M a)) :
f = g := by
ext x
apply induction_on I M x (fun a ↦ h a)
@[ext]
theorem map_ext'' {f g : AdicCompletion I M →ₗ[R] N}
(h : f.comp (AdicCompletion.mk I M) = g.comp (AdicCompletion.mk I M)) :
f = g := by
ext x
apply induction_on I M x (fun a ↦ LinearMap.ext_iff.mp h a)
variable (M) in
@[simp]
theorem map_id :
map I (LinearMap.id (M := M)) =
LinearMap.id (R := AdicCompletion I R) (M := AdicCompletion I M) := by
ext a n
simp
theorem map_comp (f : M →ₗ[R] N) (g : N →ₗ[R] P) :
map I g ∘ₗ map I f = map I (g ∘ₗ f) := by
ext
simp
theorem map_comp_apply (f : M →ₗ[R] N) (g : N →ₗ[R] P) (x : AdicCompletion I M) :
map I g (map I f x) = map I (g ∘ₗ f) x := by
show (map I g ∘ₗ map I f) x = map I (g ∘ₗ f) x
rw [map_comp]
@[simp]
theorem map_mk (f : M →ₗ[R] N) (a : AdicCauchySequence I M) :
map I f (AdicCompletion.mk I M a) =
AdicCompletion.mk I N (AdicCauchySequence.map I f a) :=
rfl
@[simp]
theorem val_sum {α : Type*} (s : Finset α) (f : α → AdicCompletion I M) (n : ℕ) :
(Finset.sum s f).val n = Finset.sum s (fun a ↦ (f a).val n) := by
change (Submodule.subtype (AdicCompletion.submodule I M) _) n = _
rw [map_sum, Finset.sum_apply, Submodule.coeSubtype]
def congr (f : M ≃ₗ[R] N) :
AdicCompletion I M ≃ₗ[AdicCompletion I R] AdicCompletion I N :=
LinearEquiv.ofLinear (map I f)
(map I f.symm) (by simp [map_comp]) (by simp [map_comp])
@[simp]
theorem congr_apply (f : M ≃ₗ[R] N) (x : AdicCompletion I M) :
congr I f x = map I f x :=
rfl
@[simp]
theorem congr_symm_apply (f : M ≃ₗ[R] N) (x : AdicCompletion I N) :
(congr I f).symm x = map I f.symm x :=
rfl
section Families
variable {ι : Type*} [DecidableEq ι] (M : ι → Type*) [∀ i, AddCommGroup (M i)]
[∀ i, Module R (M i)]
section Sum
open DirectSum
def sum :
(⨁ j, (AdicCompletion I (M j))) →ₗ[AdicCompletion I R] AdicCompletion I (⨁ j, M j) :=
toModule (AdicCompletion I R) ι (AdicCompletion I (⨁ j, M j))
(fun j ↦ map I (lof R ι M j))
@[simp]
theorem sum_lof (j : ι) (x : AdicCompletion I (M j)) :
sum I M ((DirectSum.lof (AdicCompletion I R) ι (fun i ↦ AdicCompletion I (M i)) j) x) =
map I (lof R ι M j) x := by
simp [sum]
@[simp]
theorem sum_of (j : ι) (x : AdicCompletion I (M j)) :
sum I M ((DirectSum.of (fun i ↦ AdicCompletion I (M i)) j) x) =
map I (lof R ι M j) x := by
rw [← lof_eq_of R]
apply sum_lof
variable [Fintype ι]
def sumInv : AdicCompletion I (⨁ j, M j) →ₗ[AdicCompletion I R] (⨁ j, (AdicCompletion I (M j))) :=
letI f := map I (linearEquivFunOnFintype R ι M)
letI g := linearEquivFunOnFintype (AdicCompletion I R) ι (fun j ↦ AdicCompletion I (M j))
g.symm.toLinearMap ∘ₗ pi I M ∘ₗ f
@[simp]
theorem component_sumInv (x : AdicCompletion I (⨁ j, M j)) (j : ι) :
component (AdicCompletion I R) ι _ j (sumInv I M x) =
map I (component R ι _ j) x := by
apply induction_on I _ x (fun x ↦ ?_)
rfl
@[simp]
| Mathlib/RingTheory/AdicCompletion/Functoriality.lean | 277 | 280 | theorem sumInv_apply (x : AdicCompletion I (⨁ j, M j)) (j : ι) :
(sumInv I M x) j = map I (component R ι _ j) x := by |
apply induction_on I _ x (fun x ↦ ?_)
rfl
|
import Mathlib.Algebra.GroupWithZero.Divisibility
import Mathlib.Algebra.Order.Group.Int
import Mathlib.Algebra.Order.Ring.Nat
import Mathlib.Algebra.Ring.Rat
import Mathlib.Data.PNat.Defs
#align_import data.rat.lemmas from "leanprover-community/mathlib"@"550b58538991c8977703fdeb7c9d51a5aa27df11"
namespace Rat
open Rat
theorem num_dvd (a) {b : ℤ} (b0 : b ≠ 0) : (a /. b).num ∣ a := by
cases' e : a /. b with n d h c
rw [Rat.mk'_eq_divInt, divInt_eq_iff b0 (mod_cast h)] at e
refine Int.natAbs_dvd.1 <| Int.dvd_natAbs.1 <| Int.natCast_dvd_natCast.2 <|
c.dvd_of_dvd_mul_right ?_
have := congr_arg Int.natAbs e
simp only [Int.natAbs_mul, Int.natAbs_ofNat] at this; simp [this]
#align rat.num_dvd Rat.num_dvd
theorem den_dvd (a b : ℤ) : ((a /. b).den : ℤ) ∣ b := by
by_cases b0 : b = 0; · simp [b0]
cases' e : a /. b with n d h c
rw [mk'_eq_divInt, divInt_eq_iff b0 (ne_of_gt (Int.natCast_pos.2 (Nat.pos_of_ne_zero h)))] at e
refine Int.dvd_natAbs.1 <| Int.natCast_dvd_natCast.2 <| c.symm.dvd_of_dvd_mul_left ?_
rw [← Int.natAbs_mul, ← Int.natCast_dvd_natCast, Int.dvd_natAbs, ← e]; simp
#align rat.denom_dvd Rat.den_dvd
theorem num_den_mk {q : ℚ} {n d : ℤ} (hd : d ≠ 0) (qdf : q = n /. d) :
∃ c : ℤ, n = c * q.num ∧ d = c * q.den := by
obtain rfl | hn := eq_or_ne n 0
· simp [qdf]
have : q.num * d = n * ↑q.den := by
refine (divInt_eq_iff ?_ hd).mp ?_
· exact Int.natCast_ne_zero.mpr (Rat.den_nz _)
· rwa [num_divInt_den]
have hqdn : q.num ∣ n := by
rw [qdf]
exact Rat.num_dvd _ hd
refine ⟨n / q.num, ?_, ?_⟩
· rw [Int.ediv_mul_cancel hqdn]
· refine Int.eq_mul_div_of_mul_eq_mul_of_dvd_left ?_ hqdn this
rw [qdf]
exact Rat.num_ne_zero.2 ((divInt_ne_zero hd).mpr hn)
#align rat.num_denom_mk Rat.num_den_mk
#noalign rat.mk_pnat_num
#noalign rat.mk_pnat_denom
theorem num_mk (n d : ℤ) : (n /. d).num = d.sign * n / n.gcd d := by
have (m : ℕ) : Int.natAbs (m + 1) = m + 1 := by
rw [← Nat.cast_one, ← Nat.cast_add, Int.natAbs_cast]
rcases d with ((_ | _) | _) <;>
rw [← Int.div_eq_ediv_of_dvd] <;>
simp [divInt, mkRat, Rat.normalize, Nat.succPNat, Int.sign, Int.gcd,
Int.zero_ediv, Int.ofNat_dvd_left, Nat.gcd_dvd_left, this]
#align rat.num_mk Rat.num_mk
theorem den_mk (n d : ℤ) : (n /. d).den = if d = 0 then 1 else d.natAbs / n.gcd d := by
have (m : ℕ) : Int.natAbs (m + 1) = m + 1 := by
rw [← Nat.cast_one, ← Nat.cast_add, Int.natAbs_cast]
rcases d with ((_ | _) | _) <;>
simp [divInt, mkRat, Rat.normalize, Nat.succPNat, Int.sign, Int.gcd,
if_neg (Nat.cast_add_one_ne_zero _), this]
#align rat.denom_mk Rat.den_mk
#noalign rat.mk_pnat_denom_dvd
theorem add_den_dvd (q₁ q₂ : ℚ) : (q₁ + q₂).den ∣ q₁.den * q₂.den := by
rw [add_def, normalize_eq]
apply Nat.div_dvd_of_dvd
apply Nat.gcd_dvd_right
#align rat.add_denom_dvd Rat.add_den_dvd
theorem mul_den_dvd (q₁ q₂ : ℚ) : (q₁ * q₂).den ∣ q₁.den * q₂.den := by
rw [mul_def, normalize_eq]
apply Nat.div_dvd_of_dvd
apply Nat.gcd_dvd_right
#align rat.mul_denom_dvd Rat.mul_den_dvd
theorem mul_num (q₁ q₂ : ℚ) :
(q₁ * q₂).num = q₁.num * q₂.num / Nat.gcd (q₁.num * q₂.num).natAbs (q₁.den * q₂.den) := by
rw [mul_def, normalize_eq]
#align rat.mul_num Rat.mul_num
theorem mul_den (q₁ q₂ : ℚ) :
(q₁ * q₂).den =
q₁.den * q₂.den / Nat.gcd (q₁.num * q₂.num).natAbs (q₁.den * q₂.den) := by
rw [mul_def, normalize_eq]
#align rat.mul_denom Rat.mul_den
theorem mul_self_num (q : ℚ) : (q * q).num = q.num * q.num := by
rw [mul_num, Int.natAbs_mul, Nat.Coprime.gcd_eq_one, Int.ofNat_one, Int.ediv_one]
exact (q.reduced.mul_right q.reduced).mul (q.reduced.mul_right q.reduced)
#align rat.mul_self_num Rat.mul_self_num
| Mathlib/Data/Rat/Lemmas.lean | 109 | 111 | theorem mul_self_den (q : ℚ) : (q * q).den = q.den * q.den := by |
rw [Rat.mul_den, Int.natAbs_mul, Nat.Coprime.gcd_eq_one, Nat.div_one]
exact (q.reduced.mul_right q.reduced).mul (q.reduced.mul_right q.reduced)
|
import Mathlib.CategoryTheory.Category.Cat
import Mathlib.CategoryTheory.Elements
#align_import category_theory.grothendieck from "leanprover-community/mathlib"@"14b69e9f3c16630440a2cbd46f1ddad0d561dee7"
universe u
namespace CategoryTheory
variable {C D : Type*} [Category C] [Category D]
variable (F : C ⥤ Cat)
-- Porting note(#5171): no such linter yet
-- @[nolint has_nonempty_instance]
structure Grothendieck where
base : C
fiber : F.obj base
#align category_theory.grothendieck CategoryTheory.Grothendieck
namespace Grothendieck
variable {F}
structure Hom (X Y : Grothendieck F) where
base : X.base ⟶ Y.base
fiber : (F.map base).obj X.fiber ⟶ Y.fiber
#align category_theory.grothendieck.hom CategoryTheory.Grothendieck.Hom
@[ext]
| Mathlib/CategoryTheory/Grothendieck.lean | 78 | 83 | theorem ext {X Y : Grothendieck F} (f g : Hom X Y) (w_base : f.base = g.base)
(w_fiber : eqToHom (by rw [w_base]) ≫ f.fiber = g.fiber) : f = g := by |
cases f; cases g
congr
dsimp at w_base
aesop_cat
|
import Mathlib.CategoryTheory.Adjunction.Basic
import Mathlib.CategoryTheory.Category.Preorder
import Mathlib.CategoryTheory.IsomorphismClasses
import Mathlib.CategoryTheory.Thin
#align_import category_theory.skeletal from "leanprover-community/mathlib"@"28aa996fc6fb4317f0083c4e6daf79878d81be33"
universe v₁ v₂ v₃ u₁ u₂ u₃
namespace CategoryTheory
open Category
variable (C : Type u₁) [Category.{v₁} C]
variable (D : Type u₂) [Category.{v₂} D]
variable {E : Type u₃} [Category.{v₃} E]
def Skeletal : Prop :=
∀ ⦃X Y : C⦄, IsIsomorphic X Y → X = Y
#align category_theory.skeletal CategoryTheory.Skeletal
structure IsSkeletonOf (F : D ⥤ C) : Prop where
skel : Skeletal D
eqv : F.IsEquivalence := by infer_instance
#align category_theory.is_skeleton_of CategoryTheory.IsSkeletonOf
attribute [local instance] isIsomorphicSetoid
variable {C D}
theorem Functor.eq_of_iso {F₁ F₂ : D ⥤ C} [Quiver.IsThin C] (hC : Skeletal C) (hF : F₁ ≅ F₂) :
F₁ = F₂ :=
Functor.ext (fun X => hC ⟨hF.app X⟩) fun _ _ _ => Subsingleton.elim _ _
#align category_theory.functor.eq_of_iso CategoryTheory.Functor.eq_of_iso
theorem functor_skeletal [Quiver.IsThin C] (hC : Skeletal C) : Skeletal (D ⥤ C) := fun _ _ h =>
h.elim (Functor.eq_of_iso hC)
#align category_theory.functor_skeletal CategoryTheory.functor_skeletal
variable (C D)
def Skeleton : Type u₁ := InducedCategory C Quotient.out
#align category_theory.skeleton CategoryTheory.Skeleton
instance [Inhabited C] : Inhabited (Skeleton C) :=
⟨⟦default⟧⟩
-- Porting note: previously `Skeleton` used `deriving Category`
noncomputable instance : Category (Skeleton C) := by
apply InducedCategory.category
@[simps!]
noncomputable def fromSkeleton : Skeleton C ⥤ C :=
inducedFunctor _
#align category_theory.from_skeleton CategoryTheory.fromSkeleton
-- Porting note: previously `fromSkeleton` used `deriving Faithful, Full`
noncomputable instance : (fromSkeleton C).Full := by
apply InducedCategory.full
noncomputable instance : (fromSkeleton C).Faithful := by
apply InducedCategory.faithful
instance : (fromSkeleton C).EssSurj where mem_essImage X := ⟨Quotient.mk' X, Quotient.mk_out X⟩
-- Porting note: named this instance
noncomputable instance fromSkeleton.isEquivalence : (fromSkeleton C).IsEquivalence where
noncomputable def skeletonEquivalence : Skeleton C ≌ C :=
(fromSkeleton C).asEquivalence
#align category_theory.skeleton_equivalence CategoryTheory.skeletonEquivalence
| Mathlib/CategoryTheory/Skeletal.lean | 108 | 111 | theorem skeleton_skeletal : Skeletal (Skeleton C) := by |
rintro X Y ⟨h⟩
have : X.out ≈ Y.out := ⟨(fromSkeleton C).mapIso h⟩
simpa using Quotient.sound this
|
import Mathlib.Algebra.BigOperators.Fin
import Mathlib.Algebra.Polynomial.Degree.Lemmas
#align_import data.polynomial.erase_lead from "leanprover-community/mathlib"@"fa256f00ce018e7b40e1dc756e403c86680bf448"
noncomputable section
open Polynomial
open Polynomial Finset
namespace Polynomial
variable {R : Type*} [Semiring R] {f : R[X]}
def eraseLead (f : R[X]) : R[X] :=
Polynomial.erase f.natDegree f
#align polynomial.erase_lead Polynomial.eraseLead
section EraseLead
theorem eraseLead_support (f : R[X]) : f.eraseLead.support = f.support.erase f.natDegree := by
simp only [eraseLead, support_erase]
#align polynomial.erase_lead_support Polynomial.eraseLead_support
theorem eraseLead_coeff (i : ℕ) :
f.eraseLead.coeff i = if i = f.natDegree then 0 else f.coeff i := by
simp only [eraseLead, coeff_erase]
#align polynomial.erase_lead_coeff Polynomial.eraseLead_coeff
@[simp]
theorem eraseLead_coeff_natDegree : f.eraseLead.coeff f.natDegree = 0 := by simp [eraseLead_coeff]
#align polynomial.erase_lead_coeff_nat_degree Polynomial.eraseLead_coeff_natDegree
| Mathlib/Algebra/Polynomial/EraseLead.lean | 55 | 56 | theorem eraseLead_coeff_of_ne (i : ℕ) (hi : i ≠ f.natDegree) : f.eraseLead.coeff i = f.coeff i := by |
simp [eraseLead_coeff, hi]
|
import Mathlib.Algebra.Group.Indicator
import Mathlib.Data.Finset.Piecewise
import Mathlib.Data.Finset.Preimage
#align_import algebra.big_operators.basic from "leanprover-community/mathlib"@"65a1391a0106c9204fe45bc73a039f056558cb83"
-- TODO
-- assert_not_exists AddCommMonoidWithOne
assert_not_exists MonoidWithZero
assert_not_exists MulAction
variable {ι κ α β γ : Type*}
open Fin Function
library_note "operator precedence of big operators"
@[to_additive (attr := simp)]
theorem map_prod [CommMonoid β] [CommMonoid γ] {G : Type*} [FunLike G β γ] [MonoidHomClass G β γ]
(g : G) (f : α → β) (s : Finset α) : g (∏ x ∈ s, f x) = ∏ x ∈ s, g (f x) := by
simp only [Finset.prod_eq_multiset_prod, map_multiset_prod, Multiset.map_map]; rfl
#align map_prod map_prod
#align map_sum map_sum
@[to_additive]
theorem MonoidHom.coe_finset_prod [MulOneClass β] [CommMonoid γ] (f : α → β →* γ) (s : Finset α) :
⇑(∏ x ∈ s, f x) = ∏ x ∈ s, ⇑(f x) :=
map_prod (MonoidHom.coeFn β γ) _ _
#align monoid_hom.coe_finset_prod MonoidHom.coe_finset_prod
#align add_monoid_hom.coe_finset_sum AddMonoidHom.coe_finset_sum
@[to_additive (attr := simp)
"See also `Finset.sum_apply`, with the same conclusion but with the weaker hypothesis
`f : α → β → γ`"]
theorem MonoidHom.finset_prod_apply [MulOneClass β] [CommMonoid γ] (f : α → β →* γ) (s : Finset α)
(b : β) : (∏ x ∈ s, f x) b = ∏ x ∈ s, f x b :=
map_prod (MonoidHom.eval b) _ _
#align monoid_hom.finset_prod_apply MonoidHom.finset_prod_apply
#align add_monoid_hom.finset_sum_apply AddMonoidHom.finset_sum_apply
variable {s s₁ s₂ : Finset α} {a : α} {f g : α → β}
namespace Finset
section CommMonoid
variable [CommMonoid β]
@[to_additive (attr := simp)]
theorem prod_empty : ∏ x ∈ ∅, f x = 1 :=
rfl
#align finset.prod_empty Finset.prod_empty
#align finset.sum_empty Finset.sum_empty
@[to_additive]
theorem prod_of_empty [IsEmpty α] (s : Finset α) : ∏ i ∈ s, f i = 1 := by
rw [eq_empty_of_isEmpty s, prod_empty]
#align finset.prod_of_empty Finset.prod_of_empty
#align finset.sum_of_empty Finset.sum_of_empty
@[to_additive (attr := simp)]
theorem prod_cons (h : a ∉ s) : ∏ x ∈ cons a s h, f x = f a * ∏ x ∈ s, f x :=
fold_cons h
#align finset.prod_cons Finset.prod_cons
#align finset.sum_cons Finset.sum_cons
@[to_additive (attr := simp)]
theorem prod_insert [DecidableEq α] : a ∉ s → ∏ x ∈ insert a s, f x = f a * ∏ x ∈ s, f x :=
fold_insert
#align finset.prod_insert Finset.prod_insert
#align finset.sum_insert Finset.sum_insert
@[to_additive (attr := simp) "The sum of `f` over `insert a s` is the same as
the sum over `s`, as long as `a` is in `s` or `f a = 0`."]
theorem prod_insert_of_eq_one_if_not_mem [DecidableEq α] (h : a ∉ s → f a = 1) :
∏ x ∈ insert a s, f x = ∏ x ∈ s, f x := by
by_cases hm : a ∈ s
· simp_rw [insert_eq_of_mem hm]
· rw [prod_insert hm, h hm, one_mul]
#align finset.prod_insert_of_eq_one_if_not_mem Finset.prod_insert_of_eq_one_if_not_mem
#align finset.sum_insert_of_eq_zero_if_not_mem Finset.sum_insert_of_eq_zero_if_not_mem
@[to_additive (attr := simp) "The sum of `f` over `insert a s` is the same as
the sum over `s`, as long as `f a = 0`."]
theorem prod_insert_one [DecidableEq α] (h : f a = 1) : ∏ x ∈ insert a s, f x = ∏ x ∈ s, f x :=
prod_insert_of_eq_one_if_not_mem fun _ => h
#align finset.prod_insert_one Finset.prod_insert_one
#align finset.sum_insert_zero Finset.sum_insert_zero
@[to_additive]
theorem prod_insert_div {M : Type*} [CommGroup M] [DecidableEq α] (ha : a ∉ s) {f : α → M} :
(∏ x ∈ insert a s, f x) / f a = ∏ x ∈ s, f x := by simp [ha]
@[to_additive (attr := simp)]
theorem prod_singleton (f : α → β) (a : α) : ∏ x ∈ singleton a, f x = f a :=
Eq.trans fold_singleton <| mul_one _
#align finset.prod_singleton Finset.prod_singleton
#align finset.sum_singleton Finset.sum_singleton
@[to_additive]
theorem prod_pair [DecidableEq α] {a b : α} (h : a ≠ b) :
(∏ x ∈ ({a, b} : Finset α), f x) = f a * f b := by
rw [prod_insert (not_mem_singleton.2 h), prod_singleton]
#align finset.prod_pair Finset.prod_pair
#align finset.sum_pair Finset.sum_pair
@[to_additive (attr := simp)]
theorem prod_const_one : (∏ _x ∈ s, (1 : β)) = 1 := by
simp only [Finset.prod, Multiset.map_const', Multiset.prod_replicate, one_pow]
#align finset.prod_const_one Finset.prod_const_one
#align finset.sum_const_zero Finset.sum_const_zero
@[to_additive (attr := simp)]
theorem prod_image [DecidableEq α] {s : Finset γ} {g : γ → α} :
(∀ x ∈ s, ∀ y ∈ s, g x = g y → x = y) → ∏ x ∈ s.image g, f x = ∏ x ∈ s, f (g x) :=
fold_image
#align finset.prod_image Finset.prod_image
#align finset.sum_image Finset.sum_image
@[to_additive (attr := simp)]
theorem prod_map (s : Finset α) (e : α ↪ γ) (f : γ → β) :
∏ x ∈ s.map e, f x = ∏ x ∈ s, f (e x) := by
rw [Finset.prod, Finset.map_val, Multiset.map_map]; rfl
#align finset.prod_map Finset.prod_map
#align finset.sum_map Finset.sum_map
@[to_additive]
lemma prod_attach (s : Finset α) (f : α → β) : ∏ x ∈ s.attach, f x = ∏ x ∈ s, f x := by
classical rw [← prod_image Subtype.coe_injective.injOn, attach_image_val]
#align finset.prod_attach Finset.prod_attach
#align finset.sum_attach Finset.sum_attach
@[to_additive (attr := congr)]
theorem prod_congr (h : s₁ = s₂) : (∀ x ∈ s₂, f x = g x) → s₁.prod f = s₂.prod g := by
rw [h]; exact fold_congr
#align finset.prod_congr Finset.prod_congr
#align finset.sum_congr Finset.sum_congr
@[to_additive]
theorem prod_eq_one {f : α → β} {s : Finset α} (h : ∀ x ∈ s, f x = 1) : ∏ x ∈ s, f x = 1 :=
calc
∏ x ∈ s, f x = ∏ _x ∈ s, 1 := Finset.prod_congr rfl h
_ = 1 := Finset.prod_const_one
#align finset.prod_eq_one Finset.prod_eq_one
#align finset.sum_eq_zero Finset.sum_eq_zero
@[to_additive]
theorem prod_disjUnion (h) :
∏ x ∈ s₁.disjUnion s₂ h, f x = (∏ x ∈ s₁, f x) * ∏ x ∈ s₂, f x := by
refine Eq.trans ?_ (fold_disjUnion h)
rw [one_mul]
rfl
#align finset.prod_disj_union Finset.prod_disjUnion
#align finset.sum_disj_union Finset.sum_disjUnion
@[to_additive]
theorem prod_disjiUnion (s : Finset ι) (t : ι → Finset α) (h) :
∏ x ∈ s.disjiUnion t h, f x = ∏ i ∈ s, ∏ x ∈ t i, f x := by
refine Eq.trans ?_ (fold_disjiUnion h)
dsimp [Finset.prod, Multiset.prod, Multiset.fold, Finset.disjUnion, Finset.fold]
congr
exact prod_const_one.symm
#align finset.prod_disj_Union Finset.prod_disjiUnion
#align finset.sum_disj_Union Finset.sum_disjiUnion
@[to_additive]
theorem prod_union_inter [DecidableEq α] :
(∏ x ∈ s₁ ∪ s₂, f x) * ∏ x ∈ s₁ ∩ s₂, f x = (∏ x ∈ s₁, f x) * ∏ x ∈ s₂, f x :=
fold_union_inter
#align finset.prod_union_inter Finset.prod_union_inter
#align finset.sum_union_inter Finset.sum_union_inter
@[to_additive]
theorem prod_union [DecidableEq α] (h : Disjoint s₁ s₂) :
∏ x ∈ s₁ ∪ s₂, f x = (∏ x ∈ s₁, f x) * ∏ x ∈ s₂, f x := by
rw [← prod_union_inter, disjoint_iff_inter_eq_empty.mp h]; exact (mul_one _).symm
#align finset.prod_union Finset.prod_union
#align finset.sum_union Finset.sum_union
@[to_additive]
theorem prod_filter_mul_prod_filter_not
(s : Finset α) (p : α → Prop) [DecidablePred p] [∀ x, Decidable (¬p x)] (f : α → β) :
(∏ x ∈ s.filter p, f x) * ∏ x ∈ s.filter fun x => ¬p x, f x = ∏ x ∈ s, f x := by
have := Classical.decEq α
rw [← prod_union (disjoint_filter_filter_neg s s p), filter_union_filter_neg_eq]
#align finset.prod_filter_mul_prod_filter_not Finset.prod_filter_mul_prod_filter_not
#align finset.sum_filter_add_sum_filter_not Finset.sum_filter_add_sum_filter_not
section
open Finset
variable [Fintype α] [CommMonoid β]
@[to_additive]
theorem IsCompl.prod_mul_prod {s t : Finset α} (h : IsCompl s t) (f : α → β) :
(∏ i ∈ s, f i) * ∏ i ∈ t, f i = ∏ i, f i :=
(Finset.prod_disjUnion h.disjoint).symm.trans <| by
classical rw [Finset.disjUnion_eq_union, ← Finset.sup_eq_union, h.sup_eq_top]; rfl
#align is_compl.prod_mul_prod IsCompl.prod_mul_prod
#align is_compl.sum_add_sum IsCompl.sum_add_sum
end
namespace Finset
section CommMonoid
variable [CommMonoid β]
@[to_additive "Adding the sums of a function over `s` and over `sᶜ` gives the whole sum.
For a version expressed with subtypes, see `Fintype.sum_subtype_add_sum_subtype`. "]
theorem prod_mul_prod_compl [Fintype α] [DecidableEq α] (s : Finset α) (f : α → β) :
(∏ i ∈ s, f i) * ∏ i ∈ sᶜ, f i = ∏ i, f i :=
IsCompl.prod_mul_prod isCompl_compl f
#align finset.prod_mul_prod_compl Finset.prod_mul_prod_compl
#align finset.sum_add_sum_compl Finset.sum_add_sum_compl
@[to_additive]
theorem prod_compl_mul_prod [Fintype α] [DecidableEq α] (s : Finset α) (f : α → β) :
(∏ i ∈ sᶜ, f i) * ∏ i ∈ s, f i = ∏ i, f i :=
(@isCompl_compl _ s _).symm.prod_mul_prod f
#align finset.prod_compl_mul_prod Finset.prod_compl_mul_prod
#align finset.sum_compl_add_sum Finset.sum_compl_add_sum
@[to_additive]
theorem prod_sdiff [DecidableEq α] (h : s₁ ⊆ s₂) :
(∏ x ∈ s₂ \ s₁, f x) * ∏ x ∈ s₁, f x = ∏ x ∈ s₂, f x := by
rw [← prod_union sdiff_disjoint, sdiff_union_of_subset h]
#align finset.prod_sdiff Finset.prod_sdiff
#align finset.sum_sdiff Finset.sum_sdiff
@[to_additive]
theorem prod_subset_one_on_sdiff [DecidableEq α] (h : s₁ ⊆ s₂) (hg : ∀ x ∈ s₂ \ s₁, g x = 1)
(hfg : ∀ x ∈ s₁, f x = g x) : ∏ i ∈ s₁, f i = ∏ i ∈ s₂, g i := by
rw [← prod_sdiff h, prod_eq_one hg, one_mul]
exact prod_congr rfl hfg
#align finset.prod_subset_one_on_sdiff Finset.prod_subset_one_on_sdiff
#align finset.sum_subset_zero_on_sdiff Finset.sum_subset_zero_on_sdiff
@[to_additive]
theorem prod_subset (h : s₁ ⊆ s₂) (hf : ∀ x ∈ s₂, x ∉ s₁ → f x = 1) :
∏ x ∈ s₁, f x = ∏ x ∈ s₂, f x :=
haveI := Classical.decEq α
prod_subset_one_on_sdiff h (by simpa) fun _ _ => rfl
#align finset.prod_subset Finset.prod_subset
#align finset.sum_subset Finset.sum_subset
@[to_additive (attr := simp)]
theorem prod_disj_sum (s : Finset α) (t : Finset γ) (f : Sum α γ → β) :
∏ x ∈ s.disjSum t, f x = (∏ x ∈ s, f (Sum.inl x)) * ∏ x ∈ t, f (Sum.inr x) := by
rw [← map_inl_disjUnion_map_inr, prod_disjUnion, prod_map, prod_map]
rfl
#align finset.prod_disj_sum Finset.prod_disj_sum
#align finset.sum_disj_sum Finset.sum_disj_sum
@[to_additive]
theorem prod_sum_elim (s : Finset α) (t : Finset γ) (f : α → β) (g : γ → β) :
∏ x ∈ s.disjSum t, Sum.elim f g x = (∏ x ∈ s, f x) * ∏ x ∈ t, g x := by simp
#align finset.prod_sum_elim Finset.prod_sum_elim
#align finset.sum_sum_elim Finset.sum_sum_elim
@[to_additive]
theorem prod_biUnion [DecidableEq α] {s : Finset γ} {t : γ → Finset α}
(hs : Set.PairwiseDisjoint (↑s) t) : ∏ x ∈ s.biUnion t, f x = ∏ x ∈ s, ∏ i ∈ t x, f i := by
rw [← disjiUnion_eq_biUnion _ _ hs, prod_disjiUnion]
#align finset.prod_bUnion Finset.prod_biUnion
#align finset.sum_bUnion Finset.sum_biUnion
@[to_additive "Sum over a sigma type equals the sum of fiberwise sums. For rewriting
in the reverse direction, use `Finset.sum_sigma'`"]
theorem prod_sigma {σ : α → Type*} (s : Finset α) (t : ∀ a, Finset (σ a)) (f : Sigma σ → β) :
∏ x ∈ s.sigma t, f x = ∏ a ∈ s, ∏ s ∈ t a, f ⟨a, s⟩ := by
simp_rw [← disjiUnion_map_sigma_mk, prod_disjiUnion, prod_map, Function.Embedding.sigmaMk_apply]
#align finset.prod_sigma Finset.prod_sigma
#align finset.sum_sigma Finset.sum_sigma
@[to_additive]
theorem prod_sigma' {σ : α → Type*} (s : Finset α) (t : ∀ a, Finset (σ a)) (f : ∀ a, σ a → β) :
(∏ a ∈ s, ∏ s ∈ t a, f a s) = ∏ x ∈ s.sigma t, f x.1 x.2 :=
Eq.symm <| prod_sigma s t fun x => f x.1 x.2
#align finset.prod_sigma' Finset.prod_sigma'
#align finset.sum_sigma' Finset.sum_sigma'
@[to_additive "Taking a sum over `univ.pi t` is the same as taking the sum over
`Fintype.piFinset t`. `univ.pi t` and `Fintype.piFinset t` are essentially the same `Finset`,
but differ in the type of their element, `univ.pi t` is a `Finset (Π a ∈ univ, t a)` and
`Fintype.piFinset t` is a `Finset (Π a, t a)`."]
lemma prod_univ_pi [DecidableEq ι] [Fintype ι] {κ : ι → Type*} (t : ∀ i, Finset (κ i))
(f : (∀ i ∈ (univ : Finset ι), κ i) → β) :
∏ x ∈ univ.pi t, f x = ∏ x ∈ Fintype.piFinset t, f fun a _ ↦ x a := by
apply prod_nbij' (fun x i ↦ x i $ mem_univ _) (fun x i _ ↦ x i) <;> simp
#align finset.prod_univ_pi Finset.prod_univ_pi
#align finset.sum_univ_pi Finset.sum_univ_pi
@[to_additive (attr := simp)]
lemma prod_diag [DecidableEq α] (s : Finset α) (f : α × α → β) :
∏ i ∈ s.diag, f i = ∏ i ∈ s, f (i, i) := by
apply prod_nbij' Prod.fst (fun i ↦ (i, i)) <;> simp
@[to_additive]
theorem prod_finset_product (r : Finset (γ × α)) (s : Finset γ) (t : γ → Finset α)
(h : ∀ p : γ × α, p ∈ r ↔ p.1 ∈ s ∧ p.2 ∈ t p.1) {f : γ × α → β} :
∏ p ∈ r, f p = ∏ c ∈ s, ∏ a ∈ t c, f (c, a) := by
refine Eq.trans ?_ (prod_sigma s t fun p => f (p.1, p.2))
apply prod_equiv (Equiv.sigmaEquivProd _ _).symm <;> simp [h]
#align finset.prod_finset_product Finset.prod_finset_product
#align finset.sum_finset_product Finset.sum_finset_product
@[to_additive]
theorem prod_finset_product' (r : Finset (γ × α)) (s : Finset γ) (t : γ → Finset α)
(h : ∀ p : γ × α, p ∈ r ↔ p.1 ∈ s ∧ p.2 ∈ t p.1) {f : γ → α → β} :
∏ p ∈ r, f p.1 p.2 = ∏ c ∈ s, ∏ a ∈ t c, f c a :=
prod_finset_product r s t h
#align finset.prod_finset_product' Finset.prod_finset_product'
#align finset.sum_finset_product' Finset.sum_finset_product'
@[to_additive]
theorem prod_finset_product_right (r : Finset (α × γ)) (s : Finset γ) (t : γ → Finset α)
(h : ∀ p : α × γ, p ∈ r ↔ p.2 ∈ s ∧ p.1 ∈ t p.2) {f : α × γ → β} :
∏ p ∈ r, f p = ∏ c ∈ s, ∏ a ∈ t c, f (a, c) := by
refine Eq.trans ?_ (prod_sigma s t fun p => f (p.2, p.1))
apply prod_equiv ((Equiv.prodComm _ _).trans (Equiv.sigmaEquivProd _ _).symm) <;> simp [h]
#align finset.prod_finset_product_right Finset.prod_finset_product_right
#align finset.sum_finset_product_right Finset.sum_finset_product_right
@[to_additive]
theorem prod_finset_product_right' (r : Finset (α × γ)) (s : Finset γ) (t : γ → Finset α)
(h : ∀ p : α × γ, p ∈ r ↔ p.2 ∈ s ∧ p.1 ∈ t p.2) {f : α → γ → β} :
∏ p ∈ r, f p.1 p.2 = ∏ c ∈ s, ∏ a ∈ t c, f a c :=
prod_finset_product_right r s t h
#align finset.prod_finset_product_right' Finset.prod_finset_product_right'
#align finset.sum_finset_product_right' Finset.sum_finset_product_right'
@[to_additive]
theorem prod_image' [DecidableEq α] {s : Finset γ} {g : γ → α} (h : γ → β)
(eq : ∀ c ∈ s, f (g c) = ∏ x ∈ s.filter fun c' => g c' = g c, h x) :
∏ x ∈ s.image g, f x = ∏ x ∈ s, h x :=
calc
∏ x ∈ s.image g, f x = ∏ x ∈ s.image g, ∏ x ∈ s.filter fun c' => g c' = x, h x :=
(prod_congr rfl) fun _x hx =>
let ⟨c, hcs, hc⟩ := mem_image.1 hx
hc ▸ eq c hcs
_ = ∏ x ∈ s, h x := prod_fiberwise_of_maps_to (fun _x => mem_image_of_mem g) _
#align finset.prod_image' Finset.prod_image'
#align finset.sum_image' Finset.sum_image'
@[to_additive]
theorem prod_mul_distrib : ∏ x ∈ s, f x * g x = (∏ x ∈ s, f x) * ∏ x ∈ s, g x :=
Eq.trans (by rw [one_mul]; rfl) fold_op_distrib
#align finset.prod_mul_distrib Finset.prod_mul_distrib
#align finset.sum_add_distrib Finset.sum_add_distrib
@[to_additive]
lemma prod_mul_prod_comm (f g h i : α → β) :
(∏ a ∈ s, f a * g a) * ∏ a ∈ s, h a * i a = (∏ a ∈ s, f a * h a) * ∏ a ∈ s, g a * i a := by
simp_rw [prod_mul_distrib, mul_mul_mul_comm]
@[to_additive]
theorem prod_product {s : Finset γ} {t : Finset α} {f : γ × α → β} :
∏ x ∈ s ×ˢ t, f x = ∏ x ∈ s, ∏ y ∈ t, f (x, y) :=
prod_finset_product (s ×ˢ t) s (fun _a => t) fun _p => mem_product
#align finset.prod_product Finset.prod_product
#align finset.sum_product Finset.sum_product
@[to_additive "An uncurried version of `Finset.sum_product`"]
theorem prod_product' {s : Finset γ} {t : Finset α} {f : γ → α → β} :
∏ x ∈ s ×ˢ t, f x.1 x.2 = ∏ x ∈ s, ∏ y ∈ t, f x y :=
prod_product
#align finset.prod_product' Finset.prod_product'
#align finset.sum_product' Finset.sum_product'
@[to_additive]
theorem prod_product_right {s : Finset γ} {t : Finset α} {f : γ × α → β} :
∏ x ∈ s ×ˢ t, f x = ∏ y ∈ t, ∏ x ∈ s, f (x, y) :=
prod_finset_product_right (s ×ˢ t) t (fun _a => s) fun _p => mem_product.trans and_comm
#align finset.prod_product_right Finset.prod_product_right
#align finset.sum_product_right Finset.sum_product_right
@[to_additive "An uncurried version of `Finset.sum_product_right`"]
theorem prod_product_right' {s : Finset γ} {t : Finset α} {f : γ → α → β} :
∏ x ∈ s ×ˢ t, f x.1 x.2 = ∏ y ∈ t, ∏ x ∈ s, f x y :=
prod_product_right
#align finset.prod_product_right' Finset.prod_product_right'
#align finset.sum_product_right' Finset.sum_product_right'
@[to_additive "Generalization of `Finset.sum_comm` to the case when the inner `Finset`s depend on
the outer variable."]
theorem prod_comm' {s : Finset γ} {t : γ → Finset α} {t' : Finset α} {s' : α → Finset γ}
(h : ∀ x y, x ∈ s ∧ y ∈ t x ↔ x ∈ s' y ∧ y ∈ t') {f : γ → α → β} :
(∏ x ∈ s, ∏ y ∈ t x, f x y) = ∏ y ∈ t', ∏ x ∈ s' y, f x y := by
classical
have : ∀ z : γ × α, (z ∈ s.biUnion fun x => (t x).map <| Function.Embedding.sectr x _) ↔
z.1 ∈ s ∧ z.2 ∈ t z.1 := by
rintro ⟨x, y⟩
simp only [mem_biUnion, mem_map, Function.Embedding.sectr_apply, Prod.mk.injEq,
exists_eq_right, ← and_assoc]
exact
(prod_finset_product' _ _ _ this).symm.trans
((prod_finset_product_right' _ _ _) fun ⟨x, y⟩ => (this _).trans ((h x y).trans and_comm))
#align finset.prod_comm' Finset.prod_comm'
#align finset.sum_comm' Finset.sum_comm'
@[to_additive]
theorem prod_comm {s : Finset γ} {t : Finset α} {f : γ → α → β} :
(∏ x ∈ s, ∏ y ∈ t, f x y) = ∏ y ∈ t, ∏ x ∈ s, f x y :=
prod_comm' fun _ _ => Iff.rfl
#align finset.prod_comm Finset.prod_comm
#align finset.sum_comm Finset.sum_comm
@[to_additive]
theorem prod_hom_rel [CommMonoid γ] {r : β → γ → Prop} {f : α → β} {g : α → γ} {s : Finset α}
(h₁ : r 1 1) (h₂ : ∀ a b c, r b c → r (f a * b) (g a * c)) :
r (∏ x ∈ s, f x) (∏ x ∈ s, g x) := by
delta Finset.prod
apply Multiset.prod_hom_rel <;> assumption
#align finset.prod_hom_rel Finset.prod_hom_rel
#align finset.sum_hom_rel Finset.sum_hom_rel
@[to_additive]
theorem prod_filter_of_ne {p : α → Prop} [DecidablePred p] (hp : ∀ x ∈ s, f x ≠ 1 → p x) :
∏ x ∈ s.filter p, f x = ∏ x ∈ s, f x :=
(prod_subset (filter_subset _ _)) fun x => by
classical
rw [not_imp_comm, mem_filter]
exact fun h₁ h₂ => ⟨h₁, by simpa using hp _ h₁ h₂⟩
#align finset.prod_filter_of_ne Finset.prod_filter_of_ne
#align finset.sum_filter_of_ne Finset.sum_filter_of_ne
-- If we use `[DecidableEq β]` here, some rewrites fail because they find a wrong `Decidable`
-- instance first; `{∀ x, Decidable (f x ≠ 1)}` doesn't work with `rw ← prod_filter_ne_one`
@[to_additive]
theorem prod_filter_ne_one (s : Finset α) [∀ x, Decidable (f x ≠ 1)] :
∏ x ∈ s.filter fun x => f x ≠ 1, f x = ∏ x ∈ s, f x :=
prod_filter_of_ne fun _ _ => id
#align finset.prod_filter_ne_one Finset.prod_filter_ne_one
#align finset.sum_filter_ne_zero Finset.sum_filter_ne_zero
@[to_additive]
theorem prod_filter (p : α → Prop) [DecidablePred p] (f : α → β) :
∏ a ∈ s.filter p, f a = ∏ a ∈ s, if p a then f a else 1 :=
calc
∏ a ∈ s.filter p, f a = ∏ a ∈ s.filter p, if p a then f a else 1 :=
prod_congr rfl fun a h => by rw [if_pos]; simpa using (mem_filter.1 h).2
_ = ∏ a ∈ s, if p a then f a else 1 := by
{ refine prod_subset (filter_subset _ s) fun x hs h => ?_
rw [mem_filter, not_and] at h
exact if_neg (by simpa using h hs) }
#align finset.prod_filter Finset.prod_filter
#align finset.sum_filter Finset.sum_filter
@[to_additive]
theorem prod_eq_single_of_mem {s : Finset α} {f : α → β} (a : α) (h : a ∈ s)
(h₀ : ∀ b ∈ s, b ≠ a → f b = 1) : ∏ x ∈ s, f x = f a := by
haveI := Classical.decEq α
calc
∏ x ∈ s, f x = ∏ x ∈ {a}, f x := by
{ refine (prod_subset ?_ ?_).symm
· intro _ H
rwa [mem_singleton.1 H]
· simpa only [mem_singleton] }
_ = f a := prod_singleton _ _
#align finset.prod_eq_single_of_mem Finset.prod_eq_single_of_mem
#align finset.sum_eq_single_of_mem Finset.sum_eq_single_of_mem
@[to_additive]
theorem prod_eq_single {s : Finset α} {f : α → β} (a : α) (h₀ : ∀ b ∈ s, b ≠ a → f b = 1)
(h₁ : a ∉ s → f a = 1) : ∏ x ∈ s, f x = f a :=
haveI := Classical.decEq α
by_cases (prod_eq_single_of_mem a · h₀) fun this =>
(prod_congr rfl fun b hb => h₀ b hb <| by rintro rfl; exact this hb).trans <|
prod_const_one.trans (h₁ this).symm
#align finset.prod_eq_single Finset.prod_eq_single
#align finset.sum_eq_single Finset.sum_eq_single
@[to_additive]
lemma prod_union_eq_left [DecidableEq α] (hs : ∀ a ∈ s₂, a ∉ s₁ → f a = 1) :
∏ a ∈ s₁ ∪ s₂, f a = ∏ a ∈ s₁, f a :=
Eq.symm <|
prod_subset subset_union_left fun _a ha ha' ↦ hs _ ((mem_union.1 ha).resolve_left ha') ha'
@[to_additive]
lemma prod_union_eq_right [DecidableEq α] (hs : ∀ a ∈ s₁, a ∉ s₂ → f a = 1) :
∏ a ∈ s₁ ∪ s₂, f a = ∏ a ∈ s₂, f a := by rw [union_comm, prod_union_eq_left hs]
@[to_additive]
theorem prod_eq_mul_of_mem {s : Finset α} {f : α → β} (a b : α) (ha : a ∈ s) (hb : b ∈ s)
(hn : a ≠ b) (h₀ : ∀ c ∈ s, c ≠ a ∧ c ≠ b → f c = 1) : ∏ x ∈ s, f x = f a * f b := by
haveI := Classical.decEq α; let s' := ({a, b} : Finset α)
have hu : s' ⊆ s := by
refine insert_subset_iff.mpr ?_
apply And.intro ha
apply singleton_subset_iff.mpr hb
have hf : ∀ c ∈ s, c ∉ s' → f c = 1 := by
intro c hc hcs
apply h₀ c hc
apply not_or.mp
intro hab
apply hcs
rw [mem_insert, mem_singleton]
exact hab
rw [← prod_subset hu hf]
exact Finset.prod_pair hn
#align finset.prod_eq_mul_of_mem Finset.prod_eq_mul_of_mem
#align finset.sum_eq_add_of_mem Finset.sum_eq_add_of_mem
@[to_additive]
theorem prod_eq_mul {s : Finset α} {f : α → β} (a b : α) (hn : a ≠ b)
(h₀ : ∀ c ∈ s, c ≠ a ∧ c ≠ b → f c = 1) (ha : a ∉ s → f a = 1) (hb : b ∉ s → f b = 1) :
∏ x ∈ s, f x = f a * f b := by
haveI := Classical.decEq α; by_cases h₁ : a ∈ s <;> by_cases h₂ : b ∈ s
· exact prod_eq_mul_of_mem a b h₁ h₂ hn h₀
· rw [hb h₂, mul_one]
apply prod_eq_single_of_mem a h₁
exact fun c hc hca => h₀ c hc ⟨hca, ne_of_mem_of_not_mem hc h₂⟩
· rw [ha h₁, one_mul]
apply prod_eq_single_of_mem b h₂
exact fun c hc hcb => h₀ c hc ⟨ne_of_mem_of_not_mem hc h₁, hcb⟩
· rw [ha h₁, hb h₂, mul_one]
exact
_root_.trans
(prod_congr rfl fun c hc =>
h₀ c hc ⟨ne_of_mem_of_not_mem hc h₁, ne_of_mem_of_not_mem hc h₂⟩)
prod_const_one
#align finset.prod_eq_mul Finset.prod_eq_mul
#align finset.sum_eq_add Finset.sum_eq_add
-- Porting note: simpNF linter complains that LHS doesn't simplify, but it does
@[to_additive (attr := simp, nolint simpNF)
"A sum over `s.subtype p` equals one over `s.filter p`."]
theorem prod_subtype_eq_prod_filter (f : α → β) {p : α → Prop} [DecidablePred p] :
∏ x ∈ s.subtype p, f x = ∏ x ∈ s.filter p, f x := by
conv_lhs => erw [← prod_map (s.subtype p) (Function.Embedding.subtype _) f]
exact prod_congr (subtype_map _) fun x _hx => rfl
#align finset.prod_subtype_eq_prod_filter Finset.prod_subtype_eq_prod_filter
#align finset.sum_subtype_eq_sum_filter Finset.sum_subtype_eq_sum_filter
@[to_additive "If all elements of a `Finset` satisfy the predicate `p`, a sum
over `s.subtype p` equals that sum over `s`."]
theorem prod_subtype_of_mem (f : α → β) {p : α → Prop} [DecidablePred p] (h : ∀ x ∈ s, p x) :
∏ x ∈ s.subtype p, f x = ∏ x ∈ s, f x := by
rw [prod_subtype_eq_prod_filter, filter_true_of_mem]
simpa using h
#align finset.prod_subtype_of_mem Finset.prod_subtype_of_mem
#align finset.sum_subtype_of_mem Finset.sum_subtype_of_mem
@[to_additive "A sum of a function over a `Finset` in a subtype equals a
sum in the main type of a function that agrees with the first
function on that `Finset`."]
theorem prod_subtype_map_embedding {p : α → Prop} {s : Finset { x // p x }} {f : { x // p x } → β}
{g : α → β} (h : ∀ x : { x // p x }, x ∈ s → g x = f x) :
(∏ x ∈ s.map (Function.Embedding.subtype _), g x) = ∏ x ∈ s, f x := by
rw [Finset.prod_map]
exact Finset.prod_congr rfl h
#align finset.prod_subtype_map_embedding Finset.prod_subtype_map_embedding
#align finset.sum_subtype_map_embedding Finset.sum_subtype_map_embedding
variable (f s)
@[to_additive]
theorem prod_coe_sort_eq_attach (f : s → β) : ∏ i : s, f i = ∏ i ∈ s.attach, f i :=
rfl
#align finset.prod_coe_sort_eq_attach Finset.prod_coe_sort_eq_attach
#align finset.sum_coe_sort_eq_attach Finset.sum_coe_sort_eq_attach
@[to_additive]
theorem prod_coe_sort : ∏ i : s, f i = ∏ i ∈ s, f i := prod_attach _ _
#align finset.prod_coe_sort Finset.prod_coe_sort
#align finset.sum_coe_sort Finset.sum_coe_sort
@[to_additive]
theorem prod_finset_coe (f : α → β) (s : Finset α) : (∏ i : (s : Set α), f i) = ∏ i ∈ s, f i :=
prod_coe_sort s f
#align finset.prod_finset_coe Finset.prod_finset_coe
#align finset.sum_finset_coe Finset.sum_finset_coe
variable {f s}
@[to_additive]
theorem prod_subtype {p : α → Prop} {F : Fintype (Subtype p)} (s : Finset α) (h : ∀ x, x ∈ s ↔ p x)
(f : α → β) : ∏ a ∈ s, f a = ∏ a : Subtype p, f a := by
have : (· ∈ s) = p := Set.ext h
subst p
rw [← prod_coe_sort]
congr!
#align finset.prod_subtype Finset.prod_subtype
#align finset.sum_subtype Finset.sum_subtype
@[to_additive]
lemma prod_preimage' (f : ι → κ) [DecidablePred (· ∈ Set.range f)] (s : Finset κ) (hf) (g : κ → β) :
∏ x ∈ s.preimage f hf, g (f x) = ∏ x ∈ s.filter (· ∈ Set.range f), g x := by
classical
calc
∏ x ∈ preimage s f hf, g (f x) = ∏ x ∈ image f (preimage s f hf), g x :=
Eq.symm <| prod_image <| by simpa only [mem_preimage, Set.InjOn] using hf
_ = ∏ x ∈ s.filter fun x => x ∈ Set.range f, g x := by rw [image_preimage]
#align finset.prod_preimage' Finset.prod_preimage'
#align finset.sum_preimage' Finset.sum_preimage'
@[to_additive]
lemma prod_preimage (f : ι → κ) (s : Finset κ) (hf) (g : κ → β)
(hg : ∀ x ∈ s, x ∉ Set.range f → g x = 1) :
∏ x ∈ s.preimage f hf, g (f x) = ∏ x ∈ s, g x := by
classical rw [prod_preimage', prod_filter_of_ne]; exact fun x hx ↦ Not.imp_symm (hg x hx)
#align finset.prod_preimage Finset.prod_preimage
#align finset.sum_preimage Finset.sum_preimage
@[to_additive]
lemma prod_preimage_of_bij (f : ι → κ) (s : Finset κ) (hf : Set.BijOn f (f ⁻¹' ↑s) ↑s) (g : κ → β) :
∏ x ∈ s.preimage f hf.injOn, g (f x) = ∏ x ∈ s, g x :=
prod_preimage _ _ hf.injOn g fun _ hs h_f ↦ (h_f <| hf.subset_range hs).elim
#align finset.prod_preimage_of_bij Finset.prod_preimage_of_bij
#align finset.sum_preimage_of_bij Finset.sum_preimage_of_bij
@[to_additive]
theorem prod_set_coe (s : Set α) [Fintype s] : (∏ i : s, f i) = ∏ i ∈ s.toFinset, f i :=
(Finset.prod_subtype s.toFinset (fun _ ↦ Set.mem_toFinset) f).symm
@[to_additive "The sum of a function `g` defined only on a set `s` is equal to
the sum of a function `f` defined everywhere,
as long as `f` and `g` agree on `s`, and `f = 0` off `s`."]
theorem prod_congr_set {α : Type*} [CommMonoid α] {β : Type*} [Fintype β] (s : Set β)
[DecidablePred (· ∈ s)] (f : β → α) (g : s → α) (w : ∀ (x : β) (h : x ∈ s), f x = g ⟨x, h⟩)
(w' : ∀ x : β, x ∉ s → f x = 1) : Finset.univ.prod f = Finset.univ.prod g := by
rw [← @Finset.prod_subset _ _ s.toFinset Finset.univ f _ (by simp)]
· rw [Finset.prod_subtype]
· apply Finset.prod_congr rfl
exact fun ⟨x, h⟩ _ => w x h
· simp
· rintro x _ h
exact w' x (by simpa using h)
#align finset.prod_congr_set Finset.prod_congr_set
#align finset.sum_congr_set Finset.sum_congr_set
@[to_additive]
theorem prod_apply_dite {s : Finset α} {p : α → Prop} {hp : DecidablePred p}
[DecidablePred fun x => ¬p x] (f : ∀ x : α, p x → γ) (g : ∀ x : α, ¬p x → γ) (h : γ → β) :
(∏ x ∈ s, h (if hx : p x then f x hx else g x hx)) =
(∏ x ∈ (s.filter p).attach, h (f x.1 <| by simpa using (mem_filter.mp x.2).2)) *
∏ x ∈ (s.filter fun x => ¬p x).attach, h (g x.1 <| by simpa using (mem_filter.mp x.2).2) :=
calc
(∏ x ∈ s, h (if hx : p x then f x hx else g x hx)) =
(∏ x ∈ s.filter p, h (if hx : p x then f x hx else g x hx)) *
∏ x ∈ s.filter (¬p ·), h (if hx : p x then f x hx else g x hx) :=
(prod_filter_mul_prod_filter_not s p _).symm
_ = (∏ x ∈ (s.filter p).attach, h (if hx : p x.1 then f x.1 hx else g x.1 hx)) *
∏ x ∈ (s.filter (¬p ·)).attach, h (if hx : p x.1 then f x.1 hx else g x.1 hx) :=
congr_arg₂ _ (prod_attach _ _).symm (prod_attach _ _).symm
_ = (∏ x ∈ (s.filter p).attach, h (f x.1 <| by simpa using (mem_filter.mp x.2).2)) *
∏ x ∈ (s.filter (¬p ·)).attach, h (g x.1 <| by simpa using (mem_filter.mp x.2).2) :=
congr_arg₂ _ (prod_congr rfl fun x _hx ↦
congr_arg h (dif_pos <| by simpa using (mem_filter.mp x.2).2))
(prod_congr rfl fun x _hx => congr_arg h (dif_neg <| by simpa using (mem_filter.mp x.2).2))
#align finset.prod_apply_dite Finset.prod_apply_dite
#align finset.sum_apply_dite Finset.sum_apply_dite
@[to_additive]
theorem prod_apply_ite {s : Finset α} {p : α → Prop} {_hp : DecidablePred p} (f g : α → γ)
(h : γ → β) :
(∏ x ∈ s, h (if p x then f x else g x)) =
(∏ x ∈ s.filter p, h (f x)) * ∏ x ∈ s.filter fun x => ¬p x, h (g x) :=
(prod_apply_dite _ _ _).trans <| congr_arg₂ _ (prod_attach _ (h ∘ f)) (prod_attach _ (h ∘ g))
#align finset.prod_apply_ite Finset.prod_apply_ite
#align finset.sum_apply_ite Finset.sum_apply_ite
@[to_additive]
theorem prod_dite {s : Finset α} {p : α → Prop} {hp : DecidablePred p} (f : ∀ x : α, p x → β)
(g : ∀ x : α, ¬p x → β) :
∏ x ∈ s, (if hx : p x then f x hx else g x hx) =
(∏ x ∈ (s.filter p).attach, f x.1 (by simpa using (mem_filter.mp x.2).2)) *
∏ x ∈ (s.filter fun x => ¬p x).attach, g x.1 (by simpa using (mem_filter.mp x.2).2) := by
simp [prod_apply_dite _ _ fun x => x]
#align finset.prod_dite Finset.prod_dite
#align finset.sum_dite Finset.sum_dite
@[to_additive]
theorem prod_ite {s : Finset α} {p : α → Prop} {hp : DecidablePred p} (f g : α → β) :
∏ x ∈ s, (if p x then f x else g x) =
(∏ x ∈ s.filter p, f x) * ∏ x ∈ s.filter fun x => ¬p x, g x := by
simp [prod_apply_ite _ _ fun x => x]
#align finset.prod_ite Finset.prod_ite
#align finset.sum_ite Finset.sum_ite
@[to_additive]
theorem prod_ite_of_false {p : α → Prop} {hp : DecidablePred p} (f g : α → β) (h : ∀ x ∈ s, ¬p x) :
∏ x ∈ s, (if p x then f x else g x) = ∏ x ∈ s, g x := by
rw [prod_ite, filter_false_of_mem, filter_true_of_mem]
· simp only [prod_empty, one_mul]
all_goals intros; apply h; assumption
#align finset.prod_ite_of_false Finset.prod_ite_of_false
#align finset.sum_ite_of_false Finset.sum_ite_of_false
@[to_additive]
theorem prod_ite_of_true {p : α → Prop} {hp : DecidablePred p} (f g : α → β) (h : ∀ x ∈ s, p x) :
∏ x ∈ s, (if p x then f x else g x) = ∏ x ∈ s, f x := by
simp_rw [← ite_not (p _)]
apply prod_ite_of_false
simpa
#align finset.prod_ite_of_true Finset.prod_ite_of_true
#align finset.sum_ite_of_true Finset.sum_ite_of_true
@[to_additive]
theorem prod_apply_ite_of_false {p : α → Prop} {hp : DecidablePred p} (f g : α → γ) (k : γ → β)
(h : ∀ x ∈ s, ¬p x) : (∏ x ∈ s, k (if p x then f x else g x)) = ∏ x ∈ s, k (g x) := by
simp_rw [apply_ite k]
exact prod_ite_of_false _ _ h
#align finset.prod_apply_ite_of_false Finset.prod_apply_ite_of_false
#align finset.sum_apply_ite_of_false Finset.sum_apply_ite_of_false
@[to_additive]
theorem prod_apply_ite_of_true {p : α → Prop} {hp : DecidablePred p} (f g : α → γ) (k : γ → β)
(h : ∀ x ∈ s, p x) : (∏ x ∈ s, k (if p x then f x else g x)) = ∏ x ∈ s, k (f x) := by
simp_rw [apply_ite k]
exact prod_ite_of_true _ _ h
#align finset.prod_apply_ite_of_true Finset.prod_apply_ite_of_true
#align finset.sum_apply_ite_of_true Finset.sum_apply_ite_of_true
@[to_additive]
theorem prod_extend_by_one [DecidableEq α] (s : Finset α) (f : α → β) :
∏ i ∈ s, (if i ∈ s then f i else 1) = ∏ i ∈ s, f i :=
(prod_congr rfl) fun _i hi => if_pos hi
#align finset.prod_extend_by_one Finset.prod_extend_by_one
#align finset.sum_extend_by_zero Finset.sum_extend_by_zero
@[to_additive (attr := simp)]
theorem prod_ite_mem [DecidableEq α] (s t : Finset α) (f : α → β) :
∏ i ∈ s, (if i ∈ t then f i else 1) = ∏ i ∈ s ∩ t, f i := by
rw [← Finset.prod_filter, Finset.filter_mem_eq_inter]
#align finset.prod_ite_mem Finset.prod_ite_mem
#align finset.sum_ite_mem Finset.sum_ite_mem
@[to_additive (attr := simp)]
theorem prod_dite_eq [DecidableEq α] (s : Finset α) (a : α) (b : ∀ x : α, a = x → β) :
∏ x ∈ s, (if h : a = x then b x h else 1) = ite (a ∈ s) (b a rfl) 1 := by
split_ifs with h
· rw [Finset.prod_eq_single a, dif_pos rfl]
· intros _ _ h
rw [dif_neg]
exact h.symm
· simp [h]
· rw [Finset.prod_eq_one]
intros
rw [dif_neg]
rintro rfl
contradiction
#align finset.prod_dite_eq Finset.prod_dite_eq
#align finset.sum_dite_eq Finset.sum_dite_eq
@[to_additive (attr := simp)]
theorem prod_dite_eq' [DecidableEq α] (s : Finset α) (a : α) (b : ∀ x : α, x = a → β) :
∏ x ∈ s, (if h : x = a then b x h else 1) = ite (a ∈ s) (b a rfl) 1 := by
split_ifs with h
· rw [Finset.prod_eq_single a, dif_pos rfl]
· intros _ _ h
rw [dif_neg]
exact h
· simp [h]
· rw [Finset.prod_eq_one]
intros
rw [dif_neg]
rintro rfl
contradiction
#align finset.prod_dite_eq' Finset.prod_dite_eq'
#align finset.sum_dite_eq' Finset.sum_dite_eq'
@[to_additive (attr := simp)]
theorem prod_ite_eq [DecidableEq α] (s : Finset α) (a : α) (b : α → β) :
(∏ x ∈ s, ite (a = x) (b x) 1) = ite (a ∈ s) (b a) 1 :=
prod_dite_eq s a fun x _ => b x
#align finset.prod_ite_eq Finset.prod_ite_eq
#align finset.sum_ite_eq Finset.sum_ite_eq
@[to_additive (attr := simp) "A sum taken over a conditional whose condition is an equality
test on the index and whose alternative is `0` has value either the term at that index or `0`.
The difference with `Finset.sum_ite_eq` is that the arguments to `Eq` are swapped."]
theorem prod_ite_eq' [DecidableEq α] (s : Finset α) (a : α) (b : α → β) :
(∏ x ∈ s, ite (x = a) (b x) 1) = ite (a ∈ s) (b a) 1 :=
prod_dite_eq' s a fun x _ => b x
#align finset.prod_ite_eq' Finset.prod_ite_eq'
#align finset.sum_ite_eq' Finset.sum_ite_eq'
@[to_additive]
theorem prod_ite_index (p : Prop) [Decidable p] (s t : Finset α) (f : α → β) :
∏ x ∈ if p then s else t, f x = if p then ∏ x ∈ s, f x else ∏ x ∈ t, f x :=
apply_ite (fun s => ∏ x ∈ s, f x) _ _ _
#align finset.prod_ite_index Finset.prod_ite_index
#align finset.sum_ite_index Finset.sum_ite_index
@[to_additive (attr := simp)]
theorem prod_ite_irrel (p : Prop) [Decidable p] (s : Finset α) (f g : α → β) :
∏ x ∈ s, (if p then f x else g x) = if p then ∏ x ∈ s, f x else ∏ x ∈ s, g x := by
split_ifs with h <;> rfl
#align finset.prod_ite_irrel Finset.prod_ite_irrel
#align finset.sum_ite_irrel Finset.sum_ite_irrel
@[to_additive (attr := simp)]
theorem prod_dite_irrel (p : Prop) [Decidable p] (s : Finset α) (f : p → α → β) (g : ¬p → α → β) :
∏ x ∈ s, (if h : p then f h x else g h x) =
if h : p then ∏ x ∈ s, f h x else ∏ x ∈ s, g h x := by
split_ifs with h <;> rfl
#align finset.prod_dite_irrel Finset.prod_dite_irrel
#align finset.sum_dite_irrel Finset.sum_dite_irrel
@[to_additive (attr := simp)]
theorem prod_pi_mulSingle' [DecidableEq α] (a : α) (x : β) (s : Finset α) :
∏ a' ∈ s, Pi.mulSingle a x a' = if a ∈ s then x else 1 :=
prod_dite_eq' _ _ _
#align finset.prod_pi_mul_single' Finset.prod_pi_mulSingle'
#align finset.sum_pi_single' Finset.sum_pi_single'
@[to_additive (attr := simp)]
theorem prod_pi_mulSingle {β : α → Type*} [DecidableEq α] [∀ a, CommMonoid (β a)] (a : α)
(f : ∀ a, β a) (s : Finset α) :
(∏ a' ∈ s, Pi.mulSingle a' (f a') a) = if a ∈ s then f a else 1 :=
prod_dite_eq _ _ _
#align finset.prod_pi_mul_single Finset.prod_pi_mulSingle
@[to_additive]
lemma mulSupport_prod (s : Finset ι) (f : ι → α → β) :
mulSupport (fun x ↦ ∏ i ∈ s, f i x) ⊆ ⋃ i ∈ s, mulSupport (f i) := by
simp only [mulSupport_subset_iff', Set.mem_iUnion, not_exists, nmem_mulSupport]
exact fun x ↦ prod_eq_one
#align function.mul_support_prod Finset.mulSupport_prod
#align function.support_sum Finset.support_sum
theorem card_eq_sum_ones (s : Finset α) : s.card = ∑ x ∈ s, 1 := by simp
#align finset.card_eq_sum_ones Finset.card_eq_sum_ones
theorem sum_const_nat {m : ℕ} {f : α → ℕ} (h₁ : ∀ x ∈ s, f x = m) :
∑ x ∈ s, f x = card s * m := by
rw [← Nat.nsmul_eq_mul, ← sum_const]
apply sum_congr rfl h₁
#align finset.sum_const_nat Finset.sum_const_nat
lemma sum_card_fiberwise_eq_card_filter {κ : Type*} [DecidableEq κ] (s : Finset ι) (t : Finset κ)
(g : ι → κ) : ∑ j ∈ t, (s.filter fun i ↦ g i = j).card = (s.filter fun i ↦ g i ∈ t).card := by
simpa only [card_eq_sum_ones] using sum_fiberwise_eq_sum_filter _ _ _ _
lemma card_filter (p) [DecidablePred p] (s : Finset α) :
(filter p s).card = ∑ a ∈ s, ite (p a) 1 0 := by simp [sum_ite]
#align finset.card_filter Finset.card_filter
namespace Fintype
variable {ι κ α : Type*} [Fintype ι] [Fintype κ]
open Finset
section CommMonoid
variable [CommMonoid α]
@[to_additive "`Fintype.sum_bijective` is a variant of `Finset.sum_bij` that accepts
`Function.Bijective`.
See `Function.Bijective.sum_comp` for a version without `h`. "]
lemma prod_bijective (e : ι → κ) (he : e.Bijective) (f : ι → α) (g : κ → α)
(h : ∀ x, f x = g (e x)) : ∏ x, f x = ∏ x, g x :=
prod_equiv (.ofBijective e he) (by simp) (by simp [h])
#align fintype.prod_bijective Fintype.prod_bijective
#align fintype.sum_bijective Fintype.sum_bijective
@[to_additive] alias _root_.Function.Bijective.finset_prod := prod_bijective
@[to_additive "`Fintype.sum_equiv` is a specialization of `Finset.sum_bij` that
automatically fills in most arguments.
See `Equiv.sum_comp` for a version without `h`."]
lemma prod_equiv (e : ι ≃ κ) (f : ι → α) (g : κ → α) (h : ∀ x, f x = g (e x)) :
∏ x, f x = ∏ x, g x := prod_bijective _ e.bijective _ _ h
#align fintype.prod_equiv Fintype.prod_equiv
#align fintype.sum_equiv Fintype.sum_equiv
@[to_additive]
lemma _root_.Function.Bijective.prod_comp {e : ι → κ} (he : e.Bijective) (g : κ → α) :
∏ i, g (e i) = ∏ i, g i := prod_bijective _ he _ _ fun _ ↦ rfl
#align function.bijective.prod_comp Function.Bijective.prod_comp
#align function.bijective.sum_comp Function.Bijective.sum_comp
@[to_additive]
lemma _root_.Equiv.prod_comp (e : ι ≃ κ) (g : κ → α) : ∏ i, g (e i) = ∏ i, g i :=
prod_equiv e _ _ fun _ ↦ rfl
#align equiv.prod_comp Equiv.prod_comp
#align equiv.sum_comp Equiv.sum_comp
@[to_additive]
lemma prod_of_injective (e : ι → κ) (he : Injective e) (f : ι → α) (g : κ → α)
(h' : ∀ i ∉ Set.range e, g i = 1) (h : ∀ i, f i = g (e i)) : ∏ i, f i = ∏ j, g j :=
prod_of_injOn e he.injOn (by simp) (by simpa using h') (fun i _ ↦ h i)
@[to_additive]
lemma prod_fiberwise [DecidableEq κ] (g : ι → κ) (f : ι → α) :
∏ j, ∏ i : {i // g i = j}, f i = ∏ i, f i := by
rw [← Finset.prod_fiberwise _ g f]
congr with j
exact (prod_subtype _ (by simp) _).symm
#align fintype.prod_fiberwise Fintype.prod_fiberwise
#align fintype.sum_fiberwise Fintype.sum_fiberwise
@[to_additive]
lemma prod_fiberwise' [DecidableEq κ] (g : ι → κ) (f : κ → α) :
∏ j, ∏ _i : {i // g i = j}, f j = ∏ i, f (g i) := by
rw [← Finset.prod_fiberwise' _ g f]
congr with j
exact (prod_subtype _ (by simp) fun _ ↦ _).symm
@[to_additive]
| Mathlib/Algebra/BigOperators/Group/Finset.lean | 2,304 | 2,305 | theorem prod_unique {α β : Type*} [CommMonoid β] [Unique α] [Fintype α] (f : α → β) :
∏ x : α, f x = f default := by | rw [univ_unique, prod_singleton]
|
import Mathlib.Analysis.MeanInequalities
import Mathlib.Data.Fintype.Order
import Mathlib.LinearAlgebra.Matrix.Basis
import Mathlib.Analysis.NormedSpace.WithLp
#align_import analysis.normed_space.pi_Lp from "leanprover-community/mathlib"@"9d013ad8430ddddd350cff5c3db830278ded3c79"
set_option linter.uppercaseLean3 false
open Real Set Filter RCLike Bornology Uniformity Topology NNReal ENNReal
noncomputable section
abbrev PiLp (p : ℝ≥0∞) {ι : Type*} (α : ι → Type*) : Type _ :=
WithLp p (∀ i : ι, α i)
#align pi_Lp PiLp
instance (p : ℝ≥0∞) {ι : Type*} (α : ι → Type*) : CoeFun (PiLp p α) (fun _ ↦ (i : ι) → α i) where
coe := WithLp.equiv p _
instance (p : ℝ≥0∞) {ι : Type*} (α : ι → Type*) [∀ i, Inhabited (α i)] : Inhabited (PiLp p α) :=
⟨fun _ => default⟩
@[ext] -- Porting note (#10756): new lemma
protected theorem PiLp.ext {p : ℝ≥0∞} {ι : Type*} {α : ι → Type*} {x y : PiLp p α}
(h : ∀ i, x i = y i) : x = y := funext h
namespace PiLp
variable (p : ℝ≥0∞) (𝕜 : Type*) {ι : Type*} (α : ι → Type*) (β : ι → Type*)
section
variable {𝕜 p α}
variable [SeminormedRing 𝕜] [∀ i, SeminormedAddCommGroup (β i)]
variable [∀ i, Module 𝕜 (β i)] [∀ i, BoundedSMul 𝕜 (β i)] (c : 𝕜)
variable (x y : PiLp p β) (i : ι)
@[simp]
theorem zero_apply : (0 : PiLp p β) i = 0 :=
rfl
#align pi_Lp.zero_apply PiLp.zero_apply
@[simp]
theorem add_apply : (x + y) i = x i + y i :=
rfl
#align pi_Lp.add_apply PiLp.add_apply
@[simp]
theorem sub_apply : (x - y) i = x i - y i :=
rfl
#align pi_Lp.sub_apply PiLp.sub_apply
@[simp]
theorem smul_apply : (c • x) i = c • x i :=
rfl
#align pi_Lp.smul_apply PiLp.smul_apply
@[simp]
theorem neg_apply : (-x) i = -x i :=
rfl
#align pi_Lp.neg_apply PiLp.neg_apply
end
@[simp]
theorem _root_.WithLp.equiv_pi_apply (x : PiLp p α) (i : ι) : WithLp.equiv p _ x i = x i :=
rfl
#align pi_Lp.equiv_apply WithLp.equiv_pi_apply
@[simp]
theorem _root_.WithLp.equiv_symm_pi_apply (x : ∀ i, α i) (i : ι) :
(WithLp.equiv p _).symm x i = x i :=
rfl
#align pi_Lp.equiv_symm_apply WithLp.equiv_symm_pi_apply
section DistNorm
variable [Fintype ι]
instance uniformSpace [∀ i, UniformSpace (β i)] : UniformSpace (PiLp p β) :=
Pi.uniformSpace _
#align pi_Lp.uniform_space PiLp.uniformSpace
theorem uniformContinuous_equiv [∀ i, UniformSpace (β i)] :
UniformContinuous (WithLp.equiv p (∀ i, β i)) :=
uniformContinuous_id
#align pi_Lp.uniform_continuous_equiv PiLp.uniformContinuous_equiv
theorem uniformContinuous_equiv_symm [∀ i, UniformSpace (β i)] :
UniformContinuous (WithLp.equiv p (∀ i, β i)).symm :=
uniformContinuous_id
#align pi_Lp.uniform_continuous_equiv_symm PiLp.uniformContinuous_equiv_symm
@[continuity]
theorem continuous_equiv [∀ i, UniformSpace (β i)] : Continuous (WithLp.equiv p (∀ i, β i)) :=
continuous_id
#align pi_Lp.continuous_equiv PiLp.continuous_equiv
@[continuity]
theorem continuous_equiv_symm [∀ i, UniformSpace (β i)] :
Continuous (WithLp.equiv p (∀ i, β i)).symm :=
continuous_id
#align pi_Lp.continuous_equiv_symm PiLp.continuous_equiv_symm
instance bornology [∀ i, Bornology (β i)] : Bornology (PiLp p β) :=
Pi.instBornology
#align pi_Lp.bornology PiLp.bornology
-- throughout the rest of the file, we assume `1 ≤ p`
variable [Fact (1 ≤ p)]
section Fintype
variable [Fintype ι]
instance [∀ i, PseudoEMetricSpace (β i)] : PseudoEMetricSpace (PiLp p β) :=
(pseudoEmetricAux p β).replaceUniformity (aux_uniformity_eq p β).symm
instance [∀ i, EMetricSpace (α i)] : EMetricSpace (PiLp p α) :=
@EMetricSpace.ofT0PseudoEMetricSpace (PiLp p α) _ Pi.instT0Space
instance [∀ i, PseudoMetricSpace (β i)] : PseudoMetricSpace (PiLp p β) :=
((pseudoMetricAux p β).replaceUniformity (aux_uniformity_eq p β).symm).replaceBornology fun s =>
Filter.ext_iff.1 (aux_cobounded_eq p β).symm sᶜ
instance [∀ i, MetricSpace (α i)] : MetricSpace (PiLp p α) :=
MetricSpace.ofT0PseudoMetricSpace _
theorem nndist_eq_sum {p : ℝ≥0∞} [Fact (1 ≤ p)] {β : ι → Type*} [∀ i, PseudoMetricSpace (β i)]
(hp : p ≠ ∞) (x y : PiLp p β) :
nndist x y = (∑ i : ι, nndist (x i) (y i) ^ p.toReal) ^ (1 / p.toReal) :=
-- Porting note: was `Subtype.ext`
NNReal.eq <| by
push_cast
exact dist_eq_sum (p.toReal_pos_iff_ne_top.mpr hp) _ _
#align pi_Lp.nndist_eq_sum PiLp.nndist_eq_sum
theorem nndist_eq_iSup {β : ι → Type*} [∀ i, PseudoMetricSpace (β i)] (x y : PiLp ∞ β) :
nndist x y = ⨆ i, nndist (x i) (y i) :=
-- Porting note: was `Subtype.ext`
NNReal.eq <| by
push_cast
exact dist_eq_iSup _ _
#align pi_Lp.nndist_eq_supr PiLp.nndist_eq_iSup
theorem lipschitzWith_equiv [∀ i, PseudoEMetricSpace (β i)] :
LipschitzWith 1 (WithLp.equiv p (∀ i, β i)) :=
lipschitzWith_equiv_aux p β
#align pi_Lp.lipschitz_with_equiv PiLp.lipschitzWith_equiv
theorem antilipschitzWith_equiv [∀ i, PseudoEMetricSpace (β i)] :
AntilipschitzWith ((Fintype.card ι : ℝ≥0) ^ (1 / p).toReal) (WithLp.equiv p (∀ i, β i)) :=
antilipschitzWith_equiv_aux p β
#align pi_Lp.antilipschitz_with_equiv PiLp.antilipschitzWith_equiv
theorem infty_equiv_isometry [∀ i, PseudoEMetricSpace (β i)] :
Isometry (WithLp.equiv ∞ (∀ i, β i)) :=
fun x y =>
le_antisymm (by simpa only [ENNReal.coe_one, one_mul] using lipschitzWith_equiv ∞ β x y)
(by
simpa only [ENNReal.div_top, ENNReal.zero_toReal, NNReal.rpow_zero, ENNReal.coe_one,
one_mul] using antilipschitzWith_equiv ∞ β x y)
#align pi_Lp.infty_equiv_isometry PiLp.infty_equiv_isometry
instance seminormedAddCommGroup [∀ i, SeminormedAddCommGroup (β i)] :
SeminormedAddCommGroup (PiLp p β) :=
{ Pi.addCommGroup with
dist_eq := fun x y => by
rcases p.dichotomy with (rfl | h)
· simp only [dist_eq_iSup, norm_eq_ciSup, dist_eq_norm, sub_apply]
· have : p ≠ ∞ := by
intro hp
rw [hp, ENNReal.top_toReal] at h
linarith
simp only [dist_eq_sum (zero_lt_one.trans_le h), norm_eq_sum (zero_lt_one.trans_le h),
dist_eq_norm, sub_apply] }
#align pi_Lp.seminormed_add_comm_group PiLp.seminormedAddCommGroup
instance normedAddCommGroup [∀ i, NormedAddCommGroup (α i)] : NormedAddCommGroup (PiLp p α) :=
{ PiLp.seminormedAddCommGroup p α with
eq_of_dist_eq_zero := eq_of_dist_eq_zero }
#align pi_Lp.normed_add_comm_group PiLp.normedAddCommGroup
theorem nnnorm_eq_sum {p : ℝ≥0∞} [Fact (1 ≤ p)] {β : ι → Type*} (hp : p ≠ ∞)
[∀ i, SeminormedAddCommGroup (β i)] (f : PiLp p β) :
‖f‖₊ = (∑ i, ‖f i‖₊ ^ p.toReal) ^ (1 / p.toReal) := by
ext
simp [NNReal.coe_sum, norm_eq_sum (p.toReal_pos_iff_ne_top.mpr hp)]
#align pi_Lp.nnnorm_eq_sum PiLp.nnnorm_eq_sum
section Linfty
variable {β}
variable [∀ i, SeminormedAddCommGroup (β i)]
| Mathlib/Analysis/NormedSpace/PiLp.lean | 593 | 595 | theorem nnnorm_eq_ciSup (f : PiLp ∞ β) : ‖f‖₊ = ⨆ i, ‖f i‖₊ := by |
ext
simp [NNReal.coe_iSup, norm_eq_ciSup]
|
import Mathlib.Algebra.BigOperators.Ring.List
import Mathlib.Data.Nat.ModEq
import Mathlib.Data.Nat.GCD.BigOperators
namespace Nat
variable {ι : Type*}
lemma modEq_list_prod_iff {a b} {l : List ℕ} (co : l.Pairwise Coprime) :
a ≡ b [MOD l.prod] ↔ ∀ i, a ≡ b [MOD l.get i] := by
induction' l with m l ih
· simp [modEq_one]
· have : Coprime m l.prod := coprime_list_prod_right_iff.mpr (List.pairwise_cons.mp co).1
simp only [List.prod_cons, ← modEq_and_modEq_iff_modEq_mul this, ih (List.Pairwise.of_cons co),
List.length_cons]
constructor
· rintro ⟨h0, hs⟩ i
cases i using Fin.cases <;> simp [h0, hs]
· intro h; exact ⟨h 0, fun i => h i.succ⟩
lemma modEq_list_prod_iff' {a b} {s : ι → ℕ} {l : List ι} (co : l.Pairwise (Coprime on s)) :
a ≡ b [MOD (l.map s).prod] ↔ ∀ i ∈ l, a ≡ b [MOD s i] := by
induction' l with i l ih
· simp [modEq_one]
· have : Coprime (s i) (l.map s).prod := by
simp only [coprime_list_prod_right_iff, List.mem_map, forall_exists_index, and_imp,
forall_apply_eq_imp_iff₂]
intro j hj
exact (List.pairwise_cons.mp co).1 j hj
simp [← modEq_and_modEq_iff_modEq_mul this, ih (List.Pairwise.of_cons co)]
variable (a s : ι → ℕ)
def chineseRemainderOfList : (l : List ι) → l.Pairwise (Coprime on s) →
{ k // ∀ i ∈ l, k ≡ a i [MOD s i] }
| [], _ => ⟨0, by simp⟩
| i :: l, co => by
have : Coprime (s i) (l.map s).prod := by
simp only [coprime_list_prod_right_iff, List.mem_map, forall_exists_index, and_imp,
forall_apply_eq_imp_iff₂]
intro j hj
exact (List.pairwise_cons.mp co).1 j hj
have ih := chineseRemainderOfList l co.of_cons
have k := chineseRemainder this (a i) ih
use k
simp only [List.mem_cons, forall_eq_or_imp, k.prop.1, true_and]
intro j hj
exact ((modEq_list_prod_iff' co.of_cons).mp k.prop.2 j hj).trans (ih.prop j hj)
@[simp] theorem chineseRemainderOfList_nil :
(chineseRemainderOfList a s [] List.Pairwise.nil : ℕ) = 0 := rfl
theorem chineseRemainderOfList_lt_prod (l : List ι)
(co : l.Pairwise (Coprime on s)) (hs : ∀ i ∈ l, s i ≠ 0) :
chineseRemainderOfList a s l co < (l.map s).prod := by
cases l with
| nil => simp
| cons i l =>
simp only [chineseRemainderOfList, List.map_cons, List.prod_cons]
have : Coprime (s i) (l.map s).prod := by
simp only [coprime_list_prod_right_iff, List.mem_map, forall_exists_index, and_imp,
forall_apply_eq_imp_iff₂]
intro j hj
exact (List.pairwise_cons.mp co).1 j hj
refine chineseRemainder_lt_mul this (a i) (chineseRemainderOfList a s l co.of_cons)
(hs i (List.mem_cons_self _ l)) ?_
simp only [ne_eq, List.prod_eq_zero_iff, List.mem_map, not_exists, not_and]
intro j hj
exact hs j (List.mem_cons_of_mem _ hj)
theorem chineseRemainderOfList_modEq_unique (l : List ι)
(co : l.Pairwise (Coprime on s)) {z} (hz : ∀ i ∈ l, z ≡ a i [MOD s i]) :
z ≡ chineseRemainderOfList a s l co [MOD (l.map s).prod] := by
induction' l with i l ih
· simp [modEq_one]
· simp only [List.map_cons, List.prod_cons, chineseRemainderOfList]
have : Coprime (s i) (l.map s).prod := by
simp only [coprime_list_prod_right_iff, List.mem_map, forall_exists_index, and_imp,
forall_apply_eq_imp_iff₂]
intro j hj
exact (List.pairwise_cons.mp co).1 j hj
exact chineseRemainder_modEq_unique this
(hz i (List.mem_cons_self _ _)) (ih co.of_cons (fun j hj => hz j (List.mem_cons_of_mem _ hj)))
| Mathlib/Data/Nat/ChineseRemainder.lean | 107 | 118 | theorem chineseRemainderOfList_perm {l l' : List ι} (hl : l.Perm l')
(hs : ∀ i ∈ l, s i ≠ 0) (co : l.Pairwise (Coprime on s)) :
(chineseRemainderOfList a s l co : ℕ) =
chineseRemainderOfList a s l' (co.perm hl coprime_comm.mpr) := by |
let z := chineseRemainderOfList a s l' (co.perm hl coprime_comm.mpr)
have hlp : (l.map s).prod = (l'.map s).prod := List.Perm.prod_eq (List.Perm.map s hl)
exact (chineseRemainderOfList_modEq_unique a s l co (z := z)
(fun i hi => z.prop i (hl.symm.mem_iff.mpr hi))).symm.eq_of_lt_of_lt
(chineseRemainderOfList_lt_prod _ _ _ _ hs)
(by rw [hlp]
exact chineseRemainderOfList_lt_prod _ _ _ _
(by simpa [List.Perm.mem_iff hl.symm] using hs))
|
import Mathlib.Topology.Algebra.InfiniteSum.Group
import Mathlib.Topology.Algebra.Star
noncomputable section
open Filter Finset Function
open scoped Topology
variable {α β γ δ : Type*}
section ContinuousMul
variable [CommMonoid α] [TopologicalSpace α] [ContinuousMul α]
section CompleteSpace
variable [CommGroup α] [UniformSpace α] [UniformGroup α] [CompleteSpace α]
@[to_additive]
theorem Multipliable.sigma_factor {γ : β → Type*} {f : (Σb : β, γ b) → α}
(ha : Multipliable f) (b : β) :
Multipliable fun c ↦ f ⟨b, c⟩ :=
ha.comp_injective sigma_mk_injective
#align summable.sigma_factor Summable.sigma_factor
@[to_additive]
theorem Multipliable.sigma {γ : β → Type*} {f : (Σb : β, γ b) → α} (ha : Multipliable f) :
Multipliable fun b ↦ ∏' c, f ⟨b, c⟩ :=
ha.sigma' fun b ↦ ha.sigma_factor b
#align summable.sigma Summable.sigma
@[to_additive Summable.prod_factor]
theorem Multipliable.prod_factor {f : β × γ → α} (h : Multipliable f) (b : β) :
Multipliable fun c ↦ f (b, c) :=
h.comp_injective fun _ _ h ↦ (Prod.ext_iff.1 h).2
#align summable.prod_factor Summable.prod_factor
@[to_additive]
lemma HasProd.tprod_fiberwise [T2Space α] {f : β → α} {a : α} (hf : HasProd f a) (g : β → γ) :
HasProd (fun c : γ ↦ ∏' b : g ⁻¹' {c}, f b) a :=
(((Equiv.sigmaFiberEquiv g).hasProd_iff).mpr hf).sigma <|
fun _ ↦ ((hf.multipliable.subtype _).hasProd_iff).mpr rfl
section ContinuousStar
variable [AddCommMonoid α] [TopologicalSpace α] [StarAddMonoid α] [ContinuousStar α] {f : β → α}
{a : α}
theorem HasSum.star (h : HasSum f a) : HasSum (fun b ↦ star (f b)) (star a) := by
simpa only using h.map (starAddEquiv : α ≃+ α) continuous_star
#align has_sum.star HasSum.star
theorem Summable.star (hf : Summable f) : Summable fun b ↦ star (f b) :=
hf.hasSum.star.summable
#align summable.star Summable.star
theorem Summable.ofStar (hf : Summable fun b ↦ Star.star (f b)) : Summable f := by
simpa only [star_star] using hf.star
#align summable.of_star Summable.ofStar
@[simp]
theorem summable_star_iff : (Summable fun b ↦ star (f b)) ↔ Summable f :=
⟨Summable.ofStar, Summable.star⟩
#align summable_star_iff summable_star_iff
@[simp]
theorem summable_star_iff' : Summable (star f) ↔ Summable f :=
summable_star_iff
#align summable_star_iff' summable_star_iff'
| Mathlib/Topology/Algebra/InfiniteSum/Constructions.lean | 328 | 332 | theorem tsum_star [T2Space α] : star (∑' b, f b) = ∑' b, star (f b) := by |
by_cases hf : Summable f
· exact hf.hasSum.star.tsum_eq.symm
· rw [tsum_eq_zero_of_not_summable hf, tsum_eq_zero_of_not_summable (mt Summable.ofStar hf),
star_zero]
|
import Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff
import Mathlib.FieldTheory.Finite.Basic
import Mathlib.Data.Matrix.CharP
#align_import linear_algebra.matrix.charpoly.finite_field from "leanprover-community/mathlib"@"b95b8c7a484a298228805c72c142f6b062eb0d70"
noncomputable section
open Polynomial Matrix
open scoped Polynomial
variable {n : Type*} [DecidableEq n] [Fintype n]
@[simp]
theorem FiniteField.Matrix.charpoly_pow_card {K : Type*} [Field K] [Fintype K] (M : Matrix n n K) :
(M ^ Fintype.card K).charpoly = M.charpoly := by
cases (isEmpty_or_nonempty n).symm
· cases' CharP.exists K with p hp; letI := hp
rcases FiniteField.card K p with ⟨⟨k, kpos⟩, ⟨hp, hk⟩⟩
haveI : Fact p.Prime := ⟨hp⟩
dsimp at hk; rw [hk]
apply (frobenius_inj K[X] p).iterate k
repeat' rw [iterate_frobenius (R := K[X])]; rw [← hk]
rw [← FiniteField.expand_card]
unfold charpoly
rw [AlgHom.map_det, ← coe_detMonoidHom, ← (detMonoidHom : Matrix n n K[X] →* K[X]).map_pow]
apply congr_arg det
refine matPolyEquiv.injective ?_
rw [AlgEquiv.map_pow, matPolyEquiv_charmatrix, hk, sub_pow_char_pow_of_commute, ← C_pow]
· exact (id (matPolyEquiv_eq_X_pow_sub_C (p ^ k) M) : _)
· exact (C M).commute_X
· exact congr_arg _ (Subsingleton.elim _ _)
#align finite_field.matrix.charpoly_pow_card FiniteField.Matrix.charpoly_pow_card
@[simp]
theorem ZMod.charpoly_pow_card {p : ℕ} [Fact p.Prime] (M : Matrix n n (ZMod p)) :
(M ^ p).charpoly = M.charpoly := by
have h := FiniteField.Matrix.charpoly_pow_card M
rwa [ZMod.card] at h
#align zmod.charpoly_pow_card ZMod.charpoly_pow_card
| Mathlib/LinearAlgebra/Matrix/Charpoly/FiniteField.lean | 53 | 58 | theorem FiniteField.trace_pow_card {K : Type*} [Field K] [Fintype K] (M : Matrix n n K) :
trace (M ^ Fintype.card K) = trace M ^ Fintype.card K := by |
cases isEmpty_or_nonempty n
· simp [Matrix.trace]
rw [Matrix.trace_eq_neg_charpoly_coeff, Matrix.trace_eq_neg_charpoly_coeff,
FiniteField.Matrix.charpoly_pow_card, FiniteField.pow_card]
|
import Mathlib.Analysis.Convex.StrictConvexBetween
import Mathlib.Geometry.Euclidean.Basic
#align_import geometry.euclidean.sphere.basic from "leanprover-community/mathlib"@"46b633fd842bef9469441c0209906f6dddd2b4f5"
noncomputable section
open RealInnerProductSpace
namespace EuclideanGeometry
variable {V : Type*} (P : Type*)
open FiniteDimensional
@[ext]
structure Sphere [MetricSpace P] where
center : P
radius : ℝ
#align euclidean_geometry.sphere EuclideanGeometry.Sphere
variable {P}
section MetricSpace
variable [MetricSpace P]
instance [Nonempty P] : Nonempty (Sphere P) :=
⟨⟨Classical.arbitrary P, 0⟩⟩
instance : Coe (Sphere P) (Set P) :=
⟨fun s => Metric.sphere s.center s.radius⟩
instance : Membership P (Sphere P) :=
⟨fun p s => p ∈ (s : Set P)⟩
theorem Sphere.mk_center (c : P) (r : ℝ) : (⟨c, r⟩ : Sphere P).center = c :=
rfl
#align euclidean_geometry.sphere.mk_center EuclideanGeometry.Sphere.mk_center
theorem Sphere.mk_radius (c : P) (r : ℝ) : (⟨c, r⟩ : Sphere P).radius = r :=
rfl
#align euclidean_geometry.sphere.mk_radius EuclideanGeometry.Sphere.mk_radius
@[simp]
| Mathlib/Geometry/Euclidean/Sphere/Basic.lean | 74 | 75 | theorem Sphere.mk_center_radius (s : Sphere P) : (⟨s.center, s.radius⟩ : Sphere P) = s := by |
ext <;> rfl
|
import Mathlib.SetTheory.Ordinal.Arithmetic
import Mathlib.Tactic.Abel
#align_import set_theory.ordinal.natural_ops from "leanprover-community/mathlib"@"31b269b60935483943542d547a6dd83a66b37dc7"
set_option autoImplicit true
universe u v
open Function Order
noncomputable section
def NatOrdinal : Type _ :=
-- Porting note: used to derive LinearOrder & SuccOrder but need to manually define
Ordinal deriving Zero, Inhabited, One, WellFoundedRelation
#align nat_ordinal NatOrdinal
instance NatOrdinal.linearOrder : LinearOrder NatOrdinal := {Ordinal.linearOrder with}
instance NatOrdinal.succOrder : SuccOrder NatOrdinal := {Ordinal.succOrder with}
@[match_pattern]
def Ordinal.toNatOrdinal : Ordinal ≃o NatOrdinal :=
OrderIso.refl _
#align ordinal.to_nat_ordinal Ordinal.toNatOrdinal
@[match_pattern]
def NatOrdinal.toOrdinal : NatOrdinal ≃o Ordinal :=
OrderIso.refl _
#align nat_ordinal.to_ordinal NatOrdinal.toOrdinal
open NatOrdinal
open NaturalOps
namespace Ordinal
theorem nadd_eq_add (a b : Ordinal) : a ♯ b = toOrdinal (toNatOrdinal a + toNatOrdinal b) :=
rfl
#align ordinal.nadd_eq_add Ordinal.nadd_eq_add
@[simp]
theorem toNatOrdinal_cast_nat (n : ℕ) : toNatOrdinal n = n := by
rw [← toOrdinal_cast_nat n]
rfl
#align ordinal.to_nat_ordinal_cast_nat Ordinal.toNatOrdinal_cast_nat
theorem lt_of_nadd_lt_nadd_left : ∀ {a b c}, a ♯ b < a ♯ c → b < c :=
@lt_of_add_lt_add_left NatOrdinal _ _ _
#align ordinal.lt_of_nadd_lt_nadd_left Ordinal.lt_of_nadd_lt_nadd_left
theorem lt_of_nadd_lt_nadd_right : ∀ {a b c}, b ♯ a < c ♯ a → b < c :=
@lt_of_add_lt_add_right NatOrdinal _ _ _
#align ordinal.lt_of_nadd_lt_nadd_right Ordinal.lt_of_nadd_lt_nadd_right
theorem le_of_nadd_le_nadd_left : ∀ {a b c}, a ♯ b ≤ a ♯ c → b ≤ c :=
@le_of_add_le_add_left NatOrdinal _ _ _
#align ordinal.le_of_nadd_le_nadd_left Ordinal.le_of_nadd_le_nadd_left
theorem le_of_nadd_le_nadd_right : ∀ {a b c}, b ♯ a ≤ c ♯ a → b ≤ c :=
@le_of_add_le_add_right NatOrdinal _ _ _
#align ordinal.le_of_nadd_le_nadd_right Ordinal.le_of_nadd_le_nadd_right
theorem nadd_lt_nadd_iff_left : ∀ (a) {b c}, a ♯ b < a ♯ c ↔ b < c :=
@add_lt_add_iff_left NatOrdinal _ _ _ _
#align ordinal.nadd_lt_nadd_iff_left Ordinal.nadd_lt_nadd_iff_left
theorem nadd_lt_nadd_iff_right : ∀ (a) {b c}, b ♯ a < c ♯ a ↔ b < c :=
@add_lt_add_iff_right NatOrdinal _ _ _ _
#align ordinal.nadd_lt_nadd_iff_right Ordinal.nadd_lt_nadd_iff_right
theorem nadd_le_nadd_iff_left : ∀ (a) {b c}, a ♯ b ≤ a ♯ c ↔ b ≤ c :=
@add_le_add_iff_left NatOrdinal _ _ _ _
#align ordinal.nadd_le_nadd_iff_left Ordinal.nadd_le_nadd_iff_left
theorem nadd_le_nadd_iff_right : ∀ (a) {b c}, b ♯ a ≤ c ♯ a ↔ b ≤ c :=
@_root_.add_le_add_iff_right NatOrdinal _ _ _ _
#align ordinal.nadd_le_nadd_iff_right Ordinal.nadd_le_nadd_iff_right
theorem nadd_le_nadd : ∀ {a b c d}, a ≤ b → c ≤ d → a ♯ c ≤ b ♯ d :=
@add_le_add NatOrdinal _ _ _ _
#align ordinal.nadd_le_nadd Ordinal.nadd_le_nadd
theorem nadd_lt_nadd : ∀ {a b c d}, a < b → c < d → a ♯ c < b ♯ d :=
@add_lt_add NatOrdinal _ _ _ _
#align ordinal.nadd_lt_nadd Ordinal.nadd_lt_nadd
theorem nadd_lt_nadd_of_lt_of_le : ∀ {a b c d}, a < b → c ≤ d → a ♯ c < b ♯ d :=
@add_lt_add_of_lt_of_le NatOrdinal _ _ _ _
#align ordinal.nadd_lt_nadd_of_lt_of_le Ordinal.nadd_lt_nadd_of_lt_of_le
theorem nadd_lt_nadd_of_le_of_lt : ∀ {a b c d}, a ≤ b → c < d → a ♯ c < b ♯ d :=
@add_lt_add_of_le_of_lt NatOrdinal _ _ _ _
#align ordinal.nadd_lt_nadd_of_le_of_lt Ordinal.nadd_lt_nadd_of_le_of_lt
theorem nadd_left_cancel : ∀ {a b c}, a ♯ b = a ♯ c → b = c :=
@_root_.add_left_cancel NatOrdinal _ _
#align ordinal.nadd_left_cancel Ordinal.nadd_left_cancel
theorem nadd_right_cancel : ∀ {a b c}, a ♯ b = c ♯ b → a = c :=
@_root_.add_right_cancel NatOrdinal _ _
#align ordinal.nadd_right_cancel Ordinal.nadd_right_cancel
theorem nadd_left_cancel_iff : ∀ {a b c}, a ♯ b = a ♯ c ↔ b = c :=
@add_left_cancel_iff NatOrdinal _ _
#align ordinal.nadd_left_cancel_iff Ordinal.nadd_left_cancel_iff
theorem nadd_right_cancel_iff : ∀ {a b c}, b ♯ a = c ♯ a ↔ b = c :=
@add_right_cancel_iff NatOrdinal _ _
#align ordinal.nadd_right_cancel_iff Ordinal.nadd_right_cancel_iff
theorem le_nadd_self {a b} : a ≤ b ♯ a := by simpa using nadd_le_nadd_right (Ordinal.zero_le b) a
#align ordinal.le_nadd_self Ordinal.le_nadd_self
theorem le_nadd_left {a b c} (h : a ≤ c) : a ≤ b ♯ c :=
le_nadd_self.trans (nadd_le_nadd_left h b)
#align ordinal.le_nadd_left Ordinal.le_nadd_left
theorem le_self_nadd {a b} : a ≤ a ♯ b := by simpa using nadd_le_nadd_left (Ordinal.zero_le b) a
#align ordinal.le_self_nadd Ordinal.le_self_nadd
theorem le_nadd_right {a b c} (h : a ≤ b) : a ≤ b ♯ c :=
le_self_nadd.trans (nadd_le_nadd_right h c)
#align ordinal.le_nadd_right Ordinal.le_nadd_right
theorem nadd_left_comm : ∀ a b c, a ♯ (b ♯ c) = b ♯ (a ♯ c) :=
@add_left_comm NatOrdinal _
#align ordinal.nadd_left_comm Ordinal.nadd_left_comm
theorem nadd_right_comm : ∀ a b c, a ♯ b ♯ c = a ♯ c ♯ b :=
@add_right_comm NatOrdinal _
#align ordinal.nadd_right_comm Ordinal.nadd_right_comm
variable {a b c d : Ordinal.{u}}
theorem nmul_def (a b : Ordinal) :
a ⨳ b = sInf {c | ∀ a' < a, ∀ b' < b, a' ⨳ b ♯ a ⨳ b' < c ♯ a' ⨳ b'} := by rw [nmul]
#align ordinal.nmul_def Ordinal.nmul_def
theorem nmul_nonempty (a b : Ordinal.{u}) :
{c : Ordinal.{u} | ∀ a' < a, ∀ b' < b, a' ⨳ b ♯ a ⨳ b' < c ♯ a' ⨳ b'}.Nonempty :=
⟨_, fun _ ha _ hb => (lt_blsub₂.{u, u, u} _ ha hb).trans_le le_self_nadd⟩
#align ordinal.nmul_nonempty Ordinal.nmul_nonempty
theorem nmul_nadd_lt {a' b' : Ordinal} (ha : a' < a) (hb : b' < b) :
a' ⨳ b ♯ a ⨳ b' < a ⨳ b ♯ a' ⨳ b' := by
rw [nmul_def a b]
exact csInf_mem (nmul_nonempty a b) a' ha b' hb
#align ordinal.nmul_nadd_lt Ordinal.nmul_nadd_lt
theorem nmul_nadd_le {a' b' : Ordinal} (ha : a' ≤ a) (hb : b' ≤ b) :
a' ⨳ b ♯ a ⨳ b' ≤ a ⨳ b ♯ a' ⨳ b' := by
rcases lt_or_eq_of_le ha with (ha | rfl)
· rcases lt_or_eq_of_le hb with (hb | rfl)
· exact (nmul_nadd_lt ha hb).le
· rw [nadd_comm]
· exact le_rfl
#align ordinal.nmul_nadd_le Ordinal.nmul_nadd_le
theorem lt_nmul_iff : c < a ⨳ b ↔ ∃ a' < a, ∃ b' < b, c ♯ a' ⨳ b' ≤ a' ⨳ b ♯ a ⨳ b' := by
refine ⟨fun h => ?_, ?_⟩
· rw [nmul] at h
simpa using not_mem_of_lt_csInf h ⟨0, fun _ _ => bot_le⟩
· rintro ⟨a', ha, b', hb, h⟩
have := h.trans_lt (nmul_nadd_lt ha hb)
rwa [nadd_lt_nadd_iff_right] at this
#align ordinal.lt_nmul_iff Ordinal.lt_nmul_iff
theorem nmul_le_iff : a ⨳ b ≤ c ↔ ∀ a' < a, ∀ b' < b, a' ⨳ b ♯ a ⨳ b' < c ♯ a' ⨳ b' := by
rw [← not_iff_not]; simp [lt_nmul_iff]
#align ordinal.nmul_le_iff Ordinal.nmul_le_iff
theorem nmul_comm : ∀ a b, a ⨳ b = b ⨳ a
| a, b => by
rw [nmul, nmul]
congr; ext x; constructor <;> intro H c hc d hd
-- Porting note: had to add additional arguments to `nmul_comm` here
-- for the termination checker.
· rw [nadd_comm, ← nmul_comm d b, ← nmul_comm a c, ← nmul_comm d]
exact H _ hd _ hc
· rw [nadd_comm, nmul_comm a d, nmul_comm c, nmul_comm c]
exact H _ hd _ hc
termination_by a b => (a, b)
#align ordinal.nmul_comm Ordinal.nmul_comm
@[simp]
theorem nmul_zero (a) : a ⨳ 0 = 0 := by
rw [← Ordinal.le_zero, nmul_le_iff]
exact fun _ _ a ha => (Ordinal.not_lt_zero a ha).elim
#align ordinal.nmul_zero Ordinal.nmul_zero
@[simp]
theorem zero_nmul (a) : 0 ⨳ a = 0 := by rw [nmul_comm, nmul_zero]
#align ordinal.zero_nmul Ordinal.zero_nmul
@[simp]
theorem nmul_one (a : Ordinal) : a ⨳ 1 = a := by
rw [nmul]
simp only [lt_one_iff_zero, forall_eq, nmul_zero, nadd_zero]
convert csInf_Ici (α := Ordinal)
ext b
-- Porting note: added this `simp` line, as the result from `convert`
-- is slightly different.
simp only [Set.mem_setOf_eq, Set.mem_Ici]
refine ⟨fun H => le_of_forall_lt fun c hc => ?_, fun ha c hc => ?_⟩
-- Porting note: had to add arguments to `nmul_one` in the next two lines
-- for the termination checker.
· simpa only [nmul_one c] using H c hc
· simpa only [nmul_one c] using hc.trans_le ha
termination_by a
#align ordinal.nmul_one Ordinal.nmul_one
@[simp]
theorem one_nmul (a) : 1 ⨳ a = a := by rw [nmul_comm, nmul_one]
#align ordinal.one_nmul Ordinal.one_nmul
theorem nmul_lt_nmul_of_pos_left (h₁ : a < b) (h₂ : 0 < c) : c ⨳ a < c ⨳ b :=
lt_nmul_iff.2 ⟨0, h₂, a, h₁, by simp⟩
#align ordinal.nmul_lt_nmul_of_pos_left Ordinal.nmul_lt_nmul_of_pos_left
theorem nmul_lt_nmul_of_pos_right (h₁ : a < b) (h₂ : 0 < c) : a ⨳ c < b ⨳ c :=
lt_nmul_iff.2 ⟨a, h₁, 0, h₂, by simp⟩
#align ordinal.nmul_lt_nmul_of_pos_right Ordinal.nmul_lt_nmul_of_pos_right
theorem nmul_le_nmul_of_nonneg_left (h₁ : a ≤ b) (h₂ : 0 ≤ c) : c ⨳ a ≤ c ⨳ b := by
rcases lt_or_eq_of_le h₁ with (h₁ | rfl) <;> rcases lt_or_eq_of_le h₂ with (h₂ | rfl)
· exact (nmul_lt_nmul_of_pos_left h₁ h₂).le
all_goals simp
#align ordinal.nmul_le_nmul_of_nonneg_left Ordinal.nmul_le_nmul_of_nonneg_left
theorem nmul_le_nmul_of_nonneg_right (h₁ : a ≤ b) (h₂ : 0 ≤ c) : a ⨳ c ≤ b ⨳ c := by
rw [nmul_comm, nmul_comm b]
exact nmul_le_nmul_of_nonneg_left h₁ h₂
#align ordinal.nmul_le_nmul_of_nonneg_right Ordinal.nmul_le_nmul_of_nonneg_right
theorem nmul_nadd : ∀ a b c, a ⨳ (b ♯ c) = a ⨳ b ♯ a ⨳ c
| a, b, c => by
refine le_antisymm (nmul_le_iff.2 fun a' ha d hd => ?_)
(nadd_le_iff.2 ⟨fun d hd => ?_, fun d hd => ?_⟩)
· -- Porting note: adding arguments to `nmul_nadd` for the termination checker.
rw [nmul_nadd a' b c]
rcases lt_nadd_iff.1 hd with (⟨b', hb, hd⟩ | ⟨c', hc, hd⟩)
· have := nadd_lt_nadd_of_lt_of_le (nmul_nadd_lt ha hb) (nmul_nadd_le ha.le hd)
-- Porting note: adding arguments to `nmul_nadd` for the termination checker.
rw [nmul_nadd a' b' c, nmul_nadd a b' c] at this
simp only [nadd_assoc] at this
rwa [nadd_left_comm, nadd_left_comm _ (a ⨳ b'), nadd_left_comm (a ⨳ b),
nadd_lt_nadd_iff_left, nadd_left_comm (a' ⨳ b), nadd_left_comm (a ⨳ b),
nadd_lt_nadd_iff_left, ← nadd_assoc, ← nadd_assoc] at this
· have := nadd_lt_nadd_of_le_of_lt (nmul_nadd_le ha.le hd) (nmul_nadd_lt ha hc)
-- Porting note: adding arguments to `nmul_nadd` for the termination checker.
rw [nmul_nadd a' b c', nmul_nadd a b c'] at this
simp only [nadd_assoc] at this
rwa [nadd_left_comm, nadd_comm (a ⨳ c), nadd_left_comm (a' ⨳ d), nadd_left_comm (a ⨳ c'),
nadd_left_comm (a ⨳ b), nadd_lt_nadd_iff_left, nadd_comm (a' ⨳ c), nadd_left_comm (a ⨳ d),
nadd_left_comm (a' ⨳ b), nadd_left_comm (a ⨳ b), nadd_lt_nadd_iff_left, nadd_comm (a ⨳ d),
nadd_comm (a' ⨳ d), ← nadd_assoc, ← nadd_assoc] at this
· rcases lt_nmul_iff.1 hd with ⟨a', ha, b', hb, hd⟩
have := nadd_lt_nadd_of_le_of_lt hd (nmul_nadd_lt ha (nadd_lt_nadd_right hb c))
-- Porting note: adding arguments to `nmul_nadd` for the termination checker.
rw [nmul_nadd a' b c, nmul_nadd a b' c, nmul_nadd a'] at this
simp only [nadd_assoc] at this
rwa [nadd_left_comm (a' ⨳ b'), nadd_left_comm, nadd_lt_nadd_iff_left, nadd_left_comm,
nadd_left_comm _ (a' ⨳ b'), nadd_left_comm (a ⨳ b'), nadd_lt_nadd_iff_left,
nadd_left_comm (a' ⨳ c), nadd_left_comm, nadd_lt_nadd_iff_left, nadd_left_comm,
nadd_comm _ (a' ⨳ c), nadd_lt_nadd_iff_left] at this
· rcases lt_nmul_iff.1 hd with ⟨a', ha, c', hc, hd⟩
have := nadd_lt_nadd_of_lt_of_le (nmul_nadd_lt ha (nadd_lt_nadd_left hc b)) hd
-- Porting note: adding arguments to `nmul_nadd` for the termination checker.
rw [nmul_nadd a' b c, nmul_nadd a b c', nmul_nadd a'] at this
simp only [nadd_assoc] at this
rwa [nadd_left_comm _ (a' ⨳ b), nadd_lt_nadd_iff_left, nadd_left_comm (a' ⨳ c'),
nadd_left_comm _ (a' ⨳ c), nadd_lt_nadd_iff_left, nadd_left_comm, nadd_comm (a' ⨳ c'),
nadd_left_comm _ (a ⨳ c'), nadd_lt_nadd_iff_left, nadd_comm _ (a' ⨳ c'),
nadd_comm _ (a' ⨳ c'), nadd_left_comm, nadd_lt_nadd_iff_left] at this
termination_by a b c => (a, b, c)
#align ordinal.nmul_nadd Ordinal.nmul_nadd
theorem nadd_nmul (a b c) : (a ♯ b) ⨳ c = a ⨳ c ♯ b ⨳ c := by
rw [nmul_comm, nmul_nadd, nmul_comm, nmul_comm c]
#align ordinal.nadd_nmul Ordinal.nadd_nmul
theorem nmul_nadd_lt₃ {a' b' c' : Ordinal} (ha : a' < a) (hb : b' < b) (hc : c' < c) :
a' ⨳ b ⨳ c ♯ a ⨳ b' ⨳ c ♯ a ⨳ b ⨳ c' ♯ a' ⨳ b' ⨳ c' <
a ⨳ b ⨳ c ♯ a' ⨳ b' ⨳ c ♯ a' ⨳ b ⨳ c' ♯ a ⨳ b' ⨳ c' := by
simpa only [nadd_nmul, ← nadd_assoc] using nmul_nadd_lt (nmul_nadd_lt ha hb) hc
#align ordinal.nmul_nadd_lt₃ Ordinal.nmul_nadd_lt₃
theorem nmul_nadd_le₃ {a' b' c' : Ordinal} (ha : a' ≤ a) (hb : b' ≤ b) (hc : c' ≤ c) :
a' ⨳ b ⨳ c ♯ a ⨳ b' ⨳ c ♯ a ⨳ b ⨳ c' ♯ a' ⨳ b' ⨳ c' ≤
a ⨳ b ⨳ c ♯ a' ⨳ b' ⨳ c ♯ a' ⨳ b ⨳ c' ♯ a ⨳ b' ⨳ c' := by
simpa only [nadd_nmul, ← nadd_assoc] using nmul_nadd_le (nmul_nadd_le ha hb) hc
#align ordinal.nmul_nadd_le₃ Ordinal.nmul_nadd_le₃
| Mathlib/SetTheory/Ordinal/NaturalOps.lean | 673 | 678 | theorem nmul_nadd_lt₃' {a' b' c' : Ordinal} (ha : a' < a) (hb : b' < b) (hc : c' < c) :
a' ⨳ (b ⨳ c) ♯ a ⨳ (b' ⨳ c) ♯ a ⨳ (b ⨳ c') ♯ a' ⨳ (b' ⨳ c') <
a ⨳ (b ⨳ c) ♯ a' ⨳ (b' ⨳ c) ♯ a' ⨳ (b ⨳ c') ♯ a ⨳ (b' ⨳ c') := by |
simp only [nmul_comm _ (_ ⨳ _)]
convert nmul_nadd_lt₃ hb hc ha using 1 <;>
· simp only [nadd_eq_add, NatOrdinal.toOrdinal_toNatOrdinal]; abel_nf
|
import Mathlib.Analysis.SpecialFunctions.Trigonometric.Bounds
#align_import data.real.pi.bounds from "leanprover-community/mathlib"@"402f8982dddc1864bd703da2d6e2ee304a866973"
-- Porting note: needed to add a lot of type ascriptions for lean to interpret numbers as reals.
open scoped Real
namespace Real
theorem pi_gt_sqrtTwoAddSeries (n : ℕ) :
(2 : ℝ) ^ (n + 1) * √(2 - sqrtTwoAddSeries 0 n) < π := by
have : √(2 - sqrtTwoAddSeries 0 n) / (2 : ℝ) * (2 : ℝ) ^ (n + 2) < π := by
rw [← lt_div_iff, ← sin_pi_over_two_pow_succ]
focus
apply sin_lt
apply div_pos pi_pos
all_goals apply pow_pos; norm_num
apply lt_of_le_of_lt (le_of_eq _) this
rw [pow_succ' _ (n + 1), ← mul_assoc, div_mul_cancel₀, mul_comm]; norm_num
#align real.pi_gt_sqrt_two_add_series Real.pi_gt_sqrtTwoAddSeries
| Mathlib/Data/Real/Pi/Bounds.lean | 40 | 71 | theorem pi_lt_sqrtTwoAddSeries (n : ℕ) :
π < (2 : ℝ) ^ (n + 1) * √(2 - sqrtTwoAddSeries 0 n) + 1 / (4 : ℝ) ^ n := by |
have : π <
(√(2 - sqrtTwoAddSeries 0 n) / (2 : ℝ) + (1 : ℝ) / ((2 : ℝ) ^ n) ^ 3 / 4) *
(2 : ℝ) ^ (n + 2) := by
rw [← div_lt_iff (by norm_num), ← sin_pi_over_two_pow_succ]
refine lt_of_lt_of_le (lt_add_of_sub_right_lt (sin_gt_sub_cube ?_ ?_)) ?_
· apply div_pos pi_pos; apply pow_pos; norm_num
· rw [div_le_iff']
· refine le_trans pi_le_four ?_
simp only [show (4 : ℝ) = (2 : ℝ) ^ 2 by norm_num, mul_one]
apply pow_le_pow_right (by norm_num)
apply le_add_of_nonneg_left; apply Nat.zero_le
· apply pow_pos; norm_num
apply add_le_add_left; rw [div_le_div_right (by norm_num)]
rw [le_div_iff (by norm_num), ← mul_pow]
refine le_trans ?_ (le_of_eq (one_pow 3)); apply pow_le_pow_left
· apply le_of_lt; apply mul_pos
· apply div_pos pi_pos; apply pow_pos; norm_num
· apply pow_pos; norm_num
· rw [← le_div_iff (by norm_num)]
refine le_trans ((div_le_div_right ?_).mpr pi_le_four) ?_
· apply pow_pos; norm_num
· simp only [pow_succ', ← div_div, one_div]
-- Porting note: removed `convert le_rfl`
norm_num
apply lt_of_lt_of_le this (le_of_eq _); rw [add_mul]; congr 1
· ring
simp only [show (4 : ℝ) = 2 ^ 2 by norm_num, ← pow_mul, div_div, ← pow_add]
rw [one_div, one_div, inv_mul_eq_iff_eq_mul₀, eq_comm, mul_inv_eq_iff_eq_mul₀, ← pow_add]
· rw [add_assoc, Nat.mul_succ, add_comm, add_comm n, add_assoc, mul_comm n]
all_goals norm_num
|
import Mathlib.Algebra.Field.Defs
import Mathlib.Algebra.Ring.Int
#align_import algebra.field.power from "leanprover-community/mathlib"@"1e05171a5e8cf18d98d9cf7b207540acb044acae"
variable {α : Type*}
section DivisionRing
variable [DivisionRing α] {n : ℤ}
| Mathlib/Algebra/Field/Power.lean | 26 | 30 | theorem Odd.neg_zpow (h : Odd n) (a : α) : (-a) ^ n = -a ^ n := by |
have hn : n ≠ 0 := by rintro rfl; exact Int.odd_iff_not_even.1 h even_zero
obtain ⟨k, rfl⟩ := h
simp_rw [zpow_add' (.inr (.inl hn)), zpow_one, zpow_mul, zpow_two, neg_mul_neg,
neg_mul_eq_mul_neg]
|
import Mathlib.CategoryTheory.Adjunction.Whiskering
import Mathlib.CategoryTheory.Sites.PreservesSheafification
#align_import category_theory.sites.adjunction from "leanprover-community/mathlib"@"70fd9563a21e7b963887c9360bd29b2393e6225a"
namespace CategoryTheory
open GrothendieckTopology CategoryTheory Limits Opposite
universe v u
variable {C : Type u} [Category.{v} C] (J : GrothendieckTopology C)
variable {D : Type*} [Category D]
variable {E : Type*} [Category E]
variable {F : D ⥤ E} {G : E ⥤ D}
variable [HasWeakSheafify J D]
abbrev sheafForget [ConcreteCategory D] [HasSheafCompose J (forget D)] :
Sheaf J D ⥤ SheafOfTypes J :=
sheafCompose J (forget D) ⋙ (sheafEquivSheafOfTypes J).functor
set_option linter.uppercaseLean3 false in
#align category_theory.Sheaf_forget CategoryTheory.sheafForget
namespace Sheaf
noncomputable section
@[simps]
def composeEquiv [HasSheafCompose J F] (adj : G ⊣ F) (X : Sheaf J E) (Y : Sheaf J D) :
((composeAndSheafify J G).obj X ⟶ Y) ≃ (X ⟶ (sheafCompose J F).obj Y) :=
let A := adj.whiskerRight Cᵒᵖ
{ toFun := fun η => ⟨A.homEquiv _ _ (toSheafify J _ ≫ η.val)⟩
invFun := fun γ => ⟨sheafifyLift J ((A.homEquiv _ _).symm ((sheafToPresheaf _ _).map γ)) Y.2⟩
left_inv := by
intro η
ext1
dsimp
symm
apply sheafifyLift_unique
rw [Equiv.symm_apply_apply]
right_inv := by
intro γ
ext1
dsimp
-- This used to be `rw`, but we need `erw` after leanprover/lean4#2644
erw [toSheafify_sheafifyLift, Equiv.apply_symm_apply] }
set_option linter.uppercaseLean3 false in
#align category_theory.Sheaf.compose_equiv CategoryTheory.Sheaf.composeEquiv
-- These lemmas have always been bad (#7657), but leanprover/lean4#2644 made `simp` start noticing
attribute [nolint simpNF] CategoryTheory.Sheaf.composeEquiv_apply_val
CategoryTheory.Sheaf.composeEquiv_symm_apply_val
@[simps! unit_app_val counit_app_val]
def adjunction [HasSheafCompose J F] (adj : G ⊣ F) :
composeAndSheafify J G ⊣ sheafCompose J F :=
Adjunction.mkOfHomEquiv
{ homEquiv := composeEquiv J adj
homEquiv_naturality_left_symm := fun f g => by
ext1
dsimp [composeEquiv]
rw [sheafifyMap_sheafifyLift]
erw [Adjunction.homEquiv_naturality_left_symm]
rw [whiskeringRight_obj_map]
rfl
homEquiv_naturality_right := fun f g => by
ext
dsimp [composeEquiv]
erw [Adjunction.homEquiv_unit, Adjunction.homEquiv_unit]
dsimp
simp }
set_option linter.uppercaseLean3 false in
#align category_theory.Sheaf.adjunction CategoryTheory.Sheaf.adjunction
instance [F.IsRightAdjoint] : (sheafCompose J F).IsRightAdjoint :=
(adjunction J (Adjunction.ofIsRightAdjoint F)).isRightAdjoint
instance [G.IsLeftAdjoint] : (composeAndSheafify J G).IsLeftAdjoint :=
(adjunction J (Adjunction.ofIsLeftAdjoint G)).isLeftAdjoint
lemma preservesSheafification_of_adjunction (adj : G ⊣ F) :
J.PreservesSheafification G where
le P Q f hf := by
have := adj.isRightAdjoint
rw [MorphismProperty.inverseImage_iff]
dsimp
intro R hR
rw [← ((adj.whiskerRight Cᵒᵖ).homEquiv P R).comp_bijective]
convert (((adj.whiskerRight Cᵒᵖ).homEquiv Q R).trans
(hf.homEquiv (R ⋙ F) ((sheafCompose J F).obj ⟨R, hR⟩).cond)).bijective
ext g X
dsimp [Adjunction.whiskerRight, Adjunction.mkOfUnitCounit]
simp
instance [G.IsLeftAdjoint] : J.PreservesSheafification G :=
preservesSheafification_of_adjunction J (Adjunction.ofIsLeftAdjoint G)
section ForgetToType
variable [ConcreteCategory D] [HasSheafCompose J (forget D)]
abbrev composeAndSheafifyFromTypes (G : Type max v u ⥤ D) : SheafOfTypes J ⥤ Sheaf J D :=
(sheafEquivSheafOfTypes J).inverse ⋙ composeAndSheafify _ G
set_option linter.uppercaseLean3 false in
#align category_theory.Sheaf.compose_and_sheafify_from_types CategoryTheory.Sheaf.composeAndSheafifyFromTypes
def adjunctionToTypes {G : Type max v u ⥤ D} (adj : G ⊣ forget D) :
composeAndSheafifyFromTypes J G ⊣ sheafForget J :=
(sheafEquivSheafOfTypes J).symm.toAdjunction.comp (adjunction J adj)
set_option linter.uppercaseLean3 false in
#align category_theory.Sheaf.adjunction_to_types CategoryTheory.Sheaf.adjunctionToTypes
@[simp]
| Mathlib/CategoryTheory/Sites/Adjunction.lean | 136 | 143 | theorem adjunctionToTypes_unit_app_val {G : Type max v u ⥤ D} (adj : G ⊣ forget D)
(Y : SheafOfTypes J) :
((adjunctionToTypes J adj).unit.app Y).val =
(adj.whiskerRight _).unit.app ((sheafOfTypesToPresheaf J).obj Y) ≫
whiskerRight (toSheafify J _) (forget D) := by |
dsimp [adjunctionToTypes, Adjunction.comp]
simp
rfl
|
import Mathlib.Order.Antichain
import Mathlib.Order.UpperLower.Basic
import Mathlib.Order.Interval.Set.Basic
import Mathlib.Order.RelIso.Set
#align_import order.minimal from "leanprover-community/mathlib"@"59694bd07f0a39c5beccba34bd9f413a160782bf"
open Function Set
variable {α : Type*} (r r₁ r₂ : α → α → Prop) (s t : Set α) (a b : α)
def maximals : Set α :=
{ a ∈ s | ∀ ⦃b⦄, b ∈ s → r a b → r b a }
#align maximals maximals
def minimals : Set α :=
{ a ∈ s | ∀ ⦃b⦄, b ∈ s → r b a → r a b }
#align minimals minimals
theorem maximals_subset : maximals r s ⊆ s :=
sep_subset _ _
#align maximals_subset maximals_subset
theorem minimals_subset : minimals r s ⊆ s :=
sep_subset _ _
#align minimals_subset minimals_subset
@[simp]
theorem maximals_empty : maximals r ∅ = ∅ :=
sep_empty _
#align maximals_empty maximals_empty
@[simp]
theorem minimals_empty : minimals r ∅ = ∅ :=
sep_empty _
#align minimals_empty minimals_empty
@[simp]
theorem maximals_singleton : maximals r {a} = {a} :=
(maximals_subset _ _).antisymm <|
singleton_subset_iff.2 <|
⟨rfl, by
rintro b (rfl : b = a)
exact id⟩
#align maximals_singleton maximals_singleton
@[simp]
theorem minimals_singleton : minimals r {a} = {a} :=
maximals_singleton _ _
#align minimals_singleton minimals_singleton
theorem maximals_swap : maximals (swap r) s = minimals r s :=
rfl
#align maximals_swap maximals_swap
theorem minimals_swap : minimals (swap r) s = maximals r s :=
rfl
#align minimals_swap minimals_swap
set_option autoImplicit true
theorem mem_minimals_iff_forall_ssubset_not_mem (s : Set (Set α)) :
x ∈ minimals (· ⊆ ·) s ↔ x ∈ s ∧ ∀ ⦃y⦄, y ⊂ x → y ∉ s :=
mem_minimals_iff_forall_lt_not_mem' (· ⊂ ·)
theorem mem_minimals_iff_forall_lt_not_mem [PartialOrder α] {s : Set α} :
x ∈ minimals (· ≤ ·) s ↔ x ∈ s ∧ ∀ ⦃y⦄, y < x → y ∉ s :=
mem_minimals_iff_forall_lt_not_mem' (· < ·)
theorem mem_maximals_iff_forall_ssubset_not_mem {s : Set (Set α)} :
x ∈ maximals (· ⊆ ·) s ↔ x ∈ s ∧ ∀ ⦃y⦄, x ⊂ y → y ∉ s :=
mem_maximals_iff_forall_lt_not_mem' (· ⊂ ·)
theorem mem_maximals_iff_forall_lt_not_mem [PartialOrder α] {s : Set α} :
x ∈ maximals (· ≤ ·) s ↔ x ∈ s ∧ ∀ ⦃y⦄, x < y → y ∉ s :=
mem_maximals_iff_forall_lt_not_mem' (· < ·)
-- Porting note (#10756): new theorem
theorem maximals_of_symm [IsSymm α r] : maximals r s = s :=
sep_eq_self_iff_mem_true.2 fun _ _ _ _ => symm
-- Porting note (#10756): new theorem
theorem minimals_of_symm [IsSymm α r] : minimals r s = s :=
sep_eq_self_iff_mem_true.2 fun _ _ _ _ => symm
theorem maximals_eq_minimals [IsSymm α r] : maximals r s = minimals r s := by
rw [minimals_of_symm, maximals_of_symm]
#align maximals_eq_minimals maximals_eq_minimals
variable {r r₁ r₂ s t a}
-- Porting note (#11215): TODO: use `h.induction_on`
theorem Set.Subsingleton.maximals_eq (h : s.Subsingleton) : maximals r s = s := by
rcases h.eq_empty_or_singleton with (rfl | ⟨x, rfl⟩)
exacts [minimals_empty _, maximals_singleton _ _]
#align set.subsingleton.maximals_eq Set.Subsingleton.maximals_eq
theorem Set.Subsingleton.minimals_eq (h : s.Subsingleton) : minimals r s = s :=
h.maximals_eq
#align set.subsingleton.minimals_eq Set.Subsingleton.minimals_eq
theorem maximals_mono [IsAntisymm α r₂] (h : ∀ a b, r₁ a b → r₂ a b) :
maximals r₂ s ⊆ maximals r₁ s := fun a ha =>
⟨ha.1, fun b hb hab => by
have := eq_of_mem_maximals ha hb (h _ _ hab)
subst this
exact hab⟩
#align maximals_mono maximals_mono
theorem minimals_mono [IsAntisymm α r₂] (h : ∀ a b, r₁ a b → r₂ a b) :
minimals r₂ s ⊆ minimals r₁ s := fun a ha =>
⟨ha.1, fun b hb hab => by
have := eq_of_mem_minimals ha hb (h _ _ hab)
subst this
exact hab⟩
#align minimals_mono minimals_mono
| Mathlib/Order/Minimal.lean | 205 | 209 | theorem maximals_union : maximals r (s ∪ t) ⊆ maximals r s ∪ maximals r t := by |
intro a ha
obtain h | h := ha.1
· exact Or.inl ⟨h, fun b hb => ha.2 <| Or.inl hb⟩
· exact Or.inr ⟨h, fun b hb => ha.2 <| Or.inr hb⟩
|
import Mathlib.Analysis.Calculus.TangentCone
import Mathlib.Analysis.NormedSpace.OperatorNorm.Asymptotics
#align_import analysis.calculus.fderiv.basic from "leanprover-community/mathlib"@"41bef4ae1254365bc190aee63b947674d2977f01"
open Filter Asymptotics ContinuousLinearMap Set Metric
open scoped Classical
open Topology NNReal Filter Asymptotics ENNReal
noncomputable section
section
variable {𝕜 : Type*} [NontriviallyNormedField 𝕜]
variable {E : Type*} [NormedAddCommGroup E] [NormedSpace 𝕜 E]
variable {F : Type*} [NormedAddCommGroup F] [NormedSpace 𝕜 F]
variable {G : Type*} [NormedAddCommGroup G] [NormedSpace 𝕜 G]
variable {G' : Type*} [NormedAddCommGroup G'] [NormedSpace 𝕜 G']
@[mk_iff hasFDerivAtFilter_iff_isLittleO]
structure HasFDerivAtFilter (f : E → F) (f' : E →L[𝕜] F) (x : E) (L : Filter E) : Prop where
of_isLittleO :: isLittleO : (fun x' => f x' - f x - f' (x' - x)) =o[L] fun x' => x' - x
#align has_fderiv_at_filter HasFDerivAtFilter
@[fun_prop]
def HasFDerivWithinAt (f : E → F) (f' : E →L[𝕜] F) (s : Set E) (x : E) :=
HasFDerivAtFilter f f' x (𝓝[s] x)
#align has_fderiv_within_at HasFDerivWithinAt
@[fun_prop]
def HasFDerivAt (f : E → F) (f' : E →L[𝕜] F) (x : E) :=
HasFDerivAtFilter f f' x (𝓝 x)
#align has_fderiv_at HasFDerivAt
@[fun_prop]
def HasStrictFDerivAt (f : E → F) (f' : E →L[𝕜] F) (x : E) :=
(fun p : E × E => f p.1 - f p.2 - f' (p.1 - p.2)) =o[𝓝 (x, x)] fun p : E × E => p.1 - p.2
#align has_strict_fderiv_at HasStrictFDerivAt
variable (𝕜)
@[fun_prop]
def DifferentiableWithinAt (f : E → F) (s : Set E) (x : E) :=
∃ f' : E →L[𝕜] F, HasFDerivWithinAt f f' s x
#align differentiable_within_at DifferentiableWithinAt
@[fun_prop]
def DifferentiableAt (f : E → F) (x : E) :=
∃ f' : E →L[𝕜] F, HasFDerivAt f f' x
#align differentiable_at DifferentiableAt
irreducible_def fderivWithin (f : E → F) (s : Set E) (x : E) : E →L[𝕜] F :=
if 𝓝[s \ {x}] x = ⊥ then 0 else
if h : ∃ f', HasFDerivWithinAt f f' s x then Classical.choose h else 0
#align fderiv_within fderivWithin
irreducible_def fderiv (f : E → F) (x : E) : E →L[𝕜] F :=
if h : ∃ f', HasFDerivAt f f' x then Classical.choose h else 0
#align fderiv fderiv
@[fun_prop]
def DifferentiableOn (f : E → F) (s : Set E) :=
∀ x ∈ s, DifferentiableWithinAt 𝕜 f s x
#align differentiable_on DifferentiableOn
@[fun_prop]
def Differentiable (f : E → F) :=
∀ x, DifferentiableAt 𝕜 f x
#align differentiable Differentiable
variable {𝕜}
variable {f f₀ f₁ g : E → F}
variable {f' f₀' f₁' g' : E →L[𝕜] F}
variable (e : E →L[𝕜] F)
variable {x : E}
variable {s t : Set E}
variable {L L₁ L₂ : Filter E}
theorem fderivWithin_zero_of_isolated (h : 𝓝[s \ {x}] x = ⊥) : fderivWithin 𝕜 f s x = 0 := by
rw [fderivWithin, if_pos h]
theorem fderivWithin_zero_of_nmem_closure (h : x ∉ closure s) : fderivWithin 𝕜 f s x = 0 := by
apply fderivWithin_zero_of_isolated
simp only [mem_closure_iff_nhdsWithin_neBot, neBot_iff, Ne, Classical.not_not] at h
rw [eq_bot_iff, ← h]
exact nhdsWithin_mono _ diff_subset
theorem fderivWithin_zero_of_not_differentiableWithinAt (h : ¬DifferentiableWithinAt 𝕜 f s x) :
fderivWithin 𝕜 f s x = 0 := by
have : ¬∃ f', HasFDerivWithinAt f f' s x := h
simp [fderivWithin, this]
#align fderiv_within_zero_of_not_differentiable_within_at fderivWithin_zero_of_not_differentiableWithinAt
theorem fderiv_zero_of_not_differentiableAt (h : ¬DifferentiableAt 𝕜 f x) : fderiv 𝕜 f x = 0 := by
have : ¬∃ f', HasFDerivAt f f' x := h
simp [fderiv, this]
#align fderiv_zero_of_not_differentiable_at fderiv_zero_of_not_differentiableAt
section Const
@[fun_prop]
theorem hasStrictFDerivAt_const (c : F) (x : E) :
HasStrictFDerivAt (fun _ => c) (0 : E →L[𝕜] F) x :=
(isLittleO_zero _ _).congr_left fun _ => by simp only [zero_apply, sub_self]
#align has_strict_fderiv_at_const hasStrictFDerivAt_const
theorem hasFDerivAtFilter_const (c : F) (x : E) (L : Filter E) :
HasFDerivAtFilter (fun _ => c) (0 : E →L[𝕜] F) x L :=
.of_isLittleO <| (isLittleO_zero _ _).congr_left fun _ => by simp only [zero_apply, sub_self]
#align has_fderiv_at_filter_const hasFDerivAtFilter_const
@[fun_prop]
theorem hasFDerivWithinAt_const (c : F) (x : E) (s : Set E) :
HasFDerivWithinAt (fun _ => c) (0 : E →L[𝕜] F) s x :=
hasFDerivAtFilter_const _ _ _
#align has_fderiv_within_at_const hasFDerivWithinAt_const
@[fun_prop]
theorem hasFDerivAt_const (c : F) (x : E) : HasFDerivAt (fun _ => c) (0 : E →L[𝕜] F) x :=
hasFDerivAtFilter_const _ _ _
#align has_fderiv_at_const hasFDerivAt_const
@[simp, fun_prop]
theorem differentiableAt_const (c : F) : DifferentiableAt 𝕜 (fun _ => c) x :=
⟨0, hasFDerivAt_const c x⟩
#align differentiable_at_const differentiableAt_const
@[fun_prop]
theorem differentiableWithinAt_const (c : F) : DifferentiableWithinAt 𝕜 (fun _ => c) s x :=
DifferentiableAt.differentiableWithinAt (differentiableAt_const _)
#align differentiable_within_at_const differentiableWithinAt_const
theorem fderiv_const_apply (c : F) : fderiv 𝕜 (fun _ => c) x = 0 :=
HasFDerivAt.fderiv (hasFDerivAt_const c x)
#align fderiv_const_apply fderiv_const_apply
@[simp]
| Mathlib/Analysis/Calculus/FDeriv/Basic.lean | 1,186 | 1,189 | theorem fderiv_const (c : F) : (fderiv 𝕜 fun _ : E => c) = 0 := by |
ext m
rw [fderiv_const_apply]
rfl
|
import Mathlib.Tactic.TFAE
import Mathlib.Topology.ContinuousOn
#align_import topology.inseparable from "leanprover-community/mathlib"@"bcfa726826abd57587355b4b5b7e78ad6527b7e4"
open Set Filter Function Topology List
variable {X Y Z α ι : Type*} {π : ι → Type*} [TopologicalSpace X] [TopologicalSpace Y]
[TopologicalSpace Z] [∀ i, TopologicalSpace (π i)] {x y z : X} {s : Set X} {f g : X → Y}
theorem specializes_TFAE (x y : X) :
TFAE [x ⤳ y,
pure x ≤ 𝓝 y,
∀ s : Set X , IsOpen s → y ∈ s → x ∈ s,
∀ s : Set X , IsClosed s → x ∈ s → y ∈ s,
y ∈ closure ({ x } : Set X),
closure ({ y } : Set X) ⊆ closure { x },
ClusterPt y (pure x)] := by
tfae_have 1 → 2
· exact (pure_le_nhds _).trans
tfae_have 2 → 3
· exact fun h s hso hy => h (hso.mem_nhds hy)
tfae_have 3 → 4
· exact fun h s hsc hx => of_not_not fun hy => h sᶜ hsc.isOpen_compl hy hx
tfae_have 4 → 5
· exact fun h => h _ isClosed_closure (subset_closure <| mem_singleton _)
tfae_have 6 ↔ 5
· exact isClosed_closure.closure_subset_iff.trans singleton_subset_iff
tfae_have 5 ↔ 7
· rw [mem_closure_iff_clusterPt, principal_singleton]
tfae_have 5 → 1
· refine fun h => (nhds_basis_opens _).ge_iff.2 ?_
rintro s ⟨hy, ho⟩
rcases mem_closure_iff.1 h s ho hy with ⟨z, hxs, rfl : z = x⟩
exact ho.mem_nhds hxs
tfae_finish
#align specializes_tfae specializes_TFAE
theorem specializes_iff_nhds : x ⤳ y ↔ 𝓝 x ≤ 𝓝 y :=
Iff.rfl
#align specializes_iff_nhds specializes_iff_nhds
theorem Specializes.not_disjoint (h : x ⤳ y) : ¬Disjoint (𝓝 x) (𝓝 y) := fun hd ↦
absurd (hd.mono_right h) <| by simp [NeBot.ne']
theorem specializes_iff_pure : x ⤳ y ↔ pure x ≤ 𝓝 y :=
(specializes_TFAE x y).out 0 1
#align specializes_iff_pure specializes_iff_pure
alias ⟨Specializes.nhds_le_nhds, _⟩ := specializes_iff_nhds
#align specializes.nhds_le_nhds Specializes.nhds_le_nhds
alias ⟨Specializes.pure_le_nhds, _⟩ := specializes_iff_pure
#align specializes.pure_le_nhds Specializes.pure_le_nhds
theorem ker_nhds_eq_specializes : (𝓝 x).ker = {y | y ⤳ x} := by
ext; simp [specializes_iff_pure, le_def]
theorem specializes_iff_forall_open : x ⤳ y ↔ ∀ s : Set X, IsOpen s → y ∈ s → x ∈ s :=
(specializes_TFAE x y).out 0 2
#align specializes_iff_forall_open specializes_iff_forall_open
theorem Specializes.mem_open (h : x ⤳ y) (hs : IsOpen s) (hy : y ∈ s) : x ∈ s :=
specializes_iff_forall_open.1 h s hs hy
#align specializes.mem_open Specializes.mem_open
theorem IsOpen.not_specializes (hs : IsOpen s) (hx : x ∉ s) (hy : y ∈ s) : ¬x ⤳ y := fun h =>
hx <| h.mem_open hs hy
#align is_open.not_specializes IsOpen.not_specializes
theorem specializes_iff_forall_closed : x ⤳ y ↔ ∀ s : Set X, IsClosed s → x ∈ s → y ∈ s :=
(specializes_TFAE x y).out 0 3
#align specializes_iff_forall_closed specializes_iff_forall_closed
theorem Specializes.mem_closed (h : x ⤳ y) (hs : IsClosed s) (hx : x ∈ s) : y ∈ s :=
specializes_iff_forall_closed.1 h s hs hx
#align specializes.mem_closed Specializes.mem_closed
theorem IsClosed.not_specializes (hs : IsClosed s) (hx : x ∈ s) (hy : y ∉ s) : ¬x ⤳ y := fun h =>
hy <| h.mem_closed hs hx
#align is_closed.not_specializes IsClosed.not_specializes
theorem specializes_iff_mem_closure : x ⤳ y ↔ y ∈ closure ({x} : Set X) :=
(specializes_TFAE x y).out 0 4
#align specializes_iff_mem_closure specializes_iff_mem_closure
alias ⟨Specializes.mem_closure, _⟩ := specializes_iff_mem_closure
#align specializes.mem_closure Specializes.mem_closure
theorem specializes_iff_closure_subset : x ⤳ y ↔ closure ({y} : Set X) ⊆ closure {x} :=
(specializes_TFAE x y).out 0 5
#align specializes_iff_closure_subset specializes_iff_closure_subset
alias ⟨Specializes.closure_subset, _⟩ := specializes_iff_closure_subset
#align specializes.closure_subset Specializes.closure_subset
-- Porting note (#10756): new lemma
theorem specializes_iff_clusterPt : x ⤳ y ↔ ClusterPt y (pure x) :=
(specializes_TFAE x y).out 0 6
theorem Filter.HasBasis.specializes_iff {ι} {p : ι → Prop} {s : ι → Set X}
(h : (𝓝 y).HasBasis p s) : x ⤳ y ↔ ∀ i, p i → x ∈ s i :=
specializes_iff_pure.trans h.ge_iff
#align filter.has_basis.specializes_iff Filter.HasBasis.specializes_iff
theorem specializes_rfl : x ⤳ x := le_rfl
#align specializes_rfl specializes_rfl
@[refl]
theorem specializes_refl (x : X) : x ⤳ x :=
specializes_rfl
#align specializes_refl specializes_refl
@[trans]
theorem Specializes.trans : x ⤳ y → y ⤳ z → x ⤳ z :=
le_trans
#align specializes.trans Specializes.trans
theorem specializes_of_eq (e : x = y) : x ⤳ y :=
e ▸ specializes_refl x
#align specializes_of_eq specializes_of_eq
theorem specializes_of_nhdsWithin (h₁ : 𝓝[s] x ≤ 𝓝[s] y) (h₂ : x ∈ s) : x ⤳ y :=
specializes_iff_pure.2 <|
calc
pure x ≤ 𝓝[s] x := le_inf (pure_le_nhds _) (le_principal_iff.2 h₂)
_ ≤ 𝓝[s] y := h₁
_ ≤ 𝓝 y := inf_le_left
#align specializes_of_nhds_within specializes_of_nhdsWithin
theorem Specializes.map_of_continuousAt (h : x ⤳ y) (hy : ContinuousAt f y) : f x ⤳ f y :=
specializes_iff_pure.2 fun _s hs =>
mem_pure.2 <| mem_preimage.1 <| mem_of_mem_nhds <| hy.mono_left h hs
#align specializes.map_of_continuous_at Specializes.map_of_continuousAt
theorem Specializes.map (h : x ⤳ y) (hf : Continuous f) : f x ⤳ f y :=
h.map_of_continuousAt hf.continuousAt
#align specializes.map Specializes.map
theorem Inducing.specializes_iff (hf : Inducing f) : f x ⤳ f y ↔ x ⤳ y := by
simp only [specializes_iff_mem_closure, hf.closure_eq_preimage_closure_image, image_singleton,
mem_preimage]
#align inducing.specializes_iff Inducing.specializes_iff
theorem subtype_specializes_iff {p : X → Prop} (x y : Subtype p) : x ⤳ y ↔ (x : X) ⤳ y :=
inducing_subtype_val.specializes_iff.symm
#align subtype_specializes_iff subtype_specializes_iff
@[simp]
theorem specializes_prod {x₁ x₂ : X} {y₁ y₂ : Y} : (x₁, y₁) ⤳ (x₂, y₂) ↔ x₁ ⤳ x₂ ∧ y₁ ⤳ y₂ := by
simp only [Specializes, nhds_prod_eq, prod_le_prod]
#align specializes_prod specializes_prod
theorem Specializes.prod {x₁ x₂ : X} {y₁ y₂ : Y} (hx : x₁ ⤳ x₂) (hy : y₁ ⤳ y₂) :
(x₁, y₁) ⤳ (x₂, y₂) :=
specializes_prod.2 ⟨hx, hy⟩
#align specializes.prod Specializes.prod
theorem Specializes.fst {a b : X × Y} (h : a ⤳ b) : a.1 ⤳ b.1 := (specializes_prod.1 h).1
theorem Specializes.snd {a b : X × Y} (h : a ⤳ b) : a.2 ⤳ b.2 := (specializes_prod.1 h).2
@[simp]
theorem specializes_pi {f g : ∀ i, π i} : f ⤳ g ↔ ∀ i, f i ⤳ g i := by
simp only [Specializes, nhds_pi, pi_le_pi]
#align specializes_pi specializes_pi
theorem not_specializes_iff_exists_open : ¬x ⤳ y ↔ ∃ S : Set X, IsOpen S ∧ y ∈ S ∧ x ∉ S := by
rw [specializes_iff_forall_open]
push_neg
rfl
#align not_specializes_iff_exists_open not_specializes_iff_exists_open
theorem not_specializes_iff_exists_closed : ¬x ⤳ y ↔ ∃ S : Set X, IsClosed S ∧ x ∈ S ∧ y ∉ S := by
rw [specializes_iff_forall_closed]
push_neg
rfl
#align not_specializes_iff_exists_closed not_specializes_iff_exists_closed
theorem IsOpen.continuous_piecewise_of_specializes [DecidablePred (· ∈ s)] (hs : IsOpen s)
(hf : Continuous f) (hg : Continuous g) (hspec : ∀ x, f x ⤳ g x) :
Continuous (s.piecewise f g) := by
have : ∀ U, IsOpen U → g ⁻¹' U ⊆ f ⁻¹' U := fun U hU x hx ↦ (hspec x).mem_open hU hx
rw [continuous_def]
intro U hU
rw [piecewise_preimage, ite_eq_of_subset_right _ (this U hU)]
exact hU.preimage hf |>.inter hs |>.union (hU.preimage hg)
theorem IsClosed.continuous_piecewise_of_specializes [DecidablePred (· ∈ s)] (hs : IsClosed s)
(hf : Continuous f) (hg : Continuous g) (hspec : ∀ x, g x ⤳ f x) :
Continuous (s.piecewise f g) := by
simpa only [piecewise_compl] using hs.isOpen_compl.continuous_piecewise_of_specializes hg hf hspec
theorem Continuous.specialization_monotone (hf : Continuous f) :
@Monotone _ _ (specializationPreorder X) (specializationPreorder Y) f := fun _ _ h => h.map hf
#align continuous.specialization_monotone Continuous.specialization_monotone
local infixl:0 " ~ᵢ " => Inseparable
theorem inseparable_def : (x ~ᵢ y) ↔ 𝓝 x = 𝓝 y :=
Iff.rfl
#align inseparable_def inseparable_def
theorem inseparable_iff_specializes_and : (x ~ᵢ y) ↔ x ⤳ y ∧ y ⤳ x :=
le_antisymm_iff
#align inseparable_iff_specializes_and inseparable_iff_specializes_and
theorem Inseparable.specializes (h : x ~ᵢ y) : x ⤳ y := h.le
#align inseparable.specializes Inseparable.specializes
theorem Inseparable.specializes' (h : x ~ᵢ y) : y ⤳ x := h.ge
#align inseparable.specializes' Inseparable.specializes'
theorem Specializes.antisymm (h₁ : x ⤳ y) (h₂ : y ⤳ x) : x ~ᵢ y :=
le_antisymm h₁ h₂
#align specializes.antisymm Specializes.antisymm
theorem inseparable_iff_forall_open : (x ~ᵢ y) ↔ ∀ s : Set X, IsOpen s → (x ∈ s ↔ y ∈ s) := by
simp only [inseparable_iff_specializes_and, specializes_iff_forall_open, ← forall_and, ← iff_def,
Iff.comm]
#align inseparable_iff_forall_open inseparable_iff_forall_open
theorem not_inseparable_iff_exists_open :
¬(x ~ᵢ y) ↔ ∃ s : Set X, IsOpen s ∧ Xor' (x ∈ s) (y ∈ s) := by
simp [inseparable_iff_forall_open, ← xor_iff_not_iff]
#align not_inseparable_iff_exists_open not_inseparable_iff_exists_open
theorem inseparable_iff_forall_closed : (x ~ᵢ y) ↔ ∀ s : Set X, IsClosed s → (x ∈ s ↔ y ∈ s) := by
simp only [inseparable_iff_specializes_and, specializes_iff_forall_closed, ← forall_and, ←
iff_def]
#align inseparable_iff_forall_closed inseparable_iff_forall_closed
theorem inseparable_iff_mem_closure :
(x ~ᵢ y) ↔ x ∈ closure ({y} : Set X) ∧ y ∈ closure ({x} : Set X) :=
inseparable_iff_specializes_and.trans <| by simp only [specializes_iff_mem_closure, and_comm]
#align inseparable_iff_mem_closure inseparable_iff_mem_closure
theorem inseparable_iff_closure_eq : (x ~ᵢ y) ↔ closure ({x} : Set X) = closure {y} := by
simp only [inseparable_iff_specializes_and, specializes_iff_closure_subset, ← subset_antisymm_iff,
eq_comm]
#align inseparable_iff_closure_eq inseparable_iff_closure_eq
theorem inseparable_of_nhdsWithin_eq (hx : x ∈ s) (hy : y ∈ s) (h : 𝓝[s] x = 𝓝[s] y) : x ~ᵢ y :=
(specializes_of_nhdsWithin h.le hx).antisymm (specializes_of_nhdsWithin h.ge hy)
#align inseparable_of_nhds_within_eq inseparable_of_nhdsWithin_eq
theorem Inducing.inseparable_iff (hf : Inducing f) : (f x ~ᵢ f y) ↔ (x ~ᵢ y) := by
simp only [inseparable_iff_specializes_and, hf.specializes_iff]
#align inducing.inseparable_iff Inducing.inseparable_iff
theorem subtype_inseparable_iff {p : X → Prop} (x y : Subtype p) : (x ~ᵢ y) ↔ ((x : X) ~ᵢ y) :=
inducing_subtype_val.inseparable_iff.symm
#align subtype_inseparable_iff subtype_inseparable_iff
@[simp] theorem inseparable_prod {x₁ x₂ : X} {y₁ y₂ : Y} :
((x₁, y₁) ~ᵢ (x₂, y₂)) ↔ (x₁ ~ᵢ x₂) ∧ (y₁ ~ᵢ y₂) := by
simp only [Inseparable, nhds_prod_eq, prod_inj]
#align inseparable_prod inseparable_prod
theorem Inseparable.prod {x₁ x₂ : X} {y₁ y₂ : Y} (hx : x₁ ~ᵢ x₂) (hy : y₁ ~ᵢ y₂) :
(x₁, y₁) ~ᵢ (x₂, y₂) :=
inseparable_prod.2 ⟨hx, hy⟩
#align inseparable.prod Inseparable.prod
@[simp]
theorem inseparable_pi {f g : ∀ i, π i} : (f ~ᵢ g) ↔ ∀ i, f i ~ᵢ g i := by
simp only [Inseparable, nhds_pi, funext_iff, pi_inj]
#align inseparable_pi inseparable_pi
theorem IsClosed.not_inseparable (hs : IsClosed s) (hx : x ∈ s) (hy : y ∉ s) : ¬(x ~ᵢ y) := fun h =>
hy <| (h.mem_closed_iff hs).1 hx
#align is_closed.not_inseparable IsClosed.not_inseparable
theorem IsOpen.not_inseparable (hs : IsOpen s) (hx : x ∈ s) (hy : y ∉ s) : ¬(x ~ᵢ y) := fun h =>
hy <| (h.mem_open_iff hs).1 hx
#align is_open.not_inseparable IsOpen.not_inseparable
variable (X)
instance : TopologicalSpace (SeparationQuotient X) := instTopologicalSpaceQuotient
variable {X}
variable {t : Set (SeparationQuotient X)}
namespace SeparationQuotient
def mk : X → SeparationQuotient X := Quotient.mk''
#align separation_quotient.mk SeparationQuotient.mk
theorem quotientMap_mk : QuotientMap (mk : X → SeparationQuotient X) :=
quotientMap_quot_mk
#align separation_quotient.quotient_map_mk SeparationQuotient.quotientMap_mk
theorem continuous_mk : Continuous (mk : X → SeparationQuotient X) :=
continuous_quot_mk
#align separation_quotient.continuous_mk SeparationQuotient.continuous_mk
@[simp]
theorem mk_eq_mk : mk x = mk y ↔ (x ~ᵢ y) :=
Quotient.eq''
#align separation_quotient.mk_eq_mk SeparationQuotient.mk_eq_mk
theorem surjective_mk : Surjective (mk : X → SeparationQuotient X) :=
surjective_quot_mk _
#align separation_quotient.surjective_mk SeparationQuotient.surjective_mk
@[simp]
theorem range_mk : range (mk : X → SeparationQuotient X) = univ :=
surjective_mk.range_eq
#align separation_quotient.range_mk SeparationQuotient.range_mk
instance [Nonempty X] : Nonempty (SeparationQuotient X) :=
Nonempty.map mk ‹_›
instance [Inhabited X] : Inhabited (SeparationQuotient X) :=
⟨mk default⟩
instance [Subsingleton X] : Subsingleton (SeparationQuotient X) :=
surjective_mk.subsingleton
theorem preimage_image_mk_open (hs : IsOpen s) : mk ⁻¹' (mk '' s) = s := by
refine Subset.antisymm ?_ (subset_preimage_image _ _)
rintro x ⟨y, hys, hxy⟩
exact ((mk_eq_mk.1 hxy).mem_open_iff hs).1 hys
#align separation_quotient.preimage_image_mk_open SeparationQuotient.preimage_image_mk_open
theorem isOpenMap_mk : IsOpenMap (mk : X → SeparationQuotient X) := fun s hs =>
quotientMap_mk.isOpen_preimage.1 <| by rwa [preimage_image_mk_open hs]
#align separation_quotient.is_open_map_mk SeparationQuotient.isOpenMap_mk
theorem preimage_image_mk_closed (hs : IsClosed s) : mk ⁻¹' (mk '' s) = s := by
refine Subset.antisymm ?_ (subset_preimage_image _ _)
rintro x ⟨y, hys, hxy⟩
exact ((mk_eq_mk.1 hxy).mem_closed_iff hs).1 hys
#align separation_quotient.preimage_image_mk_closed SeparationQuotient.preimage_image_mk_closed
theorem inducing_mk : Inducing (mk : X → SeparationQuotient X) :=
⟨le_antisymm (continuous_iff_le_induced.1 continuous_mk) fun s hs =>
⟨mk '' s, isOpenMap_mk s hs, preimage_image_mk_open hs⟩⟩
#align separation_quotient.inducing_mk SeparationQuotient.inducing_mk
theorem isClosedMap_mk : IsClosedMap (mk : X → SeparationQuotient X) :=
inducing_mk.isClosedMap <| by rw [range_mk]; exact isClosed_univ
#align separation_quotient.is_closed_map_mk SeparationQuotient.isClosedMap_mk
@[simp]
theorem comap_mk_nhds_mk : comap mk (𝓝 (mk x)) = 𝓝 x :=
(inducing_mk.nhds_eq_comap _).symm
#align separation_quotient.comap_mk_nhds_mk SeparationQuotient.comap_mk_nhds_mk
@[simp]
theorem comap_mk_nhdsSet_image : comap mk (𝓝ˢ (mk '' s)) = 𝓝ˢ s :=
(inducing_mk.nhdsSet_eq_comap _).symm
#align separation_quotient.comap_mk_nhds_set_image SeparationQuotient.comap_mk_nhdsSet_image
theorem map_mk_nhds : map mk (𝓝 x) = 𝓝 (mk x) := by
rw [← comap_mk_nhds_mk, map_comap_of_surjective surjective_mk]
#align separation_quotient.map_mk_nhds SeparationQuotient.map_mk_nhds
theorem map_mk_nhdsSet : map mk (𝓝ˢ s) = 𝓝ˢ (mk '' s) := by
rw [← comap_mk_nhdsSet_image, map_comap_of_surjective surjective_mk]
#align separation_quotient.map_mk_nhds_set SeparationQuotient.map_mk_nhdsSet
theorem comap_mk_nhdsSet : comap mk (𝓝ˢ t) = 𝓝ˢ (mk ⁻¹' t) := by
conv_lhs => rw [← image_preimage_eq t surjective_mk, comap_mk_nhdsSet_image]
#align separation_quotient.comap_mk_nhds_set SeparationQuotient.comap_mk_nhdsSet
theorem preimage_mk_closure : mk ⁻¹' closure t = closure (mk ⁻¹' t) :=
isOpenMap_mk.preimage_closure_eq_closure_preimage continuous_mk t
#align separation_quotient.preimage_mk_closure SeparationQuotient.preimage_mk_closure
theorem preimage_mk_interior : mk ⁻¹' interior t = interior (mk ⁻¹' t) :=
isOpenMap_mk.preimage_interior_eq_interior_preimage continuous_mk t
#align separation_quotient.preimage_mk_interior SeparationQuotient.preimage_mk_interior
theorem preimage_mk_frontier : mk ⁻¹' frontier t = frontier (mk ⁻¹' t) :=
isOpenMap_mk.preimage_frontier_eq_frontier_preimage continuous_mk t
#align separation_quotient.preimage_mk_frontier SeparationQuotient.preimage_mk_frontier
theorem image_mk_closure : mk '' closure s = closure (mk '' s) :=
(image_closure_subset_closure_image continuous_mk).antisymm <|
isClosedMap_mk.closure_image_subset _
#align separation_quotient.image_mk_closure SeparationQuotient.image_mk_closure
theorem map_prod_map_mk_nhds (x : X) (y : Y) :
map (Prod.map mk mk) (𝓝 (x, y)) = 𝓝 (mk x, mk y) := by
rw [nhds_prod_eq, ← prod_map_map_eq', map_mk_nhds, map_mk_nhds, nhds_prod_eq]
#align separation_quotient.map_prod_map_mk_nhds SeparationQuotient.map_prod_map_mk_nhds
theorem map_mk_nhdsWithin_preimage (s : Set (SeparationQuotient X)) (x : X) :
map mk (𝓝[mk ⁻¹' s] x) = 𝓝[s] mk x := by
rw [nhdsWithin, ← comap_principal, Filter.push_pull, nhdsWithin, map_mk_nhds]
#align separation_quotient.map_mk_nhds_within_preimage SeparationQuotient.map_mk_nhdsWithin_preimage
theorem quotientMap_prodMap_mk : QuotientMap (Prod.map mk mk : X × Y → _) := by
have hsurj : Surjective (Prod.map mk mk : X × Y → _) := surjective_mk.prodMap surjective_mk
refine quotientMap_iff.2 ⟨hsurj, fun s ↦ ?_⟩
refine ⟨fun hs ↦ hs.preimage (continuous_mk.prod_map continuous_mk), fun hs ↦ ?_⟩
refine isOpen_iff_mem_nhds.2 <| hsurj.forall.2 fun (x, y) h ↦ ?_
rw [Prod.map_mk, nhds_prod_eq, ← map_mk_nhds, ← map_mk_nhds, Filter.prod_map_map_eq',
← nhds_prod_eq, Filter.mem_map]
exact hs.mem_nhds h
def lift (f : X → α) (hf : ∀ x y, (x ~ᵢ y) → f x = f y) : SeparationQuotient X → α := fun x =>
Quotient.liftOn' x f hf
#align separation_quotient.lift SeparationQuotient.lift
@[simp]
theorem lift_mk {f : X → α} (hf : ∀ x y, (x ~ᵢ y) → f x = f y) (x : X) : lift f hf (mk x) = f x :=
rfl
#align separation_quotient.lift_mk SeparationQuotient.lift_mk
@[simp]
theorem lift_comp_mk {f : X → α} (hf : ∀ x y, (x ~ᵢ y) → f x = f y) : lift f hf ∘ mk = f :=
rfl
#align separation_quotient.lift_comp_mk SeparationQuotient.lift_comp_mk
@[simp]
| Mathlib/Topology/Inseparable.lean | 519 | 521 | theorem tendsto_lift_nhds_mk {f : X → α} {hf : ∀ x y, (x ~ᵢ y) → f x = f y} {l : Filter α} :
Tendsto (lift f hf) (𝓝 <| mk x) l ↔ Tendsto f (𝓝 x) l := by |
simp only [← map_mk_nhds, tendsto_map'_iff, lift_comp_mk]
|
import Mathlib.MeasureTheory.Integral.SetToL1
#align_import measure_theory.integral.bochner from "leanprover-community/mathlib"@"48fb5b5280e7c81672afc9524185ae994553ebf4"
assert_not_exists Differentiable
noncomputable section
open scoped Topology NNReal ENNReal MeasureTheory
open Set Filter TopologicalSpace ENNReal EMetric
namespace MeasureTheory
variable {α E F 𝕜 : Type*}
local infixr:25 " →ₛ " => SimpleFunc
namespace SimpleFunc
section Integral
open Finset
variable [NormedAddCommGroup E] [NormedAddCommGroup F] [NormedSpace ℝ F] {p : ℝ≥0∞} {G F' : Type*}
[NormedAddCommGroup G] [NormedAddCommGroup F'] [NormedSpace ℝ F'] {m : MeasurableSpace α}
{μ : Measure α}
def integral {_ : MeasurableSpace α} (μ : Measure α) (f : α →ₛ F) : F :=
f.setToSimpleFunc (weightedSMul μ)
#align measure_theory.simple_func.integral MeasureTheory.SimpleFunc.integral
theorem integral_def {_ : MeasurableSpace α} (μ : Measure α) (f : α →ₛ F) :
f.integral μ = f.setToSimpleFunc (weightedSMul μ) := rfl
#align measure_theory.simple_func.integral_def MeasureTheory.SimpleFunc.integral_def
theorem integral_eq {m : MeasurableSpace α} (μ : Measure α) (f : α →ₛ F) :
f.integral μ = ∑ x ∈ f.range, (μ (f ⁻¹' {x})).toReal • x := by
simp [integral, setToSimpleFunc, weightedSMul_apply]
#align measure_theory.simple_func.integral_eq MeasureTheory.SimpleFunc.integral_eq
theorem integral_eq_sum_filter [DecidablePred fun x : F => x ≠ 0] {m : MeasurableSpace α}
(f : α →ₛ F) (μ : Measure α) :
f.integral μ = ∑ x ∈ f.range.filter fun x => x ≠ 0, (μ (f ⁻¹' {x})).toReal • x := by
rw [integral_def, setToSimpleFunc_eq_sum_filter]; simp_rw [weightedSMul_apply]; congr
#align measure_theory.simple_func.integral_eq_sum_filter MeasureTheory.SimpleFunc.integral_eq_sum_filter
theorem integral_eq_sum_of_subset [DecidablePred fun x : F => x ≠ 0] {f : α →ₛ F} {s : Finset F}
(hs : (f.range.filter fun x => x ≠ 0) ⊆ s) :
f.integral μ = ∑ x ∈ s, (μ (f ⁻¹' {x})).toReal • x := by
rw [SimpleFunc.integral_eq_sum_filter, Finset.sum_subset hs]
rintro x - hx; rw [Finset.mem_filter, not_and_or, Ne, Classical.not_not] at hx
-- Porting note: reordered for clarity
rcases hx.symm with (rfl | hx)
· simp
rw [SimpleFunc.mem_range] at hx
-- Porting note: added
simp only [Set.mem_range, not_exists] at hx
rw [preimage_eq_empty] <;> simp [Set.disjoint_singleton_left, hx]
#align measure_theory.simple_func.integral_eq_sum_of_subset MeasureTheory.SimpleFunc.integral_eq_sum_of_subset
@[simp]
| Mathlib/MeasureTheory/Integral/Bochner.lean | 344 | 350 | theorem integral_const {m : MeasurableSpace α} (μ : Measure α) (y : F) :
(const α y).integral μ = (μ univ).toReal • y := by |
classical
calc
(const α y).integral μ = ∑ z ∈ {y}, (μ (const α y ⁻¹' {z})).toReal • z :=
integral_eq_sum_of_subset <| (filter_subset _ _).trans (range_const_subset _ _)
_ = (μ univ).toReal • y := by simp [Set.preimage] -- Porting note: added `Set.preimage`
|
import Mathlib.Algebra.CharP.Invertible
import Mathlib.Analysis.NormedSpace.LinearIsometry
import Mathlib.Analysis.Normed.Group.AddTorsor
import Mathlib.Analysis.NormedSpace.Basic
import Mathlib.LinearAlgebra.AffineSpace.Restrict
import Mathlib.Tactic.FailIfNoProgress
#align_import analysis.normed_space.affine_isometry from "leanprover-community/mathlib"@"f0c8bf9245297a541f468be517f1bde6195105e9"
open Function Set
variable (𝕜 : Type*) {V V₁ V₁' V₂ V₃ V₄ : Type*} {P₁ P₁' : Type*} (P P₂ : Type*) {P₃ P₄ : Type*}
[NormedField 𝕜]
[SeminormedAddCommGroup V] [NormedSpace 𝕜 V] [PseudoMetricSpace P] [NormedAddTorsor V P]
[SeminormedAddCommGroup V₁] [NormedSpace 𝕜 V₁] [PseudoMetricSpace P₁] [NormedAddTorsor V₁ P₁]
[SeminormedAddCommGroup V₁'] [NormedSpace 𝕜 V₁'] [MetricSpace P₁'] [NormedAddTorsor V₁' P₁']
[SeminormedAddCommGroup V₂] [NormedSpace 𝕜 V₂] [PseudoMetricSpace P₂] [NormedAddTorsor V₂ P₂]
[SeminormedAddCommGroup V₃] [NormedSpace 𝕜 V₃] [PseudoMetricSpace P₃] [NormedAddTorsor V₃ P₃]
[SeminormedAddCommGroup V₄] [NormedSpace 𝕜 V₄] [PseudoMetricSpace P₄] [NormedAddTorsor V₄ P₄]
structure AffineIsometry extends P →ᵃ[𝕜] P₂ where
norm_map : ∀ x : V, ‖linear x‖ = ‖x‖
#align affine_isometry AffineIsometry
variable {𝕜 P P₂}
@[inherit_doc]
notation:25 -- `→ᵃᵢ` would be more consistent with the linear isometry notation, but it is uglier
P " →ᵃⁱ[" 𝕜:25 "] " P₂:0 => AffineIsometry 𝕜 P P₂
variable (𝕜 P P₂)
structure AffineIsometryEquiv extends P ≃ᵃ[𝕜] P₂ where
norm_map : ∀ x, ‖linear x‖ = ‖x‖
#align affine_isometry_equiv AffineIsometryEquiv
variable {𝕜 P P₂}
-- `≃ᵃᵢ` would be more consistent with the linear isometry equiv notation, but it is uglier
notation:25 P " ≃ᵃⁱ[" 𝕜:25 "] " P₂:0 => AffineIsometryEquiv 𝕜 P P₂
namespace AffineIsometryEquiv
variable (e : P ≃ᵃⁱ[𝕜] P₂)
protected theorem isometry : Isometry e :=
e.toAffineIsometry.isometry
#align affine_isometry_equiv.isometry AffineIsometryEquiv.isometry
def toIsometryEquiv : P ≃ᵢ P₂ :=
⟨e.toAffineEquiv.toEquiv, e.isometry⟩
#align affine_isometry_equiv.to_isometry_equiv AffineIsometryEquiv.toIsometryEquiv
@[simp]
theorem coe_toIsometryEquiv : ⇑e.toIsometryEquiv = e :=
rfl
#align affine_isometry_equiv.coe_to_isometry_equiv AffineIsometryEquiv.coe_toIsometryEquiv
theorem range_eq_univ (e : P ≃ᵃⁱ[𝕜] P₂) : Set.range e = Set.univ := by
rw [← coe_toIsometryEquiv]
exact IsometryEquiv.range_eq_univ _
#align affine_isometry_equiv.range_eq_univ AffineIsometryEquiv.range_eq_univ
def toHomeomorph : P ≃ₜ P₂ :=
e.toIsometryEquiv.toHomeomorph
#align affine_isometry_equiv.to_homeomorph AffineIsometryEquiv.toHomeomorph
@[simp]
theorem coe_toHomeomorph : ⇑e.toHomeomorph = e :=
rfl
#align affine_isometry_equiv.coe_to_homeomorph AffineIsometryEquiv.coe_toHomeomorph
protected theorem continuous : Continuous e :=
e.isometry.continuous
#align affine_isometry_equiv.continuous AffineIsometryEquiv.continuous
protected theorem continuousAt {x} : ContinuousAt e x :=
e.continuous.continuousAt
#align affine_isometry_equiv.continuous_at AffineIsometryEquiv.continuousAt
protected theorem continuousOn {s} : ContinuousOn e s :=
e.continuous.continuousOn
#align affine_isometry_equiv.continuous_on AffineIsometryEquiv.continuousOn
protected theorem continuousWithinAt {s x} : ContinuousWithinAt e s x :=
e.continuous.continuousWithinAt
#align affine_isometry_equiv.continuous_within_at AffineIsometryEquiv.continuousWithinAt
variable (𝕜 P)
def refl : P ≃ᵃⁱ[𝕜] P :=
⟨AffineEquiv.refl 𝕜 P, fun _ => rfl⟩
#align affine_isometry_equiv.refl AffineIsometryEquiv.refl
variable {𝕜 P}
instance : Inhabited (P ≃ᵃⁱ[𝕜] P) :=
⟨refl 𝕜 P⟩
@[simp]
theorem coe_refl : ⇑(refl 𝕜 P) = id :=
rfl
#align affine_isometry_equiv.coe_refl AffineIsometryEquiv.coe_refl
@[simp]
theorem toAffineEquiv_refl : (refl 𝕜 P).toAffineEquiv = AffineEquiv.refl 𝕜 P :=
rfl
#align affine_isometry_equiv.to_affine_equiv_refl AffineIsometryEquiv.toAffineEquiv_refl
@[simp]
theorem toIsometryEquiv_refl : (refl 𝕜 P).toIsometryEquiv = IsometryEquiv.refl P :=
rfl
#align affine_isometry_equiv.to_isometry_equiv_refl AffineIsometryEquiv.toIsometryEquiv_refl
@[simp]
theorem toHomeomorph_refl : (refl 𝕜 P).toHomeomorph = Homeomorph.refl P :=
rfl
#align affine_isometry_equiv.to_homeomorph_refl AffineIsometryEquiv.toHomeomorph_refl
def symm : P₂ ≃ᵃⁱ[𝕜] P :=
{ e.toAffineEquiv.symm with norm_map := e.linearIsometryEquiv.symm.norm_map }
#align affine_isometry_equiv.symm AffineIsometryEquiv.symm
@[simp]
theorem apply_symm_apply (x : P₂) : e (e.symm x) = x :=
e.toAffineEquiv.apply_symm_apply x
#align affine_isometry_equiv.apply_symm_apply AffineIsometryEquiv.apply_symm_apply
@[simp]
theorem symm_apply_apply (x : P) : e.symm (e x) = x :=
e.toAffineEquiv.symm_apply_apply x
#align affine_isometry_equiv.symm_apply_apply AffineIsometryEquiv.symm_apply_apply
@[simp]
theorem symm_symm : e.symm.symm = e :=
ext fun _ => rfl
#align affine_isometry_equiv.symm_symm AffineIsometryEquiv.symm_symm
@[simp]
theorem toAffineEquiv_symm : e.toAffineEquiv.symm = e.symm.toAffineEquiv :=
rfl
#align affine_isometry_equiv.to_affine_equiv_symm AffineIsometryEquiv.toAffineEquiv_symm
@[simp]
theorem toIsometryEquiv_symm : e.toIsometryEquiv.symm = e.symm.toIsometryEquiv :=
rfl
#align affine_isometry_equiv.to_isometry_equiv_symm AffineIsometryEquiv.toIsometryEquiv_symm
@[simp]
theorem toHomeomorph_symm : e.toHomeomorph.symm = e.symm.toHomeomorph :=
rfl
#align affine_isometry_equiv.to_homeomorph_symm AffineIsometryEquiv.toHomeomorph_symm
def trans (e' : P₂ ≃ᵃⁱ[𝕜] P₃) : P ≃ᵃⁱ[𝕜] P₃ :=
⟨e.toAffineEquiv.trans e'.toAffineEquiv, fun _ => (e'.norm_map _).trans (e.norm_map _)⟩
#align affine_isometry_equiv.trans AffineIsometryEquiv.trans
@[simp]
theorem coe_trans (e₁ : P ≃ᵃⁱ[𝕜] P₂) (e₂ : P₂ ≃ᵃⁱ[𝕜] P₃) : ⇑(e₁.trans e₂) = e₂ ∘ e₁ :=
rfl
#align affine_isometry_equiv.coe_trans AffineIsometryEquiv.coe_trans
@[simp]
theorem trans_refl : e.trans (refl 𝕜 P₂) = e :=
ext fun _ => rfl
#align affine_isometry_equiv.trans_refl AffineIsometryEquiv.trans_refl
@[simp]
theorem refl_trans : (refl 𝕜 P).trans e = e :=
ext fun _ => rfl
#align affine_isometry_equiv.refl_trans AffineIsometryEquiv.refl_trans
@[simp]
theorem self_trans_symm : e.trans e.symm = refl 𝕜 P :=
ext e.symm_apply_apply
#align affine_isometry_equiv.self_trans_symm AffineIsometryEquiv.self_trans_symm
@[simp]
theorem symm_trans_self : e.symm.trans e = refl 𝕜 P₂ :=
ext e.apply_symm_apply
#align affine_isometry_equiv.symm_trans_self AffineIsometryEquiv.symm_trans_self
@[simp]
theorem coe_symm_trans (e₁ : P ≃ᵃⁱ[𝕜] P₂) (e₂ : P₂ ≃ᵃⁱ[𝕜] P₃) :
⇑(e₁.trans e₂).symm = e₁.symm ∘ e₂.symm :=
rfl
#align affine_isometry_equiv.coe_symm_trans AffineIsometryEquiv.coe_symm_trans
theorem trans_assoc (ePP₂ : P ≃ᵃⁱ[𝕜] P₂) (eP₂G : P₂ ≃ᵃⁱ[𝕜] P₃) (eGG' : P₃ ≃ᵃⁱ[𝕜] P₄) :
ePP₂.trans (eP₂G.trans eGG') = (ePP₂.trans eP₂G).trans eGG' :=
rfl
#align affine_isometry_equiv.trans_assoc AffineIsometryEquiv.trans_assoc
instance instGroup : Group (P ≃ᵃⁱ[𝕜] P) where
mul e₁ e₂ := e₂.trans e₁
one := refl _ _
inv := symm
one_mul := trans_refl
mul_one := refl_trans
mul_assoc _ _ _ := trans_assoc _ _ _
mul_left_inv := self_trans_symm
@[simp]
theorem coe_one : ⇑(1 : P ≃ᵃⁱ[𝕜] P) = id :=
rfl
#align affine_isometry_equiv.coe_one AffineIsometryEquiv.coe_one
@[simp]
theorem coe_mul (e e' : P ≃ᵃⁱ[𝕜] P) : ⇑(e * e') = e ∘ e' :=
rfl
#align affine_isometry_equiv.coe_mul AffineIsometryEquiv.coe_mul
@[simp]
theorem coe_inv (e : P ≃ᵃⁱ[𝕜] P) : ⇑e⁻¹ = e.symm :=
rfl
#align affine_isometry_equiv.coe_inv AffineIsometryEquiv.coe_inv
@[simp]
theorem map_vadd (p : P) (v : V) : e (v +ᵥ p) = e.linearIsometryEquiv v +ᵥ e p :=
e.toAffineIsometry.map_vadd p v
#align affine_isometry_equiv.map_vadd AffineIsometryEquiv.map_vadd
@[simp]
theorem map_vsub (p1 p2 : P) : e.linearIsometryEquiv (p1 -ᵥ p2) = e p1 -ᵥ e p2 :=
e.toAffineIsometry.map_vsub p1 p2
#align affine_isometry_equiv.map_vsub AffineIsometryEquiv.map_vsub
@[simp]
theorem dist_map (x y : P) : dist (e x) (e y) = dist x y :=
e.toAffineIsometry.dist_map x y
#align affine_isometry_equiv.dist_map AffineIsometryEquiv.dist_map
@[simp]
theorem edist_map (x y : P) : edist (e x) (e y) = edist x y :=
e.toAffineIsometry.edist_map x y
#align affine_isometry_equiv.edist_map AffineIsometryEquiv.edist_map
protected theorem bijective : Bijective e :=
e.1.bijective
#align affine_isometry_equiv.bijective AffineIsometryEquiv.bijective
protected theorem injective : Injective e :=
e.1.injective
#align affine_isometry_equiv.injective AffineIsometryEquiv.injective
protected theorem surjective : Surjective e :=
e.1.surjective
#align affine_isometry_equiv.surjective AffineIsometryEquiv.surjective
-- @[simp] Porting note (#10618): simp can prove this
theorem map_eq_iff {x y : P} : e x = e y ↔ x = y :=
e.injective.eq_iff
#align affine_isometry_equiv.map_eq_iff AffineIsometryEquiv.map_eq_iff
theorem map_ne {x y : P} (h : x ≠ y) : e x ≠ e y :=
e.injective.ne h
#align affine_isometry_equiv.map_ne AffineIsometryEquiv.map_ne
protected theorem lipschitz : LipschitzWith 1 e :=
e.isometry.lipschitz
#align affine_isometry_equiv.lipschitz AffineIsometryEquiv.lipschitz
protected theorem antilipschitz : AntilipschitzWith 1 e :=
e.isometry.antilipschitz
#align affine_isometry_equiv.antilipschitz AffineIsometryEquiv.antilipschitz
@[simp]
theorem ediam_image (s : Set P) : EMetric.diam (e '' s) = EMetric.diam s :=
e.isometry.ediam_image s
#align affine_isometry_equiv.ediam_image AffineIsometryEquiv.ediam_image
@[simp]
theorem diam_image (s : Set P) : Metric.diam (e '' s) = Metric.diam s :=
e.isometry.diam_image s
#align affine_isometry_equiv.diam_image AffineIsometryEquiv.diam_image
variable {α : Type*} [TopologicalSpace α]
@[simp]
theorem comp_continuousOn_iff {f : α → P} {s : Set α} : ContinuousOn (e ∘ f) s ↔ ContinuousOn f s :=
e.isometry.comp_continuousOn_iff
#align affine_isometry_equiv.comp_continuous_on_iff AffineIsometryEquiv.comp_continuousOn_iff
@[simp]
theorem comp_continuous_iff {f : α → P} : Continuous (e ∘ f) ↔ Continuous f :=
e.isometry.comp_continuous_iff
#align affine_isometry_equiv.comp_continuous_iff AffineIsometryEquiv.comp_continuous_iff
theorem AffineMap.continuous_linear_iff {f : P →ᵃ[𝕜] P₂} : Continuous f.linear ↔ Continuous f := by
inhabit P
have :
(f.linear : V → V₂) =
(AffineIsometryEquiv.vaddConst 𝕜 <| f default).toHomeomorph.symm ∘
f ∘ (AffineIsometryEquiv.vaddConst 𝕜 default).toHomeomorph := by
ext v
simp
rw [this]
simp only [Homeomorph.comp_continuous_iff, Homeomorph.comp_continuous_iff']
#align affine_map.continuous_linear_iff AffineMap.continuous_linear_iff
| Mathlib/Analysis/NormedSpace/AffineIsometry.lean | 858 | 867 | theorem AffineMap.isOpenMap_linear_iff {f : P →ᵃ[𝕜] P₂} : IsOpenMap f.linear ↔ IsOpenMap f := by |
inhabit P
have :
(f.linear : V → V₂) =
(AffineIsometryEquiv.vaddConst 𝕜 <| f default).toHomeomorph.symm ∘
f ∘ (AffineIsometryEquiv.vaddConst 𝕜 default).toHomeomorph := by
ext v
simp
rw [this]
simp only [Homeomorph.comp_isOpenMap_iff, Homeomorph.comp_isOpenMap_iff']
|
import Mathlib.LinearAlgebra.AffineSpace.AffineEquiv
#align_import linear_algebra.affine_space.affine_subspace from "leanprover-community/mathlib"@"e96bdfbd1e8c98a09ff75f7ac6204d142debc840"
noncomputable section
open Affine
open Set
section
variable (k : Type*) {V : Type*} {P : Type*} [Ring k] [AddCommGroup V] [Module k V]
variable [AffineSpace V P]
def vectorSpan (s : Set P) : Submodule k V :=
Submodule.span k (s -ᵥ s)
#align vector_span vectorSpan
theorem vectorSpan_def (s : Set P) : vectorSpan k s = Submodule.span k (s -ᵥ s) :=
rfl
#align vector_span_def vectorSpan_def
theorem vectorSpan_mono {s₁ s₂ : Set P} (h : s₁ ⊆ s₂) : vectorSpan k s₁ ≤ vectorSpan k s₂ :=
Submodule.span_mono (vsub_self_mono h)
#align vector_span_mono vectorSpan_mono
variable (P)
@[simp]
theorem vectorSpan_empty : vectorSpan k (∅ : Set P) = (⊥ : Submodule k V) := by
rw [vectorSpan_def, vsub_empty, Submodule.span_empty]
#align vector_span_empty vectorSpan_empty
variable {P}
@[simp]
theorem vectorSpan_singleton (p : P) : vectorSpan k ({p} : Set P) = ⊥ := by simp [vectorSpan_def]
#align vector_span_singleton vectorSpan_singleton
theorem vsub_set_subset_vectorSpan (s : Set P) : s -ᵥ s ⊆ ↑(vectorSpan k s) :=
Submodule.subset_span
#align vsub_set_subset_vector_span vsub_set_subset_vectorSpan
theorem vsub_mem_vectorSpan {s : Set P} {p1 p2 : P} (hp1 : p1 ∈ s) (hp2 : p2 ∈ s) :
p1 -ᵥ p2 ∈ vectorSpan k s :=
vsub_set_subset_vectorSpan k s (vsub_mem_vsub hp1 hp2)
#align vsub_mem_vector_span vsub_mem_vectorSpan
def spanPoints (s : Set P) : Set P :=
{ p | ∃ p1 ∈ s, ∃ v ∈ vectorSpan k s, p = v +ᵥ p1 }
#align span_points spanPoints
theorem mem_spanPoints (p : P) (s : Set P) : p ∈ s → p ∈ spanPoints k s
| hp => ⟨p, hp, 0, Submodule.zero_mem _, (zero_vadd V p).symm⟩
#align mem_span_points mem_spanPoints
theorem subset_spanPoints (s : Set P) : s ⊆ spanPoints k s := fun p => mem_spanPoints k p s
#align subset_span_points subset_spanPoints
@[simp]
theorem spanPoints_nonempty (s : Set P) : (spanPoints k s).Nonempty ↔ s.Nonempty := by
constructor
· contrapose
rw [Set.not_nonempty_iff_eq_empty, Set.not_nonempty_iff_eq_empty]
intro h
simp [h, spanPoints]
· exact fun h => h.mono (subset_spanPoints _ _)
#align span_points_nonempty spanPoints_nonempty
theorem vadd_mem_spanPoints_of_mem_spanPoints_of_mem_vectorSpan {s : Set P} {p : P} {v : V}
(hp : p ∈ spanPoints k s) (hv : v ∈ vectorSpan k s) : v +ᵥ p ∈ spanPoints k s := by
rcases hp with ⟨p2, ⟨hp2, ⟨v2, ⟨hv2, hv2p⟩⟩⟩⟩
rw [hv2p, vadd_vadd]
exact ⟨p2, hp2, v + v2, (vectorSpan k s).add_mem hv hv2, rfl⟩
#align vadd_mem_span_points_of_mem_span_points_of_mem_vector_span vadd_mem_spanPoints_of_mem_spanPoints_of_mem_vectorSpan
theorem vsub_mem_vectorSpan_of_mem_spanPoints_of_mem_spanPoints {s : Set P} {p1 p2 : P}
(hp1 : p1 ∈ spanPoints k s) (hp2 : p2 ∈ spanPoints k s) : p1 -ᵥ p2 ∈ vectorSpan k s := by
rcases hp1 with ⟨p1a, ⟨hp1a, ⟨v1, ⟨hv1, hv1p⟩⟩⟩⟩
rcases hp2 with ⟨p2a, ⟨hp2a, ⟨v2, ⟨hv2, hv2p⟩⟩⟩⟩
rw [hv1p, hv2p, vsub_vadd_eq_vsub_sub (v1 +ᵥ p1a), vadd_vsub_assoc, add_comm, add_sub_assoc]
have hv1v2 : v1 - v2 ∈ vectorSpan k s := (vectorSpan k s).sub_mem hv1 hv2
refine (vectorSpan k s).add_mem ?_ hv1v2
exact vsub_mem_vectorSpan k hp1a hp2a
#align vsub_mem_vector_span_of_mem_span_points_of_mem_span_points vsub_mem_vectorSpan_of_mem_spanPoints_of_mem_spanPoints
end
structure AffineSubspace (k : Type*) {V : Type*} (P : Type*) [Ring k] [AddCommGroup V]
[Module k V] [AffineSpace V P] where
carrier : Set P
smul_vsub_vadd_mem :
∀ (c : k) {p1 p2 p3 : P},
p1 ∈ carrier → p2 ∈ carrier → p3 ∈ carrier → c • (p1 -ᵥ p2 : V) +ᵥ p3 ∈ carrier
#align affine_subspace AffineSubspace
theorem AffineMap.lineMap_mem {k V P : Type*} [Ring k] [AddCommGroup V] [Module k V]
[AddTorsor V P] {Q : AffineSubspace k P} {p₀ p₁ : P} (c : k) (h₀ : p₀ ∈ Q) (h₁ : p₁ ∈ Q) :
AffineMap.lineMap p₀ p₁ c ∈ Q := by
rw [AffineMap.lineMap_apply]
exact Q.smul_vsub_vadd_mem c h₁ h₀ h₀
#align affine_map.line_map_mem AffineMap.lineMap_mem
namespace AffineSubspace
variable {k : Type*} {V : Type*} {P : Type*} [Ring k] [AddCommGroup V] [Module k V]
[S : AffineSpace V P]
instance : CompleteLattice (AffineSubspace k P) :=
{
PartialOrder.lift ((↑) : AffineSubspace k P → Set P)
coe_injective with
sup := fun s1 s2 => affineSpan k (s1 ∪ s2)
le_sup_left := fun s1 s2 =>
Set.Subset.trans Set.subset_union_left (subset_spanPoints k _)
le_sup_right := fun s1 s2 =>
Set.Subset.trans Set.subset_union_right (subset_spanPoints k _)
sup_le := fun s1 s2 s3 hs1 hs2 => spanPoints_subset_coe_of_subset_coe (Set.union_subset hs1 hs2)
inf := fun s1 s2 =>
mk (s1 ∩ s2) fun c p1 p2 p3 hp1 hp2 hp3 =>
⟨s1.smul_vsub_vadd_mem c hp1.1 hp2.1 hp3.1, s2.smul_vsub_vadd_mem c hp1.2 hp2.2 hp3.2⟩
inf_le_left := fun _ _ => Set.inter_subset_left
inf_le_right := fun _ _ => Set.inter_subset_right
le_sInf := fun S s1 hs1 => by
-- Porting note: surely there is an easier way?
refine Set.subset_sInter (t := (s1 : Set P)) ?_
rintro t ⟨s, _hs, rfl⟩
exact Set.subset_iInter (hs1 s)
top :=
{ carrier := Set.univ
smul_vsub_vadd_mem := fun _ _ _ _ _ _ _ => Set.mem_univ _ }
le_top := fun _ _ _ => Set.mem_univ _
bot :=
{ carrier := ∅
smul_vsub_vadd_mem := fun _ _ _ _ => False.elim }
bot_le := fun _ _ => False.elim
sSup := fun s => affineSpan k (⋃ s' ∈ s, (s' : Set P))
sInf := fun s =>
mk (⋂ s' ∈ s, (s' : Set P)) fun c p1 p2 p3 hp1 hp2 hp3 =>
Set.mem_iInter₂.2 fun s2 hs2 => by
rw [Set.mem_iInter₂] at *
exact s2.smul_vsub_vadd_mem c (hp1 s2 hs2) (hp2 s2 hs2) (hp3 s2 hs2)
le_sSup := fun _ _ h => Set.Subset.trans (Set.subset_biUnion_of_mem h) (subset_spanPoints k _)
sSup_le := fun _ _ h => spanPoints_subset_coe_of_subset_coe (Set.iUnion₂_subset h)
sInf_le := fun _ _ => Set.biInter_subset_of_mem
le_inf := fun _ _ _ => Set.subset_inter }
instance : Inhabited (AffineSubspace k P) :=
⟨⊤⟩
theorem le_def (s1 s2 : AffineSubspace k P) : s1 ≤ s2 ↔ (s1 : Set P) ⊆ s2 :=
Iff.rfl
#align affine_subspace.le_def AffineSubspace.le_def
theorem le_def' (s1 s2 : AffineSubspace k P) : s1 ≤ s2 ↔ ∀ p ∈ s1, p ∈ s2 :=
Iff.rfl
#align affine_subspace.le_def' AffineSubspace.le_def'
theorem lt_def (s1 s2 : AffineSubspace k P) : s1 < s2 ↔ (s1 : Set P) ⊂ s2 :=
Iff.rfl
#align affine_subspace.lt_def AffineSubspace.lt_def
theorem not_le_iff_exists (s1 s2 : AffineSubspace k P) : ¬s1 ≤ s2 ↔ ∃ p ∈ s1, p ∉ s2 :=
Set.not_subset
#align affine_subspace.not_le_iff_exists AffineSubspace.not_le_iff_exists
theorem exists_of_lt {s1 s2 : AffineSubspace k P} (h : s1 < s2) : ∃ p ∈ s2, p ∉ s1 :=
Set.exists_of_ssubset h
#align affine_subspace.exists_of_lt AffineSubspace.exists_of_lt
theorem lt_iff_le_and_exists (s1 s2 : AffineSubspace k P) :
s1 < s2 ↔ s1 ≤ s2 ∧ ∃ p ∈ s2, p ∉ s1 := by
rw [lt_iff_le_not_le, not_le_iff_exists]
#align affine_subspace.lt_iff_le_and_exists AffineSubspace.lt_iff_le_and_exists
theorem eq_of_direction_eq_of_nonempty_of_le {s₁ s₂ : AffineSubspace k P}
(hd : s₁.direction = s₂.direction) (hn : (s₁ : Set P).Nonempty) (hle : s₁ ≤ s₂) : s₁ = s₂ :=
let ⟨p, hp⟩ := hn
ext_of_direction_eq hd ⟨p, hp, hle hp⟩
#align affine_subspace.eq_of_direction_eq_of_nonempty_of_le AffineSubspace.eq_of_direction_eq_of_nonempty_of_le
variable (k V)
theorem affineSpan_eq_sInf (s : Set P) :
affineSpan k s = sInf { s' : AffineSubspace k P | s ⊆ s' } :=
le_antisymm (spanPoints_subset_coe_of_subset_coe <| Set.subset_iInter₂ fun _ => id)
(sInf_le (subset_spanPoints k _))
#align affine_subspace.affine_span_eq_Inf AffineSubspace.affineSpan_eq_sInf
variable (P)
protected def gi : GaloisInsertion (affineSpan k) ((↑) : AffineSubspace k P → Set P) where
choice s _ := affineSpan k s
gc s1 _s2 :=
⟨fun h => Set.Subset.trans (subset_spanPoints k s1) h, spanPoints_subset_coe_of_subset_coe⟩
le_l_u _ := subset_spanPoints k _
choice_eq _ _ := rfl
#align affine_subspace.gi AffineSubspace.gi
@[simp]
theorem span_empty : affineSpan k (∅ : Set P) = ⊥ :=
(AffineSubspace.gi k V P).gc.l_bot
#align affine_subspace.span_empty AffineSubspace.span_empty
@[simp]
theorem span_univ : affineSpan k (Set.univ : Set P) = ⊤ :=
eq_top_iff.2 <| subset_spanPoints k _
#align affine_subspace.span_univ AffineSubspace.span_univ
variable {k V P}
theorem _root_.affineSpan_le {s : Set P} {Q : AffineSubspace k P} :
affineSpan k s ≤ Q ↔ s ⊆ (Q : Set P) :=
(AffineSubspace.gi k V P).gc _ _
#align affine_span_le affineSpan_le
variable (k V) {p₁ p₂ : P}
@[simp 1001] -- Porting note: this needs to take priority over `coe_affineSpan`
theorem coe_affineSpan_singleton (p : P) : (affineSpan k ({p} : Set P) : Set P) = {p} := by
ext x
rw [mem_coe, ← vsub_right_mem_direction_iff_mem (mem_affineSpan k (Set.mem_singleton p)) _,
direction_affineSpan]
simp
#align affine_subspace.coe_affine_span_singleton AffineSubspace.coe_affineSpan_singleton
@[simp]
theorem mem_affineSpan_singleton : p₁ ∈ affineSpan k ({p₂} : Set P) ↔ p₁ = p₂ := by
simp [← mem_coe]
#align affine_subspace.mem_affine_span_singleton AffineSubspace.mem_affineSpan_singleton
@[simp]
theorem preimage_coe_affineSpan_singleton (x : P) :
((↑) : affineSpan k ({x} : Set P) → P) ⁻¹' {x} = univ :=
eq_univ_of_forall fun y => (AffineSubspace.mem_affineSpan_singleton _ _).1 y.2
#align affine_subspace.preimage_coe_affine_span_singleton AffineSubspace.preimage_coe_affineSpan_singleton
theorem span_union (s t : Set P) : affineSpan k (s ∪ t) = affineSpan k s ⊔ affineSpan k t :=
(AffineSubspace.gi k V P).gc.l_sup
#align affine_subspace.span_union AffineSubspace.span_union
theorem span_iUnion {ι : Type*} (s : ι → Set P) :
affineSpan k (⋃ i, s i) = ⨆ i, affineSpan k (s i) :=
(AffineSubspace.gi k V P).gc.l_iSup
#align affine_subspace.span_Union AffineSubspace.span_iUnion
variable (P)
@[simp]
theorem top_coe : ((⊤ : AffineSubspace k P) : Set P) = Set.univ :=
rfl
#align affine_subspace.top_coe AffineSubspace.top_coe
variable {P}
@[simp]
theorem mem_top (p : P) : p ∈ (⊤ : AffineSubspace k P) :=
Set.mem_univ p
#align affine_subspace.mem_top AffineSubspace.mem_top
variable (P)
@[simp]
theorem direction_top : (⊤ : AffineSubspace k P).direction = ⊤ := by
cases' S.nonempty with p
ext v
refine ⟨imp_intro Submodule.mem_top, fun _hv => ?_⟩
have hpv : (v +ᵥ p -ᵥ p : V) ∈ (⊤ : AffineSubspace k P).direction :=
vsub_mem_direction (mem_top k V _) (mem_top k V _)
rwa [vadd_vsub] at hpv
#align affine_subspace.direction_top AffineSubspace.direction_top
@[simp]
theorem bot_coe : ((⊥ : AffineSubspace k P) : Set P) = ∅ :=
rfl
#align affine_subspace.bot_coe AffineSubspace.bot_coe
theorem bot_ne_top : (⊥ : AffineSubspace k P) ≠ ⊤ := by
intro contra
rw [← ext_iff, bot_coe, top_coe] at contra
exact Set.empty_ne_univ contra
#align affine_subspace.bot_ne_top AffineSubspace.bot_ne_top
instance : Nontrivial (AffineSubspace k P) :=
⟨⟨⊥, ⊤, bot_ne_top k V P⟩⟩
theorem nonempty_of_affineSpan_eq_top {s : Set P} (h : affineSpan k s = ⊤) : s.Nonempty := by
rw [Set.nonempty_iff_ne_empty]
rintro rfl
rw [AffineSubspace.span_empty] at h
exact bot_ne_top k V P h
#align affine_subspace.nonempty_of_affine_span_eq_top AffineSubspace.nonempty_of_affineSpan_eq_top
theorem vectorSpan_eq_top_of_affineSpan_eq_top {s : Set P} (h : affineSpan k s = ⊤) :
vectorSpan k s = ⊤ := by rw [← direction_affineSpan, h, direction_top]
#align affine_subspace.vector_span_eq_top_of_affine_span_eq_top AffineSubspace.vectorSpan_eq_top_of_affineSpan_eq_top
theorem affineSpan_eq_top_iff_vectorSpan_eq_top_of_nonempty {s : Set P} (hs : s.Nonempty) :
affineSpan k s = ⊤ ↔ vectorSpan k s = ⊤ := by
refine ⟨vectorSpan_eq_top_of_affineSpan_eq_top k V P, ?_⟩
intro h
suffices Nonempty (affineSpan k s) by
obtain ⟨p, hp : p ∈ affineSpan k s⟩ := this
rw [eq_iff_direction_eq_of_mem hp (mem_top k V p), direction_affineSpan, h, direction_top]
obtain ⟨x, hx⟩ := hs
exact ⟨⟨x, mem_affineSpan k hx⟩⟩
#align affine_subspace.affine_span_eq_top_iff_vector_span_eq_top_of_nonempty AffineSubspace.affineSpan_eq_top_iff_vectorSpan_eq_top_of_nonempty
theorem affineSpan_eq_top_iff_vectorSpan_eq_top_of_nontrivial {s : Set P} [Nontrivial P] :
affineSpan k s = ⊤ ↔ vectorSpan k s = ⊤ := by
rcases s.eq_empty_or_nonempty with hs | hs
· simp [hs, subsingleton_iff_bot_eq_top, AddTorsor.subsingleton_iff V P, not_subsingleton]
· rw [affineSpan_eq_top_iff_vectorSpan_eq_top_of_nonempty k V P hs]
#align affine_subspace.affine_span_eq_top_iff_vector_span_eq_top_of_nontrivial AffineSubspace.affineSpan_eq_top_iff_vectorSpan_eq_top_of_nontrivial
theorem card_pos_of_affineSpan_eq_top {ι : Type*} [Fintype ι] {p : ι → P}
(h : affineSpan k (range p) = ⊤) : 0 < Fintype.card ι := by
obtain ⟨-, ⟨i, -⟩⟩ := nonempty_of_affineSpan_eq_top k V P h
exact Fintype.card_pos_iff.mpr ⟨i⟩
#align affine_subspace.card_pos_of_affine_span_eq_top AffineSubspace.card_pos_of_affineSpan_eq_top
attribute [local instance] toAddTorsor
@[simps! linear apply symm_apply_coe]
def topEquiv : (⊤ : AffineSubspace k P) ≃ᵃ[k] P where
toEquiv := Equiv.Set.univ P
linear := .ofEq _ _ (direction_top _ _ _) ≪≫ₗ Submodule.topEquiv
map_vadd' _p _v := rfl
variable {P}
theorem not_mem_bot (p : P) : p ∉ (⊥ : AffineSubspace k P) :=
Set.not_mem_empty p
#align affine_subspace.not_mem_bot AffineSubspace.not_mem_bot
variable (P)
@[simp]
theorem direction_bot : (⊥ : AffineSubspace k P).direction = ⊥ := by
rw [direction_eq_vectorSpan, bot_coe, vectorSpan_def, vsub_empty, Submodule.span_empty]
#align affine_subspace.direction_bot AffineSubspace.direction_bot
variable {k V P}
@[simp]
theorem coe_eq_bot_iff (Q : AffineSubspace k P) : (Q : Set P) = ∅ ↔ Q = ⊥ :=
coe_injective.eq_iff' (bot_coe _ _ _)
#align affine_subspace.coe_eq_bot_iff AffineSubspace.coe_eq_bot_iff
@[simp]
theorem coe_eq_univ_iff (Q : AffineSubspace k P) : (Q : Set P) = univ ↔ Q = ⊤ :=
coe_injective.eq_iff' (top_coe _ _ _)
#align affine_subspace.coe_eq_univ_iff AffineSubspace.coe_eq_univ_iff
theorem nonempty_iff_ne_bot (Q : AffineSubspace k P) : (Q : Set P).Nonempty ↔ Q ≠ ⊥ := by
rw [nonempty_iff_ne_empty]
exact not_congr Q.coe_eq_bot_iff
#align affine_subspace.nonempty_iff_ne_bot AffineSubspace.nonempty_iff_ne_bot
theorem eq_bot_or_nonempty (Q : AffineSubspace k P) : Q = ⊥ ∨ (Q : Set P).Nonempty := by
rw [nonempty_iff_ne_bot]
apply eq_or_ne
#align affine_subspace.eq_bot_or_nonempty AffineSubspace.eq_bot_or_nonempty
theorem subsingleton_of_subsingleton_span_eq_top {s : Set P} (h₁ : s.Subsingleton)
(h₂ : affineSpan k s = ⊤) : Subsingleton P := by
obtain ⟨p, hp⟩ := AffineSubspace.nonempty_of_affineSpan_eq_top k V P h₂
have : s = {p} := Subset.antisymm (fun q hq => h₁ hq hp) (by simp [hp])
rw [this, ← AffineSubspace.ext_iff, AffineSubspace.coe_affineSpan_singleton,
AffineSubspace.top_coe, eq_comm, ← subsingleton_iff_singleton (mem_univ _)] at h₂
exact subsingleton_of_univ_subsingleton h₂
#align affine_subspace.subsingleton_of_subsingleton_span_eq_top AffineSubspace.subsingleton_of_subsingleton_span_eq_top
theorem eq_univ_of_subsingleton_span_eq_top {s : Set P} (h₁ : s.Subsingleton)
(h₂ : affineSpan k s = ⊤) : s = (univ : Set P) := by
obtain ⟨p, hp⟩ := AffineSubspace.nonempty_of_affineSpan_eq_top k V P h₂
have : s = {p} := Subset.antisymm (fun q hq => h₁ hq hp) (by simp [hp])
rw [this, eq_comm, ← subsingleton_iff_singleton (mem_univ p), subsingleton_univ_iff]
exact subsingleton_of_subsingleton_span_eq_top h₁ h₂
#align affine_subspace.eq_univ_of_subsingleton_span_eq_top AffineSubspace.eq_univ_of_subsingleton_span_eq_top
@[simp]
theorem direction_eq_top_iff_of_nonempty {s : AffineSubspace k P} (h : (s : Set P).Nonempty) :
s.direction = ⊤ ↔ s = ⊤ := by
constructor
· intro hd
rw [← direction_top k V P] at hd
refine ext_of_direction_eq hd ?_
simp [h]
· rintro rfl
simp
#align affine_subspace.direction_eq_top_iff_of_nonempty AffineSubspace.direction_eq_top_iff_of_nonempty
@[simp]
theorem inf_coe (s1 s2 : AffineSubspace k P) : (s1 ⊓ s2 : Set P) = (s1 : Set P) ∩ s2 :=
rfl
#align affine_subspace.inf_coe AffineSubspace.inf_coe
theorem mem_inf_iff (p : P) (s1 s2 : AffineSubspace k P) : p ∈ s1 ⊓ s2 ↔ p ∈ s1 ∧ p ∈ s2 :=
Iff.rfl
#align affine_subspace.mem_inf_iff AffineSubspace.mem_inf_iff
theorem direction_inf (s1 s2 : AffineSubspace k P) :
(s1 ⊓ s2).direction ≤ s1.direction ⊓ s2.direction := by
simp only [direction_eq_vectorSpan, vectorSpan_def]
exact
le_inf (sInf_le_sInf fun p hp => trans (vsub_self_mono inter_subset_left) hp)
(sInf_le_sInf fun p hp => trans (vsub_self_mono inter_subset_right) hp)
#align affine_subspace.direction_inf AffineSubspace.direction_inf
theorem direction_inf_of_mem {s₁ s₂ : AffineSubspace k P} {p : P} (h₁ : p ∈ s₁) (h₂ : p ∈ s₂) :
(s₁ ⊓ s₂).direction = s₁.direction ⊓ s₂.direction := by
ext v
rw [Submodule.mem_inf, ← vadd_mem_iff_mem_direction v h₁, ← vadd_mem_iff_mem_direction v h₂, ←
vadd_mem_iff_mem_direction v ((mem_inf_iff p s₁ s₂).2 ⟨h₁, h₂⟩), mem_inf_iff]
#align affine_subspace.direction_inf_of_mem AffineSubspace.direction_inf_of_mem
theorem direction_inf_of_mem_inf {s₁ s₂ : AffineSubspace k P} {p : P} (h : p ∈ s₁ ⊓ s₂) :
(s₁ ⊓ s₂).direction = s₁.direction ⊓ s₂.direction :=
direction_inf_of_mem ((mem_inf_iff p s₁ s₂).1 h).1 ((mem_inf_iff p s₁ s₂).1 h).2
#align affine_subspace.direction_inf_of_mem_inf AffineSubspace.direction_inf_of_mem_inf
| Mathlib/LinearAlgebra/AffineSpace/AffineSubspace.lean | 939 | 941 | theorem direction_le {s1 s2 : AffineSubspace k P} (h : s1 ≤ s2) : s1.direction ≤ s2.direction := by |
simp only [direction_eq_vectorSpan, vectorSpan_def]
exact vectorSpan_mono k h
|
import Mathlib.Data.Set.Card
import Mathlib.Order.Minimal
import Mathlib.Data.Matroid.Init
set_option autoImplicit true
open Set
def Matroid.ExchangeProperty {α : Type _} (P : Set α → Prop) : Prop :=
∀ X Y, P X → P Y → ∀ a ∈ X \ Y, ∃ b ∈ Y \ X, P (insert b (X \ {a}))
def Matroid.ExistsMaximalSubsetProperty {α : Type _} (P : Set α → Prop) (X : Set α) : Prop :=
∀ I, P I → I ⊆ X → (maximals (· ⊆ ·) {Y | P Y ∧ I ⊆ Y ∧ Y ⊆ X}).Nonempty
@[ext] structure Matroid (α : Type _) where
(E : Set α)
(Base : Set α → Prop)
(Indep : Set α → Prop)
(indep_iff' : ∀ ⦃I⦄, Indep I ↔ ∃ B, Base B ∧ I ⊆ B)
(exists_base : ∃ B, Base B)
(base_exchange : Matroid.ExchangeProperty Base)
(maximality : ∀ X, X ⊆ E → Matroid.ExistsMaximalSubsetProperty Indep X)
(subset_ground : ∀ B, Base B → B ⊆ E)
namespace Matroid
variable {α : Type*} {M : Matroid α}
protected class Finite (M : Matroid α) : Prop where
(ground_finite : M.E.Finite)
protected class Nonempty (M : Matroid α) : Prop where
(ground_nonempty : M.E.Nonempty)
theorem ground_nonempty (M : Matroid α) [M.Nonempty] : M.E.Nonempty :=
Nonempty.ground_nonempty
theorem ground_nonempty_iff (M : Matroid α) : M.E.Nonempty ↔ M.Nonempty :=
⟨fun h ↦ ⟨h⟩, fun ⟨h⟩ ↦ h⟩
theorem ground_finite (M : Matroid α) [M.Finite] : M.E.Finite :=
Finite.ground_finite
theorem set_finite (M : Matroid α) [M.Finite] (X : Set α) (hX : X ⊆ M.E := by aesop) : X.Finite :=
M.ground_finite.subset hX
instance finite_of_finite [Finite α] {M : Matroid α} : M.Finite :=
⟨Set.toFinite _⟩
class FiniteRk (M : Matroid α) : Prop where
exists_finite_base : ∃ B, M.Base B ∧ B.Finite
instance finiteRk_of_finite (M : Matroid α) [M.Finite] : FiniteRk M :=
⟨M.exists_base.imp (fun B hB ↦ ⟨hB, M.set_finite B (M.subset_ground _ hB)⟩)⟩
class InfiniteRk (M : Matroid α) : Prop where
exists_infinite_base : ∃ B, M.Base B ∧ B.Infinite
class RkPos (M : Matroid α) : Prop where
empty_not_base : ¬M.Base ∅
theorem rkPos_iff_empty_not_base : M.RkPos ↔ ¬M.Base ∅ :=
⟨fun ⟨h⟩ ↦ h, fun h ↦ ⟨h⟩⟩
section exchange
section Basis
def Basis (M : Matroid α) (I X : Set α) : Prop :=
I ∈ maximals (· ⊆ ·) {A | M.Indep A ∧ A ⊆ X} ∧ X ⊆ M.E
def Basis' (M : Matroid α) (I X : Set α) : Prop :=
I ∈ maximals (· ⊆ ·) {A | M.Indep A ∧ A ⊆ X}
theorem Basis'.indep (hI : M.Basis' I X) : M.Indep I :=
hI.1.1
theorem Basis.indep (hI : M.Basis I X) : M.Indep I :=
hI.1.1.1
theorem Basis.subset (hI : M.Basis I X) : I ⊆ X :=
hI.1.1.2
theorem Basis.basis' (hI : M.Basis I X) : M.Basis' I X :=
hI.1
theorem Basis'.basis (hI : M.Basis' I X) (hX : X ⊆ M.E := by aesop_mat) : M.Basis I X :=
⟨hI, hX⟩
theorem Basis'.subset (hI : M.Basis' I X) : I ⊆ X :=
hI.1.2
theorem setOf_basis_eq (M : Matroid α) (hX : X ⊆ M.E := by aesop_mat) :
{I | M.Basis I X} = maximals (· ⊆ ·) ({I | M.Indep I} ∩ Iic X) := by
ext I; simp [Matroid.Basis, maximals, iff_true_intro hX]
@[aesop unsafe 15% (rule_sets := [Matroid])]
theorem Basis.subset_ground (hI : M.Basis I X) : X ⊆ M.E :=
hI.2
theorem Basis.basis_inter_ground (hI : M.Basis I X) : M.Basis I (X ∩ M.E) := by
convert hI
rw [inter_eq_self_of_subset_left hI.subset_ground]
@[aesop unsafe 15% (rule_sets := [Matroid])]
theorem Basis.left_subset_ground (hI : M.Basis I X) : I ⊆ M.E :=
hI.indep.subset_ground
theorem Basis.eq_of_subset_indep (hI : M.Basis I X) (hJ : M.Indep J) (hIJ : I ⊆ J) (hJX : J ⊆ X) :
I = J :=
hIJ.antisymm (hI.1.2 ⟨hJ, hJX⟩ hIJ)
theorem Basis.Finite (hI : M.Basis I X) [FiniteRk M] : I.Finite := hI.indep.finite
theorem basis_iff' :
M.Basis I X ↔ (M.Indep I ∧ I ⊆ X ∧ ∀ J, M.Indep J → I ⊆ J → J ⊆ X → I = J) ∧ X ⊆ M.E := by
simp [Basis, mem_maximals_setOf_iff, and_assoc, and_congr_left_iff, and_imp,
and_congr_left_iff, and_congr_right_iff, @Imp.swap (_ ⊆ X)]
theorem basis_iff (hX : X ⊆ M.E := by aesop_mat) :
M.Basis I X ↔ (M.Indep I ∧ I ⊆ X ∧ ∀ J, M.Indep J → I ⊆ J → J ⊆ X → I = J) := by
rw [basis_iff', and_iff_left hX]
theorem basis'_iff_basis_inter_ground : M.Basis' I X ↔ M.Basis I (X ∩ M.E) := by
rw [Basis', Basis, and_iff_left inter_subset_right]
convert Iff.rfl using 3
ext I
simp only [subset_inter_iff, mem_setOf_eq, and_congr_right_iff, and_iff_left_iff_imp]
exact fun h _ ↦ h.subset_ground
theorem basis'_iff_basis (hX : X ⊆ M.E := by aesop_mat) : M.Basis' I X ↔ M.Basis I X := by
rw [basis'_iff_basis_inter_ground, inter_eq_self_of_subset_left hX]
theorem basis_iff_basis'_subset_ground : M.Basis I X ↔ M.Basis' I X ∧ X ⊆ M.E :=
⟨fun h ↦ ⟨h.basis', h.subset_ground⟩, fun h ↦ (basis'_iff_basis h.2).mp h.1⟩
theorem Basis'.basis_inter_ground (hIX : M.Basis' I X) : M.Basis I (X ∩ M.E) :=
basis'_iff_basis_inter_ground.mp hIX
theorem Basis'.eq_of_subset_indep (hI : M.Basis' I X) (hJ : M.Indep J) (hIJ : I ⊆ J)
(hJX : J ⊆ X) : I = J :=
hIJ.antisymm (hI.2 ⟨hJ, hJX⟩ hIJ)
theorem Basis'.insert_not_indep (hI : M.Basis' I X) (he : e ∈ X \ I) : ¬ M.Indep (insert e I) :=
fun hi ↦ he.2 <| insert_eq_self.1 <| Eq.symm <|
hI.eq_of_subset_indep hi (subset_insert _ _) (insert_subset he.1 hI.subset)
theorem basis_iff_mem_maximals (hX : X ⊆ M.E := by aesop_mat):
M.Basis I X ↔ I ∈ maximals (· ⊆ ·) {I | M.Indep I ∧ I ⊆ X} := by
rw [Basis, and_iff_left hX]
theorem basis_iff_mem_maximals_Prop (hX : X ⊆ M.E := by aesop_mat):
M.Basis I X ↔ I ∈ maximals (· ⊆ ·) (fun I ↦ M.Indep I ∧ I ⊆ X) :=
basis_iff_mem_maximals
theorem Indep.basis_of_maximal_subset (hI : M.Indep I) (hIX : I ⊆ X)
(hmax : ∀ ⦃J⦄, M.Indep J → I ⊆ J → J ⊆ X → J ⊆ I) (hX : X ⊆ M.E := by aesop_mat) :
M.Basis I X := by
rw [basis_iff (by aesop_mat : X ⊆ M.E), and_iff_right hI, and_iff_right hIX]
exact fun J hJ hIJ hJX ↦ hIJ.antisymm (hmax hJ hIJ hJX)
theorem Basis.basis_subset (hI : M.Basis I X) (hIY : I ⊆ Y) (hYX : Y ⊆ X) : M.Basis I Y := by
rw [basis_iff (hYX.trans hI.subset_ground), and_iff_right hI.indep, and_iff_right hIY]
exact fun J hJ hIJ hJY ↦ hI.eq_of_subset_indep hJ hIJ (hJY.trans hYX)
@[simp] theorem basis_self_iff_indep : M.Basis I I ↔ M.Indep I := by
rw [basis_iff', and_iff_right rfl.subset, and_assoc, and_iff_left_iff_imp]
exact fun hi ↦ ⟨fun _ _ ↦ subset_antisymm, hi.subset_ground⟩
theorem Indep.basis_self (h : M.Indep I) : M.Basis I I :=
basis_self_iff_indep.mpr h
@[simp] theorem basis_empty_iff (M : Matroid α) : M.Basis I ∅ ↔ I = ∅ :=
⟨fun h ↦ subset_empty_iff.mp h.subset, fun h ↦ by (rw [h]; exact M.empty_indep.basis_self)⟩
theorem Basis.dep_of_ssubset (hI : M.Basis I X) (hIY : I ⊂ Y) (hYX : Y ⊆ X) : M.Dep Y := by
have : X ⊆ M.E := hI.subset_ground
rw [← not_indep_iff]
exact fun hY ↦ hIY.ne (hI.eq_of_subset_indep hY hIY.subset hYX)
theorem Basis.insert_dep (hI : M.Basis I X) (he : e ∈ X \ I) : M.Dep (insert e I) :=
hI.dep_of_ssubset (ssubset_insert he.2) (insert_subset he.1 hI.subset)
theorem Basis.mem_of_insert_indep (hI : M.Basis I X) (he : e ∈ X) (hIe : M.Indep (insert e I)) :
e ∈ I :=
by_contra (fun heI ↦ (hI.insert_dep ⟨he, heI⟩).not_indep hIe)
theorem Basis'.mem_of_insert_indep (hI : M.Basis' I X) (he : e ∈ X) (hIe : M.Indep (insert e I)) :
e ∈ I :=
hI.basis_inter_ground.mem_of_insert_indep ⟨he, hIe.subset_ground (mem_insert _ _)⟩ hIe
theorem Basis.not_basis_of_ssubset (hI : M.Basis I X) (hJI : J ⊂ I) : ¬ M.Basis J X :=
fun h ↦ hJI.ne (h.eq_of_subset_indep hI.indep hJI.subset hI.subset)
theorem Indep.subset_basis_of_subset (hI : M.Indep I) (hIX : I ⊆ X) (hX : X ⊆ M.E := by aesop_mat) :
∃ J, M.Basis J X ∧ I ⊆ J := by
obtain ⟨J, ⟨(hJ : M.Indep J),hIJ,hJX⟩, hJmax⟩ := M.maximality X hX I hI hIX
use J
rw [and_iff_left hIJ, basis_iff, and_iff_right hJ, and_iff_right hJX]
exact fun K hK hJK hKX ↦ hJK.antisymm (hJmax ⟨hK, hIJ.trans hJK, hKX⟩ hJK)
theorem Indep.subset_basis'_of_subset (hI : M.Indep I) (hIX : I ⊆ X) :
∃ J, M.Basis' J X ∧ I ⊆ J := by
simp_rw [basis'_iff_basis_inter_ground]
exact hI.subset_basis_of_subset (subset_inter hIX hI.subset_ground)
theorem exists_basis (M : Matroid α) (X : Set α) (hX : X ⊆ M.E := by aesop_mat) :
∃ I, M.Basis I X :=
let ⟨_, hI, _⟩ := M.empty_indep.subset_basis_of_subset (empty_subset X)
⟨_,hI⟩
theorem exists_basis' (M : Matroid α) (X : Set α) : ∃ I, M.Basis' I X :=
let ⟨_, hI, _⟩ := M.empty_indep.subset_basis'_of_subset (empty_subset X)
⟨_,hI⟩
theorem exists_basis_subset_basis (M : Matroid α) (hXY : X ⊆ Y) (hY : Y ⊆ M.E := by aesop_mat) :
∃ I J, M.Basis I X ∧ M.Basis J Y ∧ I ⊆ J := by
obtain ⟨I, hI⟩ := M.exists_basis X (hXY.trans hY)
obtain ⟨J, hJ, hIJ⟩ := hI.indep.subset_basis_of_subset (hI.subset.trans hXY)
exact ⟨_, _, hI, hJ, hIJ⟩
theorem Basis.exists_basis_inter_eq_of_superset (hI : M.Basis I X) (hXY : X ⊆ Y)
(hY : Y ⊆ M.E := by aesop_mat) : ∃ J, M.Basis J Y ∧ J ∩ X = I := by
obtain ⟨J, hJ, hIJ⟩ := hI.indep.subset_basis_of_subset (hI.subset.trans hXY)
refine ⟨J, hJ, subset_antisymm ?_ (subset_inter hIJ hI.subset)⟩
exact fun e he ↦ hI.mem_of_insert_indep he.2 (hJ.indep.subset (insert_subset he.1 hIJ))
theorem exists_basis_union_inter_basis (M : Matroid α) (X Y : Set α) (hX : X ⊆ M.E := by aesop_mat)
(hY : Y ⊆ M.E := by aesop_mat) : ∃ I, M.Basis I (X ∪ Y) ∧ M.Basis (I ∩ Y) Y :=
let ⟨J, hJ⟩ := M.exists_basis Y
(hJ.exists_basis_inter_eq_of_superset subset_union_right).imp
(fun I hI ↦ ⟨hI.1, by rwa [hI.2]⟩)
theorem Indep.eq_of_basis (hI : M.Indep I) (hJ : M.Basis J I) : J = I :=
hJ.eq_of_subset_indep hI hJ.subset rfl.subset
theorem Basis.exists_base (hI : M.Basis I X) : ∃ B, M.Base B ∧ I = B ∩ X :=
let ⟨B,hB, hIB⟩ := hI.indep.exists_base_superset
⟨B, hB, subset_antisymm (subset_inter hIB hI.subset)
(by rw [hI.eq_of_subset_indep (hB.indep.inter_right X) (subset_inter hIB hI.subset)
inter_subset_right])⟩
@[simp] theorem basis_ground_iff : M.Basis B M.E ↔ M.Base B := by
rw [base_iff_maximal_indep, basis_iff', and_assoc, and_congr_right]
rw [and_iff_left (rfl.subset : M.E ⊆ M.E)]
exact fun h ↦ ⟨fun h' I hI hBI ↦ h'.2 _ hI hBI hI.subset_ground,
fun h' ↦ ⟨h.subset_ground,fun J hJ hBJ _ ↦ h' J hJ hBJ⟩⟩
theorem Base.basis_ground (hB : M.Base B) : M.Basis B M.E :=
basis_ground_iff.mpr hB
theorem Indep.basis_iff_forall_insert_dep (hI : M.Indep I) (hIX : I ⊆ X) :
M.Basis I X ↔ ∀ e ∈ X \ I, M.Dep (insert e I) := by
rw [basis_iff', and_iff_right hIX, and_iff_right hI]
refine ⟨fun h e he ↦ ⟨fun hi ↦ he.2 ?_, insert_subset (h.2 he.1) hI.subset_ground⟩,
fun h ↦ ⟨fun J hJ hIJ hJX ↦ hIJ.antisymm (fun e heJ ↦ by_contra (fun heI ↦ ?_)), ?_⟩⟩
· exact (h.1 _ hi (subset_insert _ _) (insert_subset he.1 hIX)).symm.subset (mem_insert e I)
· exact (h e ⟨hJX heJ, heI⟩).not_indep (hJ.subset (insert_subset heJ hIJ))
rw [← diff_union_of_subset hIX, union_subset_iff, and_iff_left hI.subset_ground]
exact fun e he ↦ (h e he).subset_ground (mem_insert _ _)
theorem Indep.basis_of_forall_insert (hI : M.Indep I) (hIX : I ⊆ X)
(he : ∀ e ∈ X \ I, M.Dep (insert e I)) : M.Basis I X :=
(hI.basis_iff_forall_insert_dep hIX).mpr he
theorem Indep.basis_insert_iff (hI : M.Indep I) :
M.Basis I (insert e I) ↔ M.Dep (insert e I) ∨ e ∈ I := by
simp_rw [hI.basis_iff_forall_insert_dep (subset_insert _ _), dep_iff, insert_subset_iff,
and_iff_left hI.subset_ground, mem_diff, mem_insert_iff, or_and_right, and_not_self,
or_false, and_imp, forall_eq]
tauto
theorem Basis.iUnion_basis_iUnion {ι : Type _} (X I : ι → Set α) (hI : ∀ i, M.Basis (I i) (X i))
(h_ind : M.Indep (⋃ i, I i)) : M.Basis (⋃ i, I i) (⋃ i, X i) := by
refine h_ind.basis_of_forall_insert
(iUnion_subset (fun i ↦ (hI i).subset.trans (subset_iUnion _ _))) ?_
rintro e ⟨⟨_, ⟨⟨i, hi, rfl⟩, (hes : e ∈ X i)⟩⟩, he'⟩
rw [mem_iUnion, not_exists] at he'
refine ((hI i).insert_dep ⟨hes, he' _⟩).superset (insert_subset_insert (subset_iUnion _ _)) ?_
rw [insert_subset_iff, iUnion_subset_iff, and_iff_left (fun i ↦ (hI i).indep.subset_ground)]
exact (hI i).subset_ground hes
theorem Basis.basis_iUnion {ι : Type _} [Nonempty ι] (X : ι → Set α)
(hI : ∀ i, M.Basis I (X i)) : M.Basis I (⋃ i, X i) := by
convert Basis.iUnion_basis_iUnion X (fun _ ↦ I) (fun i ↦ hI i) _ <;> rw [iUnion_const]
exact (hI (Classical.arbitrary ι)).indep
theorem Basis.basis_sUnion {Xs : Set (Set α)} (hne : Xs.Nonempty) (h : ∀ X ∈ Xs, M.Basis I X) :
M.Basis I (⋃₀ Xs) := by
rw [sUnion_eq_iUnion]
have := Iff.mpr nonempty_coe_sort hne
exact Basis.basis_iUnion _ fun X ↦ (h X X.prop)
| Mathlib/Data/Matroid/Basic.lean | 918 | 923 | theorem Indep.basis_setOf_insert_basis (hI : M.Indep I) :
M.Basis I {x | M.Basis I (insert x I)} := by |
refine hI.basis_of_forall_insert (fun e he ↦ (?_ : M.Basis _ _))
(fun e he ↦ ⟨fun hu ↦ he.2 ?_, he.1.subset_ground⟩)
· rw [insert_eq_of_mem he]; exact hI.basis_self
simpa using (hu.eq_of_basis he.1).symm
|
import Mathlib.Algebra.DirectSum.Module
import Mathlib.Analysis.Complex.Basic
import Mathlib.Analysis.Convex.Uniform
import Mathlib.Analysis.NormedSpace.Completion
import Mathlib.Analysis.NormedSpace.BoundedLinearMaps
#align_import analysis.inner_product_space.basic from "leanprover-community/mathlib"@"3f655f5297b030a87d641ad4e825af8d9679eb0b"
noncomputable section
open RCLike Real Filter
open Topology ComplexConjugate
open LinearMap (BilinForm)
variable {𝕜 E F : Type*} [RCLike 𝕜]
class Inner (𝕜 E : Type*) where
inner : E → E → 𝕜
#align has_inner Inner
export Inner (inner)
notation3:max "⟪" x ", " y "⟫_" 𝕜:max => @inner 𝕜 _ _ x y
class InnerProductSpace (𝕜 : Type*) (E : Type*) [RCLike 𝕜] [NormedAddCommGroup E] extends
NormedSpace 𝕜 E, Inner 𝕜 E where
norm_sq_eq_inner : ∀ x : E, ‖x‖ ^ 2 = re (inner x x)
conj_symm : ∀ x y, conj (inner y x) = inner x y
add_left : ∀ x y z, inner (x + y) z = inner x z + inner y z
smul_left : ∀ x y r, inner (r • x) y = conj r * inner x y
#align inner_product_space InnerProductSpace
-- @[nolint HasNonemptyInstance] porting note: I don't think we have this linter anymore
structure InnerProductSpace.Core (𝕜 : Type*) (F : Type*) [RCLike 𝕜] [AddCommGroup F]
[Module 𝕜 F] extends Inner 𝕜 F where
conj_symm : ∀ x y, conj (inner y x) = inner x y
nonneg_re : ∀ x, 0 ≤ re (inner x x)
definite : ∀ x, inner x x = 0 → x = 0
add_left : ∀ x y z, inner (x + y) z = inner x z + inner y z
smul_left : ∀ x y r, inner (r • x) y = conj r * inner x y
#align inner_product_space.core InnerProductSpace.Core
attribute [class] InnerProductSpace.Core
def InnerProductSpace.toCore [NormedAddCommGroup E] [c : InnerProductSpace 𝕜 E] :
InnerProductSpace.Core 𝕜 E :=
{ c with
nonneg_re := fun x => by
rw [← InnerProductSpace.norm_sq_eq_inner]
apply sq_nonneg
definite := fun x hx =>
norm_eq_zero.1 <| pow_eq_zero (n := 2) <| by
rw [InnerProductSpace.norm_sq_eq_inner (𝕜 := 𝕜) x, hx, map_zero] }
#align inner_product_space.to_core InnerProductSpace.toCore
namespace InnerProductSpace.Core
variable [AddCommGroup F] [Module 𝕜 F] [c : InnerProductSpace.Core 𝕜 F]
local notation "⟪" x ", " y "⟫" => @inner 𝕜 F _ x y
local notation "normSqK" => @RCLike.normSq 𝕜 _
local notation "reK" => @RCLike.re 𝕜 _
local notation "ext_iff" => @RCLike.ext_iff 𝕜 _
local postfix:90 "†" => starRingEnd _
def toInner' : Inner 𝕜 F :=
c.toInner
#align inner_product_space.core.to_has_inner' InnerProductSpace.Core.toInner'
attribute [local instance] toInner'
def normSq (x : F) :=
reK ⟪x, x⟫
#align inner_product_space.core.norm_sq InnerProductSpace.Core.normSq
local notation "normSqF" => @normSq 𝕜 F _ _ _ _
theorem inner_conj_symm (x y : F) : ⟪y, x⟫† = ⟪x, y⟫ :=
c.conj_symm x y
#align inner_product_space.core.inner_conj_symm InnerProductSpace.Core.inner_conj_symm
theorem inner_self_nonneg {x : F} : 0 ≤ re ⟪x, x⟫ :=
c.nonneg_re _
#align inner_product_space.core.inner_self_nonneg InnerProductSpace.Core.inner_self_nonneg
theorem inner_self_im (x : F) : im ⟪x, x⟫ = 0 := by
rw [← @ofReal_inj 𝕜, im_eq_conj_sub]
simp [inner_conj_symm]
#align inner_product_space.core.inner_self_im InnerProductSpace.Core.inner_self_im
theorem inner_add_left (x y z : F) : ⟪x + y, z⟫ = ⟪x, z⟫ + ⟪y, z⟫ :=
c.add_left _ _ _
#align inner_product_space.core.inner_add_left InnerProductSpace.Core.inner_add_left
theorem inner_add_right (x y z : F) : ⟪x, y + z⟫ = ⟪x, y⟫ + ⟪x, z⟫ := by
rw [← inner_conj_symm, inner_add_left, RingHom.map_add]; simp only [inner_conj_symm]
#align inner_product_space.core.inner_add_right InnerProductSpace.Core.inner_add_right
theorem ofReal_normSq_eq_inner_self (x : F) : (normSqF x : 𝕜) = ⟪x, x⟫ := by
rw [ext_iff]
exact ⟨by simp only [ofReal_re]; rfl, by simp only [inner_self_im, ofReal_im]⟩
#align inner_product_space.core.coe_norm_sq_eq_inner_self InnerProductSpace.Core.ofReal_normSq_eq_inner_self
theorem inner_re_symm (x y : F) : re ⟪x, y⟫ = re ⟪y, x⟫ := by rw [← inner_conj_symm, conj_re]
#align inner_product_space.core.inner_re_symm InnerProductSpace.Core.inner_re_symm
theorem inner_im_symm (x y : F) : im ⟪x, y⟫ = -im ⟪y, x⟫ := by rw [← inner_conj_symm, conj_im]
#align inner_product_space.core.inner_im_symm InnerProductSpace.Core.inner_im_symm
theorem inner_smul_left (x y : F) {r : 𝕜} : ⟪r • x, y⟫ = r† * ⟪x, y⟫ :=
c.smul_left _ _ _
#align inner_product_space.core.inner_smul_left InnerProductSpace.Core.inner_smul_left
theorem inner_smul_right (x y : F) {r : 𝕜} : ⟪x, r • y⟫ = r * ⟪x, y⟫ := by
rw [← inner_conj_symm, inner_smul_left];
simp only [conj_conj, inner_conj_symm, RingHom.map_mul]
#align inner_product_space.core.inner_smul_right InnerProductSpace.Core.inner_smul_right
theorem inner_zero_left (x : F) : ⟪0, x⟫ = 0 := by
rw [← zero_smul 𝕜 (0 : F), inner_smul_left];
simp only [zero_mul, RingHom.map_zero]
#align inner_product_space.core.inner_zero_left InnerProductSpace.Core.inner_zero_left
theorem inner_zero_right (x : F) : ⟪x, 0⟫ = 0 := by
rw [← inner_conj_symm, inner_zero_left]; simp only [RingHom.map_zero]
#align inner_product_space.core.inner_zero_right InnerProductSpace.Core.inner_zero_right
theorem inner_self_eq_zero {x : F} : ⟪x, x⟫ = 0 ↔ x = 0 :=
⟨c.definite _, by
rintro rfl
exact inner_zero_left _⟩
#align inner_product_space.core.inner_self_eq_zero InnerProductSpace.Core.inner_self_eq_zero
theorem normSq_eq_zero {x : F} : normSqF x = 0 ↔ x = 0 :=
Iff.trans
(by simp only [normSq, ext_iff, map_zero, inner_self_im, eq_self_iff_true, and_true_iff])
(@inner_self_eq_zero 𝕜 _ _ _ _ _ x)
#align inner_product_space.core.norm_sq_eq_zero InnerProductSpace.Core.normSq_eq_zero
theorem inner_self_ne_zero {x : F} : ⟪x, x⟫ ≠ 0 ↔ x ≠ 0 :=
inner_self_eq_zero.not
#align inner_product_space.core.inner_self_ne_zero InnerProductSpace.Core.inner_self_ne_zero
theorem inner_self_ofReal_re (x : F) : (re ⟪x, x⟫ : 𝕜) = ⟪x, x⟫ := by
norm_num [ext_iff, inner_self_im]
set_option linter.uppercaseLean3 false in
#align inner_product_space.core.inner_self_re_to_K InnerProductSpace.Core.inner_self_ofReal_re
theorem norm_inner_symm (x y : F) : ‖⟪x, y⟫‖ = ‖⟪y, x⟫‖ := by rw [← inner_conj_symm, norm_conj]
#align inner_product_space.core.norm_inner_symm InnerProductSpace.Core.norm_inner_symm
theorem inner_neg_left (x y : F) : ⟪-x, y⟫ = -⟪x, y⟫ := by
rw [← neg_one_smul 𝕜 x, inner_smul_left]
simp
#align inner_product_space.core.inner_neg_left InnerProductSpace.Core.inner_neg_left
theorem inner_neg_right (x y : F) : ⟪x, -y⟫ = -⟪x, y⟫ := by
rw [← inner_conj_symm, inner_neg_left]; simp only [RingHom.map_neg, inner_conj_symm]
#align inner_product_space.core.inner_neg_right InnerProductSpace.Core.inner_neg_right
theorem inner_sub_left (x y z : F) : ⟪x - y, z⟫ = ⟪x, z⟫ - ⟪y, z⟫ := by
simp [sub_eq_add_neg, inner_add_left, inner_neg_left]
#align inner_product_space.core.inner_sub_left InnerProductSpace.Core.inner_sub_left
| Mathlib/Analysis/InnerProductSpace/Basic.lean | 290 | 291 | theorem inner_sub_right (x y z : F) : ⟪x, y - z⟫ = ⟪x, y⟫ - ⟪x, z⟫ := by |
simp [sub_eq_add_neg, inner_add_right, inner_neg_right]
|
import Mathlib.Algebra.Order.Ring.Rat
import Mathlib.Tactic.NormNum.Inv
import Mathlib.Tactic.NormNum.Pow
import Mathlib.Util.AtomM
set_option autoImplicit true
namespace Mathlib.Tactic
namespace Ring
open Mathlib.Meta Qq NormNum Lean.Meta AtomM
open Lean (MetaM Expr mkRawNatLit)
def instCommSemiringNat : CommSemiring ℕ := inferInstance
def sℕ : Q(CommSemiring ℕ) := q(instCommSemiringNat)
-- In this file, we would like to use multi-character auto-implicits.
set_option relaxedAutoImplicit true
mutual
inductive ExBase : ∀ {α : Q(Type u)}, Q(CommSemiring $α) → (e : Q($α)) → Type
| atom (id : ℕ) : ExBase sα e
| sum (_ : ExSum sα e) : ExBase sα e
inductive ExProd : ∀ {α : Q(Type u)}, Q(CommSemiring $α) → (e : Q($α)) → Type
| const (value : ℚ) (hyp : Option Expr := none) : ExProd sα e
| mul {α : Q(Type u)} {sα : Q(CommSemiring $α)} {x : Q($α)} {e : Q(ℕ)} {b : Q($α)} :
ExBase sα x → ExProd sℕ e → ExProd sα b → ExProd sα q($x ^ $e * $b)
inductive ExSum : ∀ {α : Q(Type u)}, Q(CommSemiring $α) → (e : Q($α)) → Type
| zero {α : Q(Type u)} {sα : Q(CommSemiring $α)} : ExSum sα q(0 : $α)
| add {α : Q(Type u)} {sα : Q(CommSemiring $α)} {a b : Q($α)} :
ExProd sα a → ExSum sα b → ExSum sα q($a + $b)
end
mutual -- partial only to speed up compilation
partial def ExBase.eq : ExBase sα a → ExBase sα b → Bool
| .atom i, .atom j => i == j
| .sum a, .sum b => a.eq b
| _, _ => false
@[inherit_doc ExBase.eq]
partial def ExProd.eq : ExProd sα a → ExProd sα b → Bool
| .const i _, .const j _ => i == j
| .mul a₁ a₂ a₃, .mul b₁ b₂ b₃ => a₁.eq b₁ && a₂.eq b₂ && a₃.eq b₃
| _, _ => false
@[inherit_doc ExBase.eq]
partial def ExSum.eq : ExSum sα a → ExSum sα b → Bool
| .zero, .zero => true
| .add a₁ a₂, .add b₁ b₂ => a₁.eq b₁ && a₂.eq b₂
| _, _ => false
end
mutual -- partial only to speed up compilation
partial def ExBase.cmp : ExBase sα a → ExBase sα b → Ordering
| .atom i, .atom j => compare i j
| .sum a, .sum b => a.cmp b
| .atom .., .sum .. => .lt
| .sum .., .atom .. => .gt
@[inherit_doc ExBase.cmp]
partial def ExProd.cmp : ExProd sα a → ExProd sα b → Ordering
| .const i _, .const j _ => compare i j
| .mul a₁ a₂ a₃, .mul b₁ b₂ b₃ => (a₁.cmp b₁).then (a₂.cmp b₂) |>.then (a₃.cmp b₃)
| .const _ _, .mul .. => .lt
| .mul .., .const _ _ => .gt
@[inherit_doc ExBase.cmp]
partial def ExSum.cmp : ExSum sα a → ExSum sα b → Ordering
| .zero, .zero => .eq
| .add a₁ a₂, .add b₁ b₂ => (a₁.cmp b₁).then (a₂.cmp b₂)
| .zero, .add .. => .lt
| .add .., .zero => .gt
end
instance : Inhabited (Σ e, (ExBase sα) e) := ⟨default, .atom 0⟩
instance : Inhabited (Σ e, (ExSum sα) e) := ⟨_, .zero⟩
instance : Inhabited (Σ e, (ExProd sα) e) := ⟨default, .const 0 none⟩
mutual
partial def ExBase.cast : ExBase sα a → Σ a, ExBase sβ a
| .atom i => ⟨a, .atom i⟩
| .sum a => let ⟨_, vb⟩ := a.cast; ⟨_, .sum vb⟩
partial def ExProd.cast : ExProd sα a → Σ a, ExProd sβ a
| .const i h => ⟨a, .const i h⟩
| .mul a₁ a₂ a₃ => ⟨_, .mul a₁.cast.2 a₂ a₃.cast.2⟩
partial def ExSum.cast : ExSum sα a → Σ a, ExSum sβ a
| .zero => ⟨_, .zero⟩
| .add a₁ a₂ => ⟨_, .add a₁.cast.2 a₂.cast.2⟩
end
structure Result {α : Q(Type u)} (E : Q($α) → Type) (e : Q($α)) where
expr : Q($α)
val : E expr
proof : Q($e = $expr)
instance [Inhabited (Σ e, E e)] : Inhabited (Result E e) :=
let ⟨e', v⟩ : Σ e, E e := default; ⟨e', v, default⟩
variable {α : Q(Type u)} (sα : Q(CommSemiring $α)) [CommSemiring R]
def ExProd.mkNat (n : ℕ) : (e : Q($α)) × ExProd sα e :=
let lit : Q(ℕ) := mkRawNatLit n
⟨q(($lit).rawCast : $α), .const n none⟩
def ExProd.mkNegNat (_ : Q(Ring $α)) (n : ℕ) : (e : Q($α)) × ExProd sα e :=
let lit : Q(ℕ) := mkRawNatLit n
⟨q((Int.negOfNat $lit).rawCast : $α), .const (-n) none⟩
def ExProd.mkRat (_ : Q(DivisionRing $α)) (q : ℚ) (n : Q(ℤ)) (d : Q(ℕ)) (h : Expr) :
(e : Q($α)) × ExProd sα e :=
⟨q(Rat.rawCast $n $d : $α), .const q h⟩
section
variable {sα}
def ExBase.toProd (va : ExBase sα a) (vb : ExProd sℕ b) :
ExProd sα q($a ^ $b * (nat_lit 1).rawCast) := .mul va vb (.const 1 none)
def ExProd.toSum (v : ExProd sα e) : ExSum sα q($e + 0) := .add v .zero
def ExProd.coeff : ExProd sα e → ℚ
| .const q _ => q
| .mul _ _ v => v.coeff
end
inductive Overlap (e : Q($α)) where
| zero (_ : Q(IsNat $e (nat_lit 0)))
| nonzero (_ : Result (ExProd sα) e)
theorem add_overlap_pf (x : R) (e) (pq_pf : a + b = c) :
x ^ e * a + x ^ e * b = x ^ e * c := by subst_vars; simp [mul_add]
theorem add_overlap_pf_zero (x : R) (e) :
IsNat (a + b) (nat_lit 0) → IsNat (x ^ e * a + x ^ e * b) (nat_lit 0)
| ⟨h⟩ => ⟨by simp [h, ← mul_add]⟩
def evalAddOverlap (va : ExProd sα a) (vb : ExProd sα b) : Option (Overlap sα q($a + $b)) :=
match va, vb with
| .const za ha, .const zb hb => do
let ra := Result.ofRawRat za a ha; let rb := Result.ofRawRat zb b hb
let res ← NormNum.evalAdd.core q($a + $b) q(HAdd.hAdd) a b ra rb
match res with
| .isNat _ (.lit (.natVal 0)) p => pure <| .zero p
| rc =>
let ⟨zc, hc⟩ ← rc.toRatNZ
let ⟨c, pc⟩ := rc.toRawEq
pure <| .nonzero ⟨c, .const zc hc, pc⟩
| .mul (x := a₁) (e := a₂) va₁ va₂ va₃, .mul vb₁ vb₂ vb₃ => do
guard (va₁.eq vb₁ && va₂.eq vb₂)
match ← evalAddOverlap va₃ vb₃ with
| .zero p => pure <| .zero (q(add_overlap_pf_zero $a₁ $a₂ $p) : Expr)
| .nonzero ⟨_, vc, p⟩ =>
pure <| .nonzero ⟨_, .mul va₁ va₂ vc, (q(add_overlap_pf $a₁ $a₂ $p) : Expr)⟩
| _, _ => none
theorem add_pf_zero_add (b : R) : 0 + b = b := by simp
theorem add_pf_add_zero (a : R) : a + 0 = a := by simp
theorem add_pf_add_overlap
(_ : a₁ + b₁ = c₁) (_ : a₂ + b₂ = c₂) : (a₁ + a₂ : R) + (b₁ + b₂) = c₁ + c₂ := by
subst_vars; simp [add_assoc, add_left_comm]
theorem add_pf_add_overlap_zero
(h : IsNat (a₁ + b₁) (nat_lit 0)) (h₄ : a₂ + b₂ = c) : (a₁ + a₂ : R) + (b₁ + b₂) = c := by
subst_vars; rw [add_add_add_comm, h.1, Nat.cast_zero, add_pf_zero_add]
theorem add_pf_add_lt (a₁ : R) (_ : a₂ + b = c) : (a₁ + a₂) + b = a₁ + c := by simp [*, add_assoc]
theorem add_pf_add_gt (b₁ : R) (_ : a + b₂ = c) : a + (b₁ + b₂) = b₁ + c := by
subst_vars; simp [add_left_comm]
partial def evalAdd (va : ExSum sα a) (vb : ExSum sα b) : Result (ExSum sα) q($a + $b) :=
match va, vb with
| .zero, vb => ⟨b, vb, q(add_pf_zero_add $b)⟩
| va, .zero => ⟨a, va, q(add_pf_add_zero $a)⟩
| .add (a := a₁) (b := _a₂) va₁ va₂, .add (a := b₁) (b := _b₂) vb₁ vb₂ =>
match evalAddOverlap sα va₁ vb₁ with
| some (.nonzero ⟨_, vc₁, pc₁⟩) =>
let ⟨_, vc₂, pc₂⟩ := evalAdd va₂ vb₂
⟨_, .add vc₁ vc₂, q(add_pf_add_overlap $pc₁ $pc₂)⟩
| some (.zero pc₁) =>
let ⟨c₂, vc₂, pc₂⟩ := evalAdd va₂ vb₂
⟨c₂, vc₂, q(add_pf_add_overlap_zero $pc₁ $pc₂)⟩
| none =>
if let .lt := va₁.cmp vb₁ then
let ⟨_c, vc, (pc : Q($_a₂ + ($b₁ + $_b₂) = $_c))⟩ := evalAdd va₂ vb
⟨_, .add va₁ vc, q(add_pf_add_lt $a₁ $pc)⟩
else
let ⟨_c, vc, (pc : Q($a₁ + $_a₂ + $_b₂ = $_c))⟩ := evalAdd va vb₂
⟨_, .add vb₁ vc, q(add_pf_add_gt $b₁ $pc)⟩
theorem one_mul (a : R) : (nat_lit 1).rawCast * a = a := by simp [Nat.rawCast]
theorem mul_one (a : R) : a * (nat_lit 1).rawCast = a := by simp [Nat.rawCast]
theorem mul_pf_left (a₁ : R) (a₂) (_ : a₃ * b = c) : (a₁ ^ a₂ * a₃ : R) * b = a₁ ^ a₂ * c := by
subst_vars; rw [mul_assoc]
theorem mul_pf_right (b₁ : R) (b₂) (_ : a * b₃ = c) : a * (b₁ ^ b₂ * b₃) = b₁ ^ b₂ * c := by
subst_vars; rw [mul_left_comm]
theorem mul_pp_pf_overlap (x : R) (_ : ea + eb = e) (_ : a₂ * b₂ = c) :
(x ^ ea * a₂ : R) * (x ^ eb * b₂) = x ^ e * c := by
subst_vars; simp [pow_add, mul_mul_mul_comm]
partial def evalMulProd (va : ExProd sα a) (vb : ExProd sα b) : Result (ExProd sα) q($a * $b) :=
match va, vb with
| .const za ha, .const zb hb =>
if za = 1 then
⟨b, .const zb hb, (q(one_mul $b) : Expr)⟩
else if zb = 1 then
⟨a, .const za ha, (q(mul_one $a) : Expr)⟩
else
let ra := Result.ofRawRat za a ha; let rb := Result.ofRawRat zb b hb
let rc := (NormNum.evalMul.core q($a * $b) q(HMul.hMul) _ _
q(CommSemiring.toSemiring) ra rb).get!
let ⟨zc, hc⟩ := rc.toRatNZ.get!
let ⟨c, pc⟩ := rc.toRawEq
⟨c, .const zc hc, pc⟩
| .mul (x := a₁) (e := a₂) va₁ va₂ va₃, .const _ _ =>
let ⟨_, vc, pc⟩ := evalMulProd va₃ vb
⟨_, .mul va₁ va₂ vc, (q(mul_pf_left $a₁ $a₂ $pc) : Expr)⟩
| .const _ _, .mul (x := b₁) (e := b₂) vb₁ vb₂ vb₃ =>
let ⟨_, vc, pc⟩ := evalMulProd va vb₃
⟨_, .mul vb₁ vb₂ vc, (q(mul_pf_right $b₁ $b₂ $pc) : Expr)⟩
| .mul (x := xa) (e := ea) vxa vea va₂, .mul (x := xb) (e := eb) vxb veb vb₂ => Id.run do
if vxa.eq vxb then
if let some (.nonzero ⟨_, ve, pe⟩) := evalAddOverlap sℕ vea veb then
let ⟨_, vc, pc⟩ := evalMulProd va₂ vb₂
return ⟨_, .mul vxa ve vc, (q(mul_pp_pf_overlap $xa $pe $pc) : Expr)⟩
if let .lt := (vxa.cmp vxb).then (vea.cmp veb) then
let ⟨_, vc, pc⟩ := evalMulProd va₂ vb
⟨_, .mul vxa vea vc, (q(mul_pf_left $xa $ea $pc) : Expr)⟩
else
let ⟨_, vc, pc⟩ := evalMulProd va vb₂
⟨_, .mul vxb veb vc, (q(mul_pf_right $xb $eb $pc) : Expr)⟩
theorem mul_zero (a : R) : a * 0 = 0 := by simp
theorem mul_add (_ : (a : R) * b₁ = c₁) (_ : a * b₂ = c₂) (_ : c₁ + 0 + c₂ = d) :
a * (b₁ + b₂) = d := by subst_vars; simp [_root_.mul_add]
def evalMul₁ (va : ExProd sα a) (vb : ExSum sα b) : Result (ExSum sα) q($a * $b) :=
match vb with
| .zero => ⟨_, .zero, q(mul_zero $a)⟩
| .add vb₁ vb₂ =>
let ⟨_, vc₁, pc₁⟩ := evalMulProd sα va vb₁
let ⟨_, vc₂, pc₂⟩ := evalMul₁ va vb₂
let ⟨_, vd, pd⟩ := evalAdd sα vc₁.toSum vc₂
⟨_, vd, q(mul_add $pc₁ $pc₂ $pd)⟩
theorem zero_mul (b : R) : 0 * b = 0 := by simp
theorem add_mul (_ : (a₁ : R) * b = c₁) (_ : a₂ * b = c₂) (_ : c₁ + c₂ = d) :
(a₁ + a₂) * b = d := by subst_vars; simp [_root_.add_mul]
def evalMul (va : ExSum sα a) (vb : ExSum sα b) : Result (ExSum sα) q($a * $b) :=
match va with
| .zero => ⟨_, .zero, q(zero_mul $b)⟩
| .add va₁ va₂ =>
let ⟨_, vc₁, pc₁⟩ := evalMul₁ sα va₁ vb
let ⟨_, vc₂, pc₂⟩ := evalMul va₂ vb
let ⟨_, vd, pd⟩ := evalAdd sα vc₁ vc₂
⟨_, vd, q(add_mul $pc₁ $pc₂ $pd)⟩
theorem natCast_nat (n) : ((Nat.rawCast n : ℕ) : R) = Nat.rawCast n := by simp
theorem natCast_mul (a₂) (_ : ((a₁ : ℕ) : R) = b₁) (_ : ((a₃ : ℕ) : R) = b₃) :
((a₁ ^ a₂ * a₃ : ℕ) : R) = b₁ ^ a₂ * b₃ := by subst_vars; simp
theorem natCast_zero : ((0 : ℕ) : R) = 0 := Nat.cast_zero
| Mathlib/Tactic/Ring/Basic.lean | 458 | 459 | theorem natCast_add (_ : ((a₁ : ℕ) : R) = b₁) (_ : ((a₂ : ℕ) : R) = b₂) :
((a₁ + a₂ : ℕ) : R) = b₁ + b₂ := by | subst_vars; simp
|
import Mathlib.CategoryTheory.Filtered.Final
universe w v v₁ u u₁
open CategoryTheory Functor
namespace CategoryTheory
section WeaklyTerminal
variable (J : Type u) [Category.{v} J]
theorem FinallySmall.exists_small_weakly_terminal_set [FinallySmall.{w} J] :
∃ (s : Set J) (_ : Small.{w} s), ∀ i, ∃ j ∈ s, Nonempty (i ⟶ j) := by
refine ⟨Set.range (fromFinalModel J).obj, inferInstance, fun i => ?_⟩
obtain ⟨f⟩ : Nonempty (StructuredArrow i (fromFinalModel J)) := IsConnected.is_nonempty
exact ⟨(fromFinalModel J).obj f.right, Set.mem_range_self _, ⟨f.hom⟩⟩
variable {J} in
theorem finallySmall_of_small_weakly_terminal_set [IsFilteredOrEmpty J] (s : Set J) [Small.{v} s]
(hs : ∀ i, ∃ j ∈ s, Nonempty (i ⟶ j)) : FinallySmall.{v} J := by
suffices Functor.Final (fullSubcategoryInclusion (· ∈ s)) from
finallySmall_of_final_of_essentiallySmall (fullSubcategoryInclusion (· ∈ s))
refine Functor.final_of_exists_of_isFiltered_of_fullyFaithful _ (fun i => ?_)
obtain ⟨j, hj₁, hj₂⟩ := hs i
exact ⟨⟨j, hj₁⟩, hj₂⟩
| Mathlib/CategoryTheory/Limits/FinallySmall.lean | 147 | 151 | theorem finallySmall_iff_exists_small_weakly_terminal_set [IsFilteredOrEmpty J] :
FinallySmall.{v} J ↔ ∃ (s : Set J) (_ : Small.{v} s), ∀ i, ∃ j ∈ s, Nonempty (i ⟶ j) := by |
refine ⟨fun _ => FinallySmall.exists_small_weakly_terminal_set _, fun h => ?_⟩
rcases h with ⟨s, hs, hs'⟩
exact finallySmall_of_small_weakly_terminal_set s hs'
|
import Mathlib.Algebra.Group.Units.Equiv
import Mathlib.CategoryTheory.Endomorphism
#align_import category_theory.conj from "leanprover-community/mathlib"@"32253a1a1071173b33dc7d6a218cf722c6feb514"
universe v u
namespace CategoryTheory
namespace Functor
universe v₁ u₁
variable {C : Type u} [Category.{v} C] {D : Type u₁} [Category.{v₁} D] (F : C ⥤ D)
| Mathlib/CategoryTheory/Conj.lean | 194 | 195 | theorem map_homCongr {X Y X₁ Y₁ : C} (α : X ≅ X₁) (β : Y ≅ Y₁) (f : X ⟶ Y) :
F.map (Iso.homCongr α β f) = Iso.homCongr (F.mapIso α) (F.mapIso β) (F.map f) := by | simp
|
import Mathlib.Algebra.Category.ModuleCat.Free
import Mathlib.Topology.Category.Profinite.CofilteredLimit
import Mathlib.Topology.Category.Profinite.Product
import Mathlib.Topology.LocallyConstant.Algebra
import Mathlib.Init.Data.Bool.Lemmas
universe u
namespace Profinite
namespace NobelingProof
variable {I : Type u} [LinearOrder I] [IsWellOrder I (·<·)] (C : Set (I → Bool))
open Profinite ContinuousMap CategoryTheory Limits Opposite Submodule
def GoodProducts := {l : Products I | l.isGood C}
| Mathlib/Topology/Category/Profinite/Nobeling.lean | 429 | 447 | theorem GoodProducts.span_iff_products : ⊤ ≤ span ℤ (Set.range (eval C)) ↔
⊤ ≤ span ℤ (Set.range (Products.eval C)) := by |
refine ⟨fun h ↦ le_trans h (span_mono (fun a ⟨b, hb⟩ ↦ ⟨b.val, hb⟩)), fun h ↦ le_trans h ?_⟩
rw [span_le]
rintro f ⟨l, rfl⟩
let L : Products I → Prop := fun m ↦ m.eval C ∈ span ℤ (Set.range (GoodProducts.eval C))
suffices L l by assumption
apply IsWellFounded.induction (·<· : Products I → Products I → Prop)
intro l h
dsimp
by_cases hl : l.isGood C
· apply subset_span
exact ⟨⟨l, hl⟩, rfl⟩
· simp only [Products.isGood, not_not] at hl
suffices Products.eval C '' {m | m < l} ⊆ span ℤ (Set.range (GoodProducts.eval C)) by
rw [← span_le] at this
exact this hl
rintro a ⟨m, hm, rfl⟩
exact h m hm
|
import Mathlib.CategoryTheory.Limits.HasLimits
import Mathlib.CategoryTheory.Thin
#align_import category_theory.limits.shapes.wide_pullbacks from "leanprover-community/mathlib"@"f187f1074fa1857c94589cc653c786cadc4c35ff"
universe w w' v u
open CategoryTheory CategoryTheory.Limits Opposite
namespace CategoryTheory.Limits
variable (J : Type w)
def WidePullbackShape := Option J
#align category_theory.limits.wide_pullback_shape CategoryTheory.Limits.WidePullbackShape
-- Porting note: strangely this could be synthesized
instance : Inhabited (WidePullbackShape J) where
default := none
def WidePushoutShape := Option J
#align category_theory.limits.wide_pushout_shape CategoryTheory.Limits.WidePushoutShape
instance : Inhabited (WidePushoutShape J) where
default := none
namespace WidePushout
variable {C : Type u} [Category.{v} C] {B : C} {objs : J → C} (arrows : ∀ j : J, B ⟶ objs j)
variable [HasWidePushout B objs arrows]
noncomputable abbrev ι (j : J) : objs j ⟶ widePushout _ _ arrows :=
colimit.ι (WidePushoutShape.wideSpan _ _ _) (Option.some j)
#align category_theory.limits.wide_pushout.ι CategoryTheory.Limits.WidePushout.ι
noncomputable abbrev head : B ⟶ widePushout B objs arrows :=
colimit.ι (WidePushoutShape.wideSpan _ _ _) Option.none
#align category_theory.limits.wide_pushout.head CategoryTheory.Limits.WidePushout.head
@[reassoc (attr := simp)]
theorem arrow_ι (j : J) : arrows j ≫ ι arrows j = head arrows := by
apply colimit.w (WidePushoutShape.wideSpan _ _ _) (WidePushoutShape.Hom.init j)
#align category_theory.limits.wide_pushout.arrow_ι CategoryTheory.Limits.WidePushout.arrow_ι
-- Porting note: this can simplify itself
attribute [nolint simpNF] WidePushout.arrow_ι WidePushout.arrow_ι_assoc
variable {arrows}
noncomputable abbrev desc {X : C} (f : B ⟶ X) (fs : ∀ j : J, objs j ⟶ X)
(w : ∀ j, arrows j ≫ fs j = f) : widePushout _ _ arrows ⟶ X :=
colimit.desc (WidePushoutShape.wideSpan B objs arrows) (WidePushoutShape.mkCocone f fs <| w)
#align category_theory.limits.wide_pushout.desc CategoryTheory.Limits.WidePushout.desc
variable (arrows)
variable {X : C} (f : B ⟶ X) (fs : ∀ j : J, objs j ⟶ X) (w : ∀ j, arrows j ≫ fs j = f)
-- Porting note (#10618): simp can prove this so removed simp attribute
@[reassoc]
theorem ι_desc (j : J) : ι arrows j ≫ desc f fs w = fs _ := by
simp only [colimit.ι_desc, WidePushoutShape.mkCocone_pt, WidePushoutShape.mkCocone_ι_app]
#align category_theory.limits.wide_pushout.ι_desc CategoryTheory.Limits.WidePushout.ι_desc
-- Porting note (#10618): simp can prove this so removed simp attribute
@[reassoc]
theorem head_desc : head arrows ≫ desc f fs w = f := by
simp only [colimit.ι_desc, WidePushoutShape.mkCocone_pt, WidePushoutShape.mkCocone_ι_app]
#align category_theory.limits.wide_pushout.head_desc CategoryTheory.Limits.WidePushout.head_desc
theorem eq_desc_of_comp_eq (g : widePushout _ _ arrows ⟶ X) :
(∀ j : J, ι arrows j ≫ g = fs j) → head arrows ≫ g = f → g = desc f fs w := by
intro h1 h2
apply
(colimit.isColimit (WidePushoutShape.wideSpan B objs arrows)).uniq
(WidePushoutShape.mkCocone f fs <| w)
rintro (_ | _)
· apply h2
· apply h1
#align category_theory.limits.wide_pushout.eq_desc_of_comp_eq CategoryTheory.Limits.WidePushout.eq_desc_of_comp_eq
theorem hom_eq_desc (g : widePushout _ _ arrows ⟶ X) :
g =
desc (head arrows ≫ g) (fun j => ι arrows j ≫ g) fun j => by
rw [← Category.assoc]
simp := by
apply eq_desc_of_comp_eq
· aesop_cat
· rfl -- Porting note: another missing rfl
#align category_theory.limits.wide_pushout.hom_eq_desc CategoryTheory.Limits.WidePushout.hom_eq_desc
@[ext 1100]
| Mathlib/CategoryTheory/Limits/Shapes/WidePullbacks.lean | 466 | 472 | theorem hom_ext (g1 g2 : widePushout _ _ arrows ⟶ X) : (∀ j : J,
ι arrows j ≫ g1 = ι arrows j ≫ g2) → head arrows ≫ g1 = head arrows ≫ g2 → g1 = g2 := by |
intro h1 h2
apply colimit.hom_ext
rintro (_ | _)
· apply h2
· apply h1
|
import Mathlib.Algebra.Polynomial.Degree.Definitions
import Mathlib.Algebra.Polynomial.Induction
#align_import data.polynomial.eval from "leanprover-community/mathlib"@"728baa2f54e6062c5879a3e397ac6bac323e506f"
set_option linter.uppercaseLean3 false
noncomputable section
open Finset AddMonoidAlgebra
open Polynomial
namespace Polynomial
universe u v w y
variable {R : Type u} {S : Type v} {T : Type w} {ι : Type y} {a b : R} {m n : ℕ}
section Semiring
variable [Semiring R] {p q r : R[X]}
section
variable [Semiring S]
variable (f : R →+* S) (x : S)
irreducible_def eval₂ (p : R[X]) : S :=
p.sum fun e a => f a * x ^ e
#align polynomial.eval₂ Polynomial.eval₂
theorem eval₂_eq_sum {f : R →+* S} {x : S} : p.eval₂ f x = p.sum fun e a => f a * x ^ e := by
rw [eval₂_def]
#align polynomial.eval₂_eq_sum Polynomial.eval₂_eq_sum
theorem eval₂_congr {R S : Type*} [Semiring R] [Semiring S] {f g : R →+* S} {s t : S}
{φ ψ : R[X]} : f = g → s = t → φ = ψ → eval₂ f s φ = eval₂ g t ψ := by
rintro rfl rfl rfl; rfl
#align polynomial.eval₂_congr Polynomial.eval₂_congr
@[simp]
theorem eval₂_at_zero : p.eval₂ f 0 = f (coeff p 0) := by
simp (config := { contextual := true }) only [eval₂_eq_sum, zero_pow_eq, mul_ite, mul_zero,
mul_one, sum, Classical.not_not, mem_support_iff, sum_ite_eq', ite_eq_left_iff,
RingHom.map_zero, imp_true_iff, eq_self_iff_true]
#align polynomial.eval₂_at_zero Polynomial.eval₂_at_zero
@[simp]
theorem eval₂_zero : (0 : R[X]).eval₂ f x = 0 := by simp [eval₂_eq_sum]
#align polynomial.eval₂_zero Polynomial.eval₂_zero
@[simp]
theorem eval₂_C : (C a).eval₂ f x = f a := by simp [eval₂_eq_sum]
#align polynomial.eval₂_C Polynomial.eval₂_C
@[simp]
theorem eval₂_X : X.eval₂ f x = x := by simp [eval₂_eq_sum]
#align polynomial.eval₂_X Polynomial.eval₂_X
@[simp]
theorem eval₂_monomial {n : ℕ} {r : R} : (monomial n r).eval₂ f x = f r * x ^ n := by
simp [eval₂_eq_sum]
#align polynomial.eval₂_monomial Polynomial.eval₂_monomial
@[simp]
theorem eval₂_X_pow {n : ℕ} : (X ^ n).eval₂ f x = x ^ n := by
rw [X_pow_eq_monomial]
convert eval₂_monomial f x (n := n) (r := 1)
simp
#align polynomial.eval₂_X_pow Polynomial.eval₂_X_pow
@[simp]
theorem eval₂_add : (p + q).eval₂ f x = p.eval₂ f x + q.eval₂ f x := by
simp only [eval₂_eq_sum]
apply sum_add_index <;> simp [add_mul]
#align polynomial.eval₂_add Polynomial.eval₂_add
@[simp]
theorem eval₂_one : (1 : R[X]).eval₂ f x = 1 := by rw [← C_1, eval₂_C, f.map_one]
#align polynomial.eval₂_one Polynomial.eval₂_one
set_option linter.deprecated false in
@[simp]
theorem eval₂_bit0 : (bit0 p).eval₂ f x = bit0 (p.eval₂ f x) := by rw [bit0, eval₂_add, bit0]
#align polynomial.eval₂_bit0 Polynomial.eval₂_bit0
set_option linter.deprecated false in
@[simp]
theorem eval₂_bit1 : (bit1 p).eval₂ f x = bit1 (p.eval₂ f x) := by
rw [bit1, eval₂_add, eval₂_bit0, eval₂_one, bit1]
#align polynomial.eval₂_bit1 Polynomial.eval₂_bit1
@[simp]
theorem eval₂_smul (g : R →+* S) (p : R[X]) (x : S) {s : R} :
eval₂ g x (s • p) = g s * eval₂ g x p := by
have A : p.natDegree < p.natDegree.succ := Nat.lt_succ_self _
have B : (s • p).natDegree < p.natDegree.succ := (natDegree_smul_le _ _).trans_lt A
rw [eval₂_eq_sum, eval₂_eq_sum, sum_over_range' _ _ _ A, sum_over_range' _ _ _ B] <;>
simp [mul_sum, mul_assoc]
#align polynomial.eval₂_smul Polynomial.eval₂_smul
@[simp]
theorem eval₂_C_X : eval₂ C X p = p :=
Polynomial.induction_on' p (fun p q hp hq => by simp [hp, hq]) fun n x => by
rw [eval₂_monomial, ← smul_X_eq_monomial, C_mul']
#align polynomial.eval₂_C_X Polynomial.eval₂_C_X
@[simps]
def eval₂AddMonoidHom : R[X] →+ S where
toFun := eval₂ f x
map_zero' := eval₂_zero _ _
map_add' _ _ := eval₂_add _ _
#align polynomial.eval₂_add_monoid_hom Polynomial.eval₂AddMonoidHom
#align polynomial.eval₂_add_monoid_hom_apply Polynomial.eval₂AddMonoidHom_apply
@[simp]
theorem eval₂_natCast (n : ℕ) : (n : R[X]).eval₂ f x = n := by
induction' n with n ih
-- Porting note: `Nat.zero_eq` is required.
· simp only [eval₂_zero, Nat.cast_zero, Nat.zero_eq]
· rw [n.cast_succ, eval₂_add, ih, eval₂_one, n.cast_succ]
#align polynomial.eval₂_nat_cast Polynomial.eval₂_natCast
@[deprecated (since := "2024-04-17")]
alias eval₂_nat_cast := eval₂_natCast
-- See note [no_index around OfNat.ofNat]
@[simp]
lemma eval₂_ofNat {S : Type*} [Semiring S] (n : ℕ) [n.AtLeastTwo] (f : R →+* S) (a : S) :
(no_index (OfNat.ofNat n : R[X])).eval₂ f a = OfNat.ofNat n := by
simp [OfNat.ofNat]
variable [Semiring T]
theorem eval₂_sum (p : T[X]) (g : ℕ → T → R[X]) (x : S) :
(p.sum g).eval₂ f x = p.sum fun n a => (g n a).eval₂ f x := by
let T : R[X] →+ S :=
{ toFun := eval₂ f x
map_zero' := eval₂_zero _ _
map_add' := fun p q => eval₂_add _ _ }
have A : ∀ y, eval₂ f x y = T y := fun y => rfl
simp only [A]
rw [sum, map_sum, sum]
#align polynomial.eval₂_sum Polynomial.eval₂_sum
theorem eval₂_list_sum (l : List R[X]) (x : S) : eval₂ f x l.sum = (l.map (eval₂ f x)).sum :=
map_list_sum (eval₂AddMonoidHom f x) l
#align polynomial.eval₂_list_sum Polynomial.eval₂_list_sum
theorem eval₂_multiset_sum (s : Multiset R[X]) (x : S) :
eval₂ f x s.sum = (s.map (eval₂ f x)).sum :=
map_multiset_sum (eval₂AddMonoidHom f x) s
#align polynomial.eval₂_multiset_sum Polynomial.eval₂_multiset_sum
theorem eval₂_finset_sum (s : Finset ι) (g : ι → R[X]) (x : S) :
(∑ i ∈ s, g i).eval₂ f x = ∑ i ∈ s, (g i).eval₂ f x :=
map_sum (eval₂AddMonoidHom f x) _ _
#align polynomial.eval₂_finset_sum Polynomial.eval₂_finset_sum
theorem eval₂_ofFinsupp {f : R →+* S} {x : S} {p : R[ℕ]} :
eval₂ f x (⟨p⟩ : R[X]) = liftNC (↑f) (powersHom S x) p := by
simp only [eval₂_eq_sum, sum, toFinsupp_sum, support, coeff]
rfl
#align polynomial.eval₂_of_finsupp Polynomial.eval₂_ofFinsupp
theorem eval₂_mul_noncomm (hf : ∀ k, Commute (f <| q.coeff k) x) :
eval₂ f x (p * q) = eval₂ f x p * eval₂ f x q := by
rcases p with ⟨p⟩; rcases q with ⟨q⟩
simp only [coeff] at hf
simp only [← ofFinsupp_mul, eval₂_ofFinsupp]
exact liftNC_mul _ _ p q fun {k n} _hn => (hf k).pow_right n
#align polynomial.eval₂_mul_noncomm Polynomial.eval₂_mul_noncomm
@[simp]
theorem eval₂_mul_X : eval₂ f x (p * X) = eval₂ f x p * x := by
refine _root_.trans (eval₂_mul_noncomm _ _ fun k => ?_) (by rw [eval₂_X])
rcases em (k = 1) with (rfl | hk)
· simp
· simp [coeff_X_of_ne_one hk]
#align polynomial.eval₂_mul_X Polynomial.eval₂_mul_X
@[simp]
theorem eval₂_X_mul : eval₂ f x (X * p) = eval₂ f x p * x := by rw [X_mul, eval₂_mul_X]
#align polynomial.eval₂_X_mul Polynomial.eval₂_X_mul
theorem eval₂_mul_C' (h : Commute (f a) x) : eval₂ f x (p * C a) = eval₂ f x p * f a := by
rw [eval₂_mul_noncomm, eval₂_C]
intro k
by_cases hk : k = 0
· simp only [hk, h, coeff_C_zero, coeff_C_ne_zero]
· simp only [coeff_C_ne_zero hk, RingHom.map_zero, Commute.zero_left]
#align polynomial.eval₂_mul_C' Polynomial.eval₂_mul_C'
theorem eval₂_list_prod_noncomm (ps : List R[X])
(hf : ∀ p ∈ ps, ∀ (k), Commute (f <| coeff p k) x) :
eval₂ f x ps.prod = (ps.map (Polynomial.eval₂ f x)).prod := by
induction' ps using List.reverseRecOn with ps p ihp
· simp
· simp only [List.forall_mem_append, List.forall_mem_singleton] at hf
simp [eval₂_mul_noncomm _ _ hf.2, ihp hf.1]
#align polynomial.eval₂_list_prod_noncomm Polynomial.eval₂_list_prod_noncomm
@[simps]
def eval₂RingHom' (f : R →+* S) (x : S) (hf : ∀ a, Commute (f a) x) : R[X] →+* S where
toFun := eval₂ f x
map_add' _ _ := eval₂_add _ _
map_zero' := eval₂_zero _ _
map_mul' _p q := eval₂_mul_noncomm f x fun k => hf <| coeff q k
map_one' := eval₂_one _ _
#align polynomial.eval₂_ring_hom' Polynomial.eval₂RingHom'
end
section Comp
def comp (p q : R[X]) : R[X] :=
p.eval₂ C q
#align polynomial.comp Polynomial.comp
theorem comp_eq_sum_left : p.comp q = p.sum fun e a => C a * q ^ e := by rw [comp, eval₂_eq_sum]
#align polynomial.comp_eq_sum_left Polynomial.comp_eq_sum_left
@[simp]
theorem comp_X : p.comp X = p := by
simp only [comp, eval₂_def, C_mul_X_pow_eq_monomial]
exact sum_monomial_eq _
#align polynomial.comp_X Polynomial.comp_X
@[simp]
theorem X_comp : X.comp p = p :=
eval₂_X _ _
#align polynomial.X_comp Polynomial.X_comp
@[simp]
theorem comp_C : p.comp (C a) = C (p.eval a) := by simp [comp, map_sum (C : R →+* _)]
#align polynomial.comp_C Polynomial.comp_C
@[simp]
theorem C_comp : (C a).comp p = C a :=
eval₂_C _ _
#align polynomial.C_comp Polynomial.C_comp
@[simp]
theorem natCast_comp {n : ℕ} : (n : R[X]).comp p = n := by rw [← C_eq_natCast, C_comp]
#align polynomial.nat_cast_comp Polynomial.natCast_comp
@[deprecated (since := "2024-04-17")]
alias nat_cast_comp := natCast_comp
-- Porting note (#10756): new theorem
@[simp]
theorem ofNat_comp (n : ℕ) [n.AtLeastTwo] : (no_index (OfNat.ofNat n) : R[X]).comp p = n :=
natCast_comp
@[simp]
theorem comp_zero : p.comp (0 : R[X]) = C (p.eval 0) := by rw [← C_0, comp_C]
#align polynomial.comp_zero Polynomial.comp_zero
@[simp]
theorem zero_comp : comp (0 : R[X]) p = 0 := by rw [← C_0, C_comp]
#align polynomial.zero_comp Polynomial.zero_comp
@[simp]
theorem comp_one : p.comp 1 = C (p.eval 1) := by rw [← C_1, comp_C]
#align polynomial.comp_one Polynomial.comp_one
@[simp]
| Mathlib/Algebra/Polynomial/Eval.lean | 603 | 603 | theorem one_comp : comp (1 : R[X]) p = 1 := by | rw [← C_1, C_comp]
|
import Mathlib.Analysis.NormedSpace.AddTorsor
import Mathlib.LinearAlgebra.AffineSpace.Ordered
import Mathlib.Topology.ContinuousFunction.Basic
import Mathlib.Topology.GDelta
import Mathlib.Analysis.NormedSpace.FunctionSeries
import Mathlib.Analysis.SpecificLimits.Basic
#align_import topology.urysohns_lemma from "leanprover-community/mathlib"@"f2ce6086713c78a7f880485f7917ea547a215982"
variable {X : Type*} [TopologicalSpace X]
open Set Filter TopologicalSpace Topology Filter
open scoped Pointwise
namespace Urysohns
set_option linter.uppercaseLean3 false
structure CU {X : Type*} [TopologicalSpace X] (P : Set X → Prop) where
protected C : Set X
protected U : Set X
protected P_C : P C
protected closed_C : IsClosed C
protected open_U : IsOpen U
protected subset : C ⊆ U
protected hP : ∀ {c u : Set X}, IsClosed c → P c → IsOpen u → c ⊆ u →
∃ v, IsOpen v ∧ c ⊆ v ∧ closure v ⊆ u ∧ P (closure v)
#align urysohns.CU Urysohns.CU
theorem exists_continuous_zero_one_of_isClosed [NormalSpace X]
{s t : Set X} (hs : IsClosed s) (ht : IsClosed t)
(hd : Disjoint s t) : ∃ f : C(X, ℝ), EqOn f 0 s ∧ EqOn f 1 t ∧ ∀ x, f x ∈ Icc (0 : ℝ) 1 := by
-- The actual proof is in the code above. Here we just repack it into the expected format.
let P : Set X → Prop := fun _ ↦ True
set c : Urysohns.CU P :=
{ C := s
U := tᶜ
P_C := trivial
closed_C := hs
open_U := ht.isOpen_compl
subset := disjoint_left.1 hd
hP := by
rintro c u c_closed - u_open cu
rcases normal_exists_closure_subset c_closed u_open cu with ⟨v, v_open, cv, hv⟩
exact ⟨v, v_open, cv, hv, trivial⟩ }
exact ⟨⟨c.lim, c.continuous_lim⟩, c.lim_of_mem_C, fun x hx => c.lim_of_nmem_U _ fun h => h hx,
c.lim_mem_Icc⟩
#align exists_continuous_zero_one_of_closed exists_continuous_zero_one_of_isClosed
| Mathlib/Topology/UrysohnsLemma.lean | 355 | 376 | theorem exists_continuous_zero_one_of_isCompact [RegularSpace X] [LocallyCompactSpace X]
{s t : Set X} (hs : IsCompact s) (ht : IsClosed t) (hd : Disjoint s t) :
∃ f : C(X, ℝ), EqOn f 0 s ∧ EqOn f 1 t ∧ ∀ x, f x ∈ Icc (0 : ℝ) 1 := by |
obtain ⟨k, k_comp, k_closed, sk, kt⟩ : ∃ k, IsCompact k ∧ IsClosed k ∧ s ⊆ interior k ∧ k ⊆ tᶜ :=
exists_compact_closed_between hs ht.isOpen_compl hd.symm.subset_compl_left
let P : Set X → Prop := IsCompact
set c : Urysohns.CU P :=
{ C := k
U := tᶜ
P_C := k_comp
closed_C := k_closed
open_U := ht.isOpen_compl
subset := kt
hP := by
rintro c u - c_comp u_open cu
rcases exists_compact_closed_between c_comp u_open cu with ⟨k, k_comp, k_closed, ck, ku⟩
have A : closure (interior k) ⊆ k :=
(IsClosed.closure_subset_iff k_closed).2 interior_subset
refine ⟨interior k, isOpen_interior, ck, A.trans ku,
k_comp.of_isClosed_subset isClosed_closure A⟩ }
exact ⟨⟨c.lim, c.continuous_lim⟩, fun x hx ↦ c.lim_of_mem_C _ (sk.trans interior_subset hx),
fun x hx => c.lim_of_nmem_U _ fun h => h hx, c.lim_mem_Icc⟩
|
import Mathlib.Analysis.Normed.Group.AddTorsor
import Mathlib.Analysis.InnerProductSpace.Basic
import Mathlib.Tactic.AdaptationNote
#align_import geometry.euclidean.inversion from "leanprover-community/mathlib"@"46b633fd842bef9469441c0209906f6dddd2b4f5"
noncomputable section
open Metric Function AffineMap Set AffineSubspace
open scoped Topology
variable {V P : Type*} [NormedAddCommGroup V] [InnerProductSpace ℝ V] [MetricSpace P]
[NormedAddTorsor V P]
namespace EuclideanGeometry
variable {a b c d x y z : P} {r R : ℝ}
def inversion (c : P) (R : ℝ) (x : P) : P :=
(R / dist x c) ^ 2 • (x -ᵥ c) +ᵥ c
#align euclidean_geometry.inversion EuclideanGeometry.inversion
#adaptation_note
theorem inversion_def :
inversion = fun (c : P) (R : ℝ) (x : P) => (R / dist x c) ^ 2 • (x -ᵥ c) +ᵥ c :=
rfl
theorem inversion_eq_lineMap (c : P) (R : ℝ) (x : P) :
inversion c R x = lineMap c x ((R / dist x c) ^ 2) :=
rfl
theorem inversion_vsub_center (c : P) (R : ℝ) (x : P) :
inversion c R x -ᵥ c = (R / dist x c) ^ 2 • (x -ᵥ c) :=
vadd_vsub _ _
#align euclidean_geometry.inversion_vsub_center EuclideanGeometry.inversion_vsub_center
@[simp]
theorem inversion_self (c : P) (R : ℝ) : inversion c R c = c := by simp [inversion]
#align euclidean_geometry.inversion_self EuclideanGeometry.inversion_self
@[simp]
theorem inversion_zero_radius (c x : P) : inversion c 0 x = c := by simp [inversion]
theorem inversion_mul (c : P) (a R : ℝ) (x : P) :
inversion c (a * R) x = homothety c (a ^ 2) (inversion c R x) := by
simp only [inversion_eq_lineMap, ← homothety_eq_lineMap, ← homothety_mul_apply, mul_div_assoc,
mul_pow]
@[simp]
theorem inversion_dist_center (c x : P) : inversion c (dist x c) x = x := by
rcases eq_or_ne x c with (rfl | hne)
· apply inversion_self
· rw [inversion, div_self, one_pow, one_smul, vsub_vadd]
rwa [dist_ne_zero]
#align euclidean_geometry.inversion_dist_center EuclideanGeometry.inversion_dist_center
@[simp]
theorem inversion_dist_center' (c x : P) : inversion c (dist c x) x = x := by
rw [dist_comm, inversion_dist_center]
theorem inversion_of_mem_sphere (h : x ∈ Metric.sphere c R) : inversion c R x = x :=
h.out ▸ inversion_dist_center c x
#align euclidean_geometry.inversion_of_mem_sphere EuclideanGeometry.inversion_of_mem_sphere
theorem dist_inversion_center (c x : P) (R : ℝ) : dist (inversion c R x) c = R ^ 2 / dist x c := by
rcases eq_or_ne x c with (rfl | hx)
· simp
have : dist x c ≠ 0 := dist_ne_zero.2 hx
field_simp [inversion, norm_smul, abs_div, ← dist_eq_norm_vsub, sq, mul_assoc]
#align euclidean_geometry.dist_inversion_center EuclideanGeometry.dist_inversion_center
theorem dist_center_inversion (c x : P) (R : ℝ) : dist c (inversion c R x) = R ^ 2 / dist c x := by
rw [dist_comm c, dist_comm c, dist_inversion_center]
#align euclidean_geometry.dist_center_inversion EuclideanGeometry.dist_center_inversion
@[simp]
theorem inversion_inversion (c : P) {R : ℝ} (hR : R ≠ 0) (x : P) :
inversion c R (inversion c R x) = x := by
rcases eq_or_ne x c with (rfl | hne)
· rw [inversion_self, inversion_self]
· rw [inversion, dist_inversion_center, inversion_vsub_center, smul_smul, ← mul_pow,
div_mul_div_comm, div_mul_cancel₀ _ (dist_ne_zero.2 hne), ← sq, div_self, one_pow, one_smul,
vsub_vadd]
exact pow_ne_zero _ hR
#align euclidean_geometry.inversion_inversion EuclideanGeometry.inversion_inversion
theorem inversion_involutive (c : P) {R : ℝ} (hR : R ≠ 0) : Involutive (inversion c R) :=
inversion_inversion c hR
#align euclidean_geometry.inversion_involutive EuclideanGeometry.inversion_involutive
theorem inversion_surjective (c : P) {R : ℝ} (hR : R ≠ 0) : Surjective (inversion c R) :=
(inversion_involutive c hR).surjective
#align euclidean_geometry.inversion_surjective EuclideanGeometry.inversion_surjective
theorem inversion_injective (c : P) {R : ℝ} (hR : R ≠ 0) : Injective (inversion c R) :=
(inversion_involutive c hR).injective
#align euclidean_geometry.inversion_injective EuclideanGeometry.inversion_injective
theorem inversion_bijective (c : P) {R : ℝ} (hR : R ≠ 0) : Bijective (inversion c R) :=
(inversion_involutive c hR).bijective
#align euclidean_geometry.inversion_bijective EuclideanGeometry.inversion_bijective
theorem inversion_eq_center (hR : R ≠ 0) : inversion c R x = c ↔ x = c :=
(inversion_injective c hR).eq_iff' <| inversion_self _ _
@[simp]
theorem inversion_eq_center' : inversion c R x = c ↔ x = c ∨ R = 0 := by
by_cases hR : R = 0 <;> simp [inversion_eq_center, hR]
theorem center_eq_inversion (hR : R ≠ 0) : c = inversion c R x ↔ x = c :=
eq_comm.trans (inversion_eq_center hR)
@[simp]
theorem center_eq_inversion' : c = inversion c R x ↔ x = c ∨ R = 0 :=
eq_comm.trans inversion_eq_center'
| Mathlib/Geometry/Euclidean/Inversion/Basic.lean | 162 | 167 | theorem dist_inversion_inversion (hx : x ≠ c) (hy : y ≠ c) (R : ℝ) :
dist (inversion c R x) (inversion c R y) = R ^ 2 / (dist x c * dist y c) * dist x y := by |
dsimp only [inversion]
simp_rw [dist_vadd_cancel_right, dist_eq_norm_vsub V _ c]
simpa only [dist_vsub_cancel_right] using
dist_div_norm_sq_smul (vsub_ne_zero.2 hx) (vsub_ne_zero.2 hy) R
|
import Mathlib.MeasureTheory.Covering.VitaliFamily
import Mathlib.MeasureTheory.Measure.Regular
import Mathlib.MeasureTheory.Function.AEMeasurableOrder
import Mathlib.MeasureTheory.Integral.Lebesgue
import Mathlib.MeasureTheory.Integral.Average
import Mathlib.MeasureTheory.Decomposition.Lebesgue
#align_import measure_theory.covering.differentiation from "leanprover-community/mathlib"@"57ac39bd365c2f80589a700f9fbb664d3a1a30c2"
open MeasureTheory Metric Set Filter TopologicalSpace MeasureTheory.Measure
open scoped Filter ENNReal MeasureTheory NNReal Topology
variable {α : Type*} [MetricSpace α] {m0 : MeasurableSpace α} {μ : Measure α} (v : VitaliFamily μ)
{E : Type*} [NormedAddCommGroup E]
namespace VitaliFamily
noncomputable def limRatio (ρ : Measure α) (x : α) : ℝ≥0∞ :=
limUnder (v.filterAt x) fun a => ρ a / μ a
#align vitali_family.lim_ratio VitaliFamily.limRatio
theorem ae_eventually_measure_pos [SecondCountableTopology α] :
∀ᵐ x ∂μ, ∀ᶠ a in v.filterAt x, 0 < μ a := by
set s := {x | ¬∀ᶠ a in v.filterAt x, 0 < μ a} with hs
simp (config := { zeta := false }) only [not_lt, not_eventually, nonpos_iff_eq_zero] at hs
change μ s = 0
let f : α → Set (Set α) := fun _ => {a | μ a = 0}
have h : v.FineSubfamilyOn f s := by
intro x hx ε εpos
rw [hs] at hx
simp only [frequently_filterAt_iff, exists_prop, gt_iff_lt, mem_setOf_eq] at hx
rcases hx ε εpos with ⟨a, a_sets, ax, μa⟩
exact ⟨a, ⟨a_sets, μa⟩, ax⟩
refine le_antisymm ?_ bot_le
calc
μ s ≤ ∑' x : h.index, μ (h.covering x) := h.measure_le_tsum
_ = ∑' x : h.index, 0 := by congr; ext1 x; exact h.covering_mem x.2
_ = 0 := by simp only [tsum_zero, add_zero]
#align vitali_family.ae_eventually_measure_pos VitaliFamily.ae_eventually_measure_pos
theorem eventually_measure_lt_top [IsLocallyFiniteMeasure μ] (x : α) :
∀ᶠ a in v.filterAt x, μ a < ∞ :=
(μ.finiteAt_nhds x).eventually.filter_mono inf_le_left
#align vitali_family.eventually_measure_lt_top VitaliFamily.eventually_measure_lt_top
theorem measure_le_of_frequently_le [SecondCountableTopology α] [BorelSpace α] {ρ : Measure α}
(ν : Measure α) [IsLocallyFiniteMeasure ν] (hρ : ρ ≪ μ) (s : Set α)
(hs : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, ρ a ≤ ν a) : ρ s ≤ ν s := by
-- this follows from a covering argument using the sets satisfying `ρ a ≤ ν a`.
apply ENNReal.le_of_forall_pos_le_add fun ε εpos _ => ?_
obtain ⟨U, sU, U_open, νU⟩ : ∃ (U : Set α), s ⊆ U ∧ IsOpen U ∧ ν U ≤ ν s + ε :=
exists_isOpen_le_add s ν (ENNReal.coe_pos.2 εpos).ne'
let f : α → Set (Set α) := fun _ => {a | ρ a ≤ ν a ∧ a ⊆ U}
have h : v.FineSubfamilyOn f s := by
apply v.fineSubfamilyOn_of_frequently f s fun x hx => ?_
have :=
(hs x hx).and_eventually
((v.eventually_filterAt_mem_setsAt x).and
(v.eventually_filterAt_subset_of_nhds (U_open.mem_nhds (sU hx))))
apply Frequently.mono this
rintro a ⟨ρa, _, aU⟩
exact ⟨ρa, aU⟩
haveI : Encodable h.index := h.index_countable.toEncodable
calc
ρ s ≤ ∑' x : h.index, ρ (h.covering x) := h.measure_le_tsum_of_absolutelyContinuous hρ
_ ≤ ∑' x : h.index, ν (h.covering x) := ENNReal.tsum_le_tsum fun x => (h.covering_mem x.2).1
_ = ν (⋃ x : h.index, h.covering x) := by
rw [measure_iUnion h.covering_disjoint_subtype fun i => h.measurableSet_u i.2]
_ ≤ ν U := (measure_mono (iUnion_subset fun i => (h.covering_mem i.2).2))
_ ≤ ν s + ε := νU
#align vitali_family.measure_le_of_frequently_le VitaliFamily.measure_le_of_frequently_le
section
variable [SecondCountableTopology α] [BorelSpace α] [IsLocallyFiniteMeasure μ] {ρ : Measure α}
[IsLocallyFiniteMeasure ρ]
theorem ae_eventually_measure_zero_of_singular (hρ : ρ ⟂ₘ μ) :
∀ᵐ x ∂μ, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 0) := by
have A : ∀ ε > (0 : ℝ≥0), ∀ᵐ x ∂μ, ∀ᶠ a in v.filterAt x, ρ a < ε * μ a := by
intro ε εpos
set s := {x | ¬∀ᶠ a in v.filterAt x, ρ a < ε * μ a} with hs
change μ s = 0
obtain ⟨o, _, ρo, μo⟩ : ∃ o : Set α, MeasurableSet o ∧ ρ o = 0 ∧ μ oᶜ = 0 := hρ
apply le_antisymm _ bot_le
calc
μ s ≤ μ (s ∩ o ∪ oᶜ) := by
conv_lhs => rw [← inter_union_compl s o]
gcongr
apply inter_subset_right
_ ≤ μ (s ∩ o) + μ oᶜ := measure_union_le _ _
_ = μ (s ∩ o) := by rw [μo, add_zero]
_ = (ε : ℝ≥0∞)⁻¹ * (ε • μ) (s ∩ o) := by
simp only [coe_nnreal_smul_apply, ← mul_assoc, mul_comm _ (ε : ℝ≥0∞)]
rw [ENNReal.mul_inv_cancel (ENNReal.coe_pos.2 εpos).ne' ENNReal.coe_ne_top, one_mul]
_ ≤ (ε : ℝ≥0∞)⁻¹ * ρ (s ∩ o) := by
gcongr
refine v.measure_le_of_frequently_le ρ ((Measure.AbsolutelyContinuous.refl μ).smul ε) _ ?_
intro x hx
rw [hs] at hx
simp only [mem_inter_iff, not_lt, not_eventually, mem_setOf_eq] at hx
exact hx.1
_ ≤ (ε : ℝ≥0∞)⁻¹ * ρ o := by gcongr; apply inter_subset_right
_ = 0 := by rw [ρo, mul_zero]
obtain ⟨u, _, u_pos, u_lim⟩ :
∃ u : ℕ → ℝ≥0, StrictAnti u ∧ (∀ n : ℕ, 0 < u n) ∧ Tendsto u atTop (𝓝 0) :=
exists_seq_strictAnti_tendsto (0 : ℝ≥0)
have B : ∀ᵐ x ∂μ, ∀ n, ∀ᶠ a in v.filterAt x, ρ a < u n * μ a :=
ae_all_iff.2 fun n => A (u n) (u_pos n)
filter_upwards [B, v.ae_eventually_measure_pos]
intro x hx h'x
refine tendsto_order.2 ⟨fun z hz => (ENNReal.not_lt_zero hz).elim, fun z hz => ?_⟩
obtain ⟨w, w_pos, w_lt⟩ : ∃ w : ℝ≥0, (0 : ℝ≥0∞) < w ∧ (w : ℝ≥0∞) < z :=
ENNReal.lt_iff_exists_nnreal_btwn.1 hz
obtain ⟨n, hn⟩ : ∃ n, u n < w := ((tendsto_order.1 u_lim).2 w (ENNReal.coe_pos.1 w_pos)).exists
filter_upwards [hx n, h'x, v.eventually_measure_lt_top x]
intro a ha μa_pos μa_lt_top
rw [ENNReal.div_lt_iff (Or.inl μa_pos.ne') (Or.inl μa_lt_top.ne)]
exact ha.trans_le (mul_le_mul_right' ((ENNReal.coe_le_coe.2 hn.le).trans w_lt.le) _)
#align vitali_family.ae_eventually_measure_zero_of_singular VitaliFamily.ae_eventually_measure_zero_of_singular
section AbsolutelyContinuous
variable (hρ : ρ ≪ μ)
theorem null_of_frequently_le_of_frequently_ge {c d : ℝ≥0} (hcd : c < d) (s : Set α)
(hc : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, ρ a ≤ c * μ a)
(hd : ∀ x ∈ s, ∃ᶠ a in v.filterAt x, (d : ℝ≥0∞) * μ a ≤ ρ a) : μ s = 0 := by
apply measure_null_of_locally_null s fun x _ => ?_
obtain ⟨o, xo, o_open, μo⟩ : ∃ o : Set α, x ∈ o ∧ IsOpen o ∧ μ o < ∞ :=
Measure.exists_isOpen_measure_lt_top μ x
refine ⟨s ∩ o, inter_mem_nhdsWithin _ (o_open.mem_nhds xo), ?_⟩
let s' := s ∩ o
by_contra h
apply lt_irrefl (ρ s')
calc
ρ s' ≤ c * μ s' := v.measure_le_of_frequently_le (c • μ) hρ s' fun x hx => hc x hx.1
_ < d * μ s' := by
apply (ENNReal.mul_lt_mul_right h _).2 (ENNReal.coe_lt_coe.2 hcd)
exact (lt_of_le_of_lt (measure_mono inter_subset_right) μo).ne
_ ≤ ρ s' :=
v.measure_le_of_frequently_le ρ ((Measure.AbsolutelyContinuous.refl μ).smul d) s' fun x hx =>
hd x hx.1
#align vitali_family.null_of_frequently_le_of_frequently_ge VitaliFamily.null_of_frequently_le_of_frequently_ge
theorem ae_tendsto_div : ∀ᵐ x ∂μ, ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c) := by
obtain ⟨w, w_count, w_dense, _, w_top⟩ :
∃ w : Set ℝ≥0∞, w.Countable ∧ Dense w ∧ 0 ∉ w ∧ ∞ ∉ w :=
ENNReal.exists_countable_dense_no_zero_top
have I : ∀ x ∈ w, x ≠ ∞ := fun x xs hx => w_top (hx ▸ xs)
have A : ∀ c ∈ w, ∀ d ∈ w, c < d → ∀ᵐ x ∂μ,
¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
intro c hc d hd hcd
lift c to ℝ≥0 using I c hc
lift d to ℝ≥0 using I d hd
apply v.null_of_frequently_le_of_frequently_ge hρ (ENNReal.coe_lt_coe.1 hcd)
· simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
mem_setOf_eq, mem_compl_iff, not_forall]
intro x h1x _
apply h1x.mono fun a ha => ?_
refine (ENNReal.div_le_iff_le_mul ?_ (Or.inr (bot_le.trans_lt ha).ne')).1 ha.le
simp only [ENNReal.coe_ne_top, Ne, or_true_iff, not_false_iff]
· simp only [and_imp, exists_prop, not_frequently, not_and, not_lt, not_le, not_eventually,
mem_setOf_eq, mem_compl_iff, not_forall]
intro x _ h2x
apply h2x.mono fun a ha => ?_
exact ENNReal.mul_le_of_le_div ha.le
have B : ∀ᵐ x ∂μ, ∀ c ∈ w, ∀ d ∈ w, c < d →
¬((∃ᶠ a in v.filterAt x, ρ a / μ a < c) ∧ ∃ᶠ a in v.filterAt x, d < ρ a / μ a) := by
#adaptation_note
rw [ae_ball_iff w_count]; intro x hx; rw [ae_ball_iff w_count]; revert x
simpa only [ae_all_iff]
filter_upwards [B]
intro x hx
exact tendsto_of_no_upcrossings w_dense hx
#align vitali_family.ae_tendsto_div VitaliFamily.ae_tendsto_div
theorem ae_tendsto_limRatio :
∀ᵐ x ∂μ, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 (v.limRatio ρ x)) := by
filter_upwards [v.ae_tendsto_div hρ]
intro x hx
exact tendsto_nhds_limUnder hx
#align vitali_family.ae_tendsto_lim_ratio VitaliFamily.ae_tendsto_limRatio
theorem exists_measurable_supersets_limRatio {p q : ℝ≥0} (hpq : p < q) :
∃ a b, MeasurableSet a ∧ MeasurableSet b ∧
{x | v.limRatio ρ x < p} ⊆ a ∧ {x | (q : ℝ≥0∞) < v.limRatio ρ x} ⊆ b ∧ μ (a ∩ b) = 0 := by
let s := {x | ∃ c, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 c)}
let o : ℕ → Set α := spanningSets (ρ + μ)
let u n := s ∩ {x | v.limRatio ρ x < p} ∩ o n
let w n := s ∩ {x | (q : ℝ≥0∞) < v.limRatio ρ x} ∩ o n
-- the supersets are obtained by restricting to the set `s` where the limit is well defined, to
-- a finite measure part `o n`, taking a measurable superset here, and then taking the union over
-- `n`.
refine
⟨toMeasurable μ sᶜ ∪ ⋃ n, toMeasurable (ρ + μ) (u n),
toMeasurable μ sᶜ ∪ ⋃ n, toMeasurable (ρ + μ) (w n), ?_, ?_, ?_, ?_, ?_⟩
-- check that these sets are measurable supersets as required
· exact
(measurableSet_toMeasurable _ _).union
(MeasurableSet.iUnion fun n => measurableSet_toMeasurable _ _)
· exact
(measurableSet_toMeasurable _ _).union
(MeasurableSet.iUnion fun n => measurableSet_toMeasurable _ _)
· intro x hx
by_cases h : x ∈ s
· refine Or.inr (mem_iUnion.2 ⟨spanningSetsIndex (ρ + μ) x, ?_⟩)
exact subset_toMeasurable _ _ ⟨⟨h, hx⟩, mem_spanningSetsIndex _ _⟩
· exact Or.inl (subset_toMeasurable μ sᶜ h)
· intro x hx
by_cases h : x ∈ s
· refine Or.inr (mem_iUnion.2 ⟨spanningSetsIndex (ρ + μ) x, ?_⟩)
exact subset_toMeasurable _ _ ⟨⟨h, hx⟩, mem_spanningSetsIndex _ _⟩
· exact Or.inl (subset_toMeasurable μ sᶜ h)
-- it remains to check the nontrivial part that these sets have zero measure intersection.
-- it suffices to do it for fixed `m` and `n`, as one is taking countable unions.
suffices H : ∀ m n : ℕ, μ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) = 0 by
have A :
(toMeasurable μ sᶜ ∪ ⋃ n, toMeasurable (ρ + μ) (u n)) ∩
(toMeasurable μ sᶜ ∪ ⋃ n, toMeasurable (ρ + μ) (w n)) ⊆
toMeasurable μ sᶜ ∪
⋃ (m) (n), toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n) := by
simp only [inter_union_distrib_left, union_inter_distrib_right, true_and_iff,
subset_union_left, union_subset_iff, inter_self]
refine ⟨?_, ?_, ?_⟩
· exact inter_subset_right.trans subset_union_left
· exact inter_subset_left.trans subset_union_left
· simp_rw [iUnion_inter, inter_iUnion]; exact subset_union_right
refine le_antisymm ((measure_mono A).trans ?_) bot_le
calc
μ (toMeasurable μ sᶜ ∪
⋃ (m) (n), toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) ≤
μ (toMeasurable μ sᶜ) +
μ (⋃ (m) (n), toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) :=
measure_union_le _ _
_ = μ (⋃ (m) (n), toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) := by
have : μ sᶜ = 0 := v.ae_tendsto_div hρ; rw [measure_toMeasurable, this, zero_add]
_ ≤ ∑' (m) (n), μ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) :=
((measure_iUnion_le _).trans (ENNReal.tsum_le_tsum fun m => measure_iUnion_le _))
_ = 0 := by simp only [H, tsum_zero]
-- now starts the nontrivial part of the argument. We fix `m` and `n`, and show that the
-- measurable supersets of `u m` and `w n` have zero measure intersection by using the lemmas
-- `measure_toMeasurable_add_inter_left` (to reduce to `u m` or `w n` instead of the measurable
-- superset) and `measure_le_of_frequently_le` to compare their measures for `ρ` and `μ`.
intro m n
have I : (ρ + μ) (u m) ≠ ∞ := by
apply (lt_of_le_of_lt (measure_mono _) (measure_spanningSets_lt_top (ρ + μ) m)).ne
exact inter_subset_right
have J : (ρ + μ) (w n) ≠ ∞ := by
apply (lt_of_le_of_lt (measure_mono _) (measure_spanningSets_lt_top (ρ + μ) n)).ne
exact inter_subset_right
have A :
ρ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) ≤
p * μ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) :=
calc
ρ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) =
ρ (u m ∩ toMeasurable (ρ + μ) (w n)) :=
measure_toMeasurable_add_inter_left (measurableSet_toMeasurable _ _) I
_ ≤ (p • μ) (u m ∩ toMeasurable (ρ + μ) (w n)) := by
refine v.measure_le_of_frequently_le (p • μ) hρ _ fun x hx => ?_
have L : Tendsto (fun a : Set α => ρ a / μ a) (v.filterAt x) (𝓝 (v.limRatio ρ x)) :=
tendsto_nhds_limUnder hx.1.1.1
have I : ∀ᶠ b : Set α in v.filterAt x, ρ b / μ b < p := (tendsto_order.1 L).2 _ hx.1.1.2
apply I.frequently.mono fun a ha => ?_
rw [coe_nnreal_smul_apply]
refine (ENNReal.div_le_iff_le_mul ?_ (Or.inr (bot_le.trans_lt ha).ne')).1 ha.le
simp only [ENNReal.coe_ne_top, Ne, or_true_iff, not_false_iff]
_ = p * μ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) := by
simp only [coe_nnreal_smul_apply,
measure_toMeasurable_add_inter_right (measurableSet_toMeasurable _ _) I]
have B :
(q : ℝ≥0∞) * μ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) ≤
ρ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) :=
calc
(q : ℝ≥0∞) * μ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) =
(q : ℝ≥0∞) * μ (toMeasurable (ρ + μ) (u m) ∩ w n) := by
conv_rhs => rw [inter_comm]
rw [inter_comm, measure_toMeasurable_add_inter_right (measurableSet_toMeasurable _ _) J]
_ ≤ ρ (toMeasurable (ρ + μ) (u m) ∩ w n) := by
rw [← coe_nnreal_smul_apply]
refine v.measure_le_of_frequently_le _ (AbsolutelyContinuous.rfl.smul _) _ ?_
intro x hx
have L : Tendsto (fun a : Set α => ρ a / μ a) (v.filterAt x) (𝓝 (v.limRatio ρ x)) :=
tendsto_nhds_limUnder hx.2.1.1
have I : ∀ᶠ b : Set α in v.filterAt x, (q : ℝ≥0∞) < ρ b / μ b :=
(tendsto_order.1 L).1 _ hx.2.1.2
apply I.frequently.mono fun a ha => ?_
rw [coe_nnreal_smul_apply]
exact ENNReal.mul_le_of_le_div ha.le
_ = ρ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) := by
conv_rhs => rw [inter_comm]
rw [inter_comm]
exact (measure_toMeasurable_add_inter_left (measurableSet_toMeasurable _ _) J).symm
by_contra h
apply lt_irrefl (ρ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)))
calc
ρ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) ≤
p * μ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) :=
A
_ < q * μ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) := by
gcongr
suffices H : (ρ + μ) (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) ≠ ∞ by
simp only [not_or, ENNReal.add_eq_top, Pi.add_apply, Ne, coe_add] at H
exact H.2
apply (lt_of_le_of_lt (measure_mono inter_subset_left) _).ne
rw [measure_toMeasurable]
apply lt_of_le_of_lt (measure_mono _) (measure_spanningSets_lt_top (ρ + μ) m)
exact inter_subset_right
_ ≤ ρ (toMeasurable (ρ + μ) (u m) ∩ toMeasurable (ρ + μ) (w n)) := B
#align vitali_family.exists_measurable_supersets_lim_ratio VitaliFamily.exists_measurable_supersets_limRatio
theorem aemeasurable_limRatio : AEMeasurable (v.limRatio ρ) μ := by
apply ENNReal.aemeasurable_of_exist_almost_disjoint_supersets _ _ fun p q hpq => ?_
exact v.exists_measurable_supersets_limRatio hρ hpq
#align vitali_family.ae_measurable_lim_ratio VitaliFamily.aemeasurable_limRatio
noncomputable def limRatioMeas : α → ℝ≥0∞ :=
(v.aemeasurable_limRatio hρ).mk _
#align vitali_family.lim_ratio_meas VitaliFamily.limRatioMeas
theorem limRatioMeas_measurable : Measurable (v.limRatioMeas hρ) :=
AEMeasurable.measurable_mk _
#align vitali_family.lim_ratio_meas_measurable VitaliFamily.limRatioMeas_measurable
theorem ae_tendsto_limRatioMeas :
∀ᵐ x ∂μ, Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 (v.limRatioMeas hρ x)) := by
filter_upwards [v.ae_tendsto_limRatio hρ, AEMeasurable.ae_eq_mk (v.aemeasurable_limRatio hρ)]
intro x hx h'x
rwa [h'x] at hx
#align vitali_family.ae_tendsto_lim_ratio_meas VitaliFamily.ae_tendsto_limRatioMeas
theorem measure_le_mul_of_subset_limRatioMeas_lt {p : ℝ≥0} {s : Set α}
(h : s ⊆ {x | v.limRatioMeas hρ x < p}) : ρ s ≤ p * μ s := by
let t := {x : α | Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 (v.limRatioMeas hρ x))}
have A : μ tᶜ = 0 := v.ae_tendsto_limRatioMeas hρ
suffices H : ρ (s ∩ t) ≤ (p • μ) (s ∩ t) by calc
ρ s = ρ (s ∩ t ∪ s ∩ tᶜ) := by rw [inter_union_compl]
_ ≤ ρ (s ∩ t) + ρ (s ∩ tᶜ) := measure_union_le _ _
_ ≤ (p • μ) (s ∩ t) + ρ tᶜ := by gcongr; apply inter_subset_right
_ ≤ p * μ (s ∩ t) := by simp [(hρ A)]
_ ≤ p * μ s := by gcongr; apply inter_subset_left
refine v.measure_le_of_frequently_le (p • μ) hρ _ fun x hx => ?_
have I : ∀ᶠ b : Set α in v.filterAt x, ρ b / μ b < p := (tendsto_order.1 hx.2).2 _ (h hx.1)
apply I.frequently.mono fun a ha => ?_
rw [coe_nnreal_smul_apply]
refine (ENNReal.div_le_iff_le_mul ?_ (Or.inr (bot_le.trans_lt ha).ne')).1 ha.le
simp only [ENNReal.coe_ne_top, Ne, or_true_iff, not_false_iff]
#align vitali_family.measure_le_mul_of_subset_lim_ratio_meas_lt VitaliFamily.measure_le_mul_of_subset_limRatioMeas_lt
theorem mul_measure_le_of_subset_lt_limRatioMeas {q : ℝ≥0} {s : Set α}
(h : s ⊆ {x | (q : ℝ≥0∞) < v.limRatioMeas hρ x}) : (q : ℝ≥0∞) * μ s ≤ ρ s := by
let t := {x : α | Tendsto (fun a => ρ a / μ a) (v.filterAt x) (𝓝 (v.limRatioMeas hρ x))}
have A : μ tᶜ = 0 := v.ae_tendsto_limRatioMeas hρ
suffices H : (q • μ) (s ∩ t) ≤ ρ (s ∩ t) by calc
(q • μ) s = (q • μ) (s ∩ t ∪ s ∩ tᶜ) := by rw [inter_union_compl]
_ ≤ (q • μ) (s ∩ t) + (q • μ) (s ∩ tᶜ) := measure_union_le _ _
_ ≤ ρ (s ∩ t) + (q • μ) tᶜ := by gcongr; apply inter_subset_right
_ = ρ (s ∩ t) := by simp [A]
_ ≤ ρ s := by gcongr; apply inter_subset_left
refine v.measure_le_of_frequently_le _ (AbsolutelyContinuous.rfl.smul _) _ ?_
intro x hx
have I : ∀ᶠ a in v.filterAt x, (q : ℝ≥0∞) < ρ a / μ a := (tendsto_order.1 hx.2).1 _ (h hx.1)
apply I.frequently.mono fun a ha => ?_
rw [coe_nnreal_smul_apply]
exact ENNReal.mul_le_of_le_div ha.le
#align vitali_family.mul_measure_le_of_subset_lt_lim_ratio_meas VitaliFamily.mul_measure_le_of_subset_lt_limRatioMeas
theorem measure_limRatioMeas_top : μ {x | v.limRatioMeas hρ x = ∞} = 0 := by
refine measure_null_of_locally_null _ fun x _ => ?_
obtain ⟨o, xo, o_open, μo⟩ : ∃ o : Set α, x ∈ o ∧ IsOpen o ∧ ρ o < ∞ :=
Measure.exists_isOpen_measure_lt_top ρ x
let s := {x : α | v.limRatioMeas hρ x = ∞} ∩ o
refine ⟨s, inter_mem_nhdsWithin _ (o_open.mem_nhds xo), le_antisymm ?_ bot_le⟩
have ρs : ρ s ≠ ∞ := ((measure_mono inter_subset_right).trans_lt μo).ne
have A : ∀ q : ℝ≥0, 1 ≤ q → μ s ≤ (q : ℝ≥0∞)⁻¹ * ρ s := by
intro q hq
rw [mul_comm, ← div_eq_mul_inv, ENNReal.le_div_iff_mul_le _ (Or.inr ρs), mul_comm]
· apply v.mul_measure_le_of_subset_lt_limRatioMeas hρ
intro y hy
have : v.limRatioMeas hρ y = ∞ := hy.1
simp only [this, ENNReal.coe_lt_top, mem_setOf_eq]
· simp only [(zero_lt_one.trans_le hq).ne', true_or_iff, ENNReal.coe_eq_zero, Ne,
not_false_iff]
have B : Tendsto (fun q : ℝ≥0 => (q : ℝ≥0∞)⁻¹ * ρ s) atTop (𝓝 (∞⁻¹ * ρ s)) := by
apply ENNReal.Tendsto.mul_const _ (Or.inr ρs)
exact ENNReal.tendsto_inv_iff.2 (ENNReal.tendsto_coe_nhds_top.2 tendsto_id)
simp only [zero_mul, ENNReal.inv_top] at B
apply ge_of_tendsto B
exact eventually_atTop.2 ⟨1, A⟩
#align vitali_family.measure_lim_ratio_meas_top VitaliFamily.measure_limRatioMeas_top
theorem measure_limRatioMeas_zero : ρ {x | v.limRatioMeas hρ x = 0} = 0 := by
refine measure_null_of_locally_null _ fun x _ => ?_
obtain ⟨o, xo, o_open, μo⟩ : ∃ o : Set α, x ∈ o ∧ IsOpen o ∧ μ o < ∞ :=
Measure.exists_isOpen_measure_lt_top μ x
let s := {x : α | v.limRatioMeas hρ x = 0} ∩ o
refine ⟨s, inter_mem_nhdsWithin _ (o_open.mem_nhds xo), le_antisymm ?_ bot_le⟩
have μs : μ s ≠ ∞ := ((measure_mono inter_subset_right).trans_lt μo).ne
have A : ∀ q : ℝ≥0, 0 < q → ρ s ≤ q * μ s := by
intro q hq
apply v.measure_le_mul_of_subset_limRatioMeas_lt hρ
intro y hy
have : v.limRatioMeas hρ y = 0 := hy.1
simp only [this, mem_setOf_eq, hq, ENNReal.coe_pos]
have B : Tendsto (fun q : ℝ≥0 => (q : ℝ≥0∞) * μ s) (𝓝[>] (0 : ℝ≥0)) (𝓝 ((0 : ℝ≥0) * μ s)) := by
apply ENNReal.Tendsto.mul_const _ (Or.inr μs)
rw [ENNReal.tendsto_coe]
exact nhdsWithin_le_nhds
simp only [zero_mul, ENNReal.coe_zero] at B
apply ge_of_tendsto B
filter_upwards [self_mem_nhdsWithin] using A
#align vitali_family.measure_lim_ratio_meas_zero VitaliFamily.measure_limRatioMeas_zero
| Mathlib/MeasureTheory/Covering/Differentiation.lean | 533 | 599 | theorem withDensity_le_mul {s : Set α} (hs : MeasurableSet s) {t : ℝ≥0} (ht : 1 < t) :
μ.withDensity (v.limRatioMeas hρ) s ≤ (t : ℝ≥0∞) ^ 2 * ρ s := by |
/- We cut `s` into the sets where `v.limRatioMeas hρ = 0`, where `v.limRatioMeas hρ = ∞`, and
where `v.limRatioMeas hρ ∈ [t^n, t^(n+1))` for `n : ℤ`. The first and second have measure `0`.
For the latter, since `v.limRatioMeas hρ` fluctuates by at most `t` on this slice, we can use
`measure_le_mul_of_subset_limRatioMeas_lt` and `mul_measure_le_of_subset_lt_limRatioMeas` to
show that the two measures are comparable up to `t` (in fact `t^2` for technical reasons of
strict inequalities). -/
have t_ne_zero' : t ≠ 0 := (zero_lt_one.trans ht).ne'
have t_ne_zero : (t : ℝ≥0∞) ≠ 0 := by simpa only [ENNReal.coe_eq_zero, Ne] using t_ne_zero'
let ν := μ.withDensity (v.limRatioMeas hρ)
let f := v.limRatioMeas hρ
have f_meas : Measurable f := v.limRatioMeas_measurable hρ
-- Note(kmill): smul elaborator when used for CoeFun fails to get CoeFun instance to trigger
-- unless you use the `(... :)` notation. Another fix is using `(2 : Nat)`, so this appears
-- to be an unpleasant interaction with default instances.
have A : ν (s ∩ f ⁻¹' {0}) ≤ ((t : ℝ≥0∞) ^ 2 • ρ :) (s ∩ f ⁻¹' {0}) := by
apply le_trans _ (zero_le _)
have M : MeasurableSet (s ∩ f ⁻¹' {0}) := hs.inter (f_meas (measurableSet_singleton _))
simp only [ν, nonpos_iff_eq_zero, M, withDensity_apply, lintegral_eq_zero_iff f_meas]
apply (ae_restrict_iff' M).2
exact eventually_of_forall fun x hx => hx.2
have B : ν (s ∩ f ⁻¹' {∞}) ≤ ((t : ℝ≥0∞) ^ 2 • ρ :) (s ∩ f ⁻¹' {∞}) := by
apply le_trans (le_of_eq _) (zero_le _)
apply withDensity_absolutelyContinuous μ _
rw [← nonpos_iff_eq_zero]
exact (measure_mono inter_subset_right).trans (v.measure_limRatioMeas_top hρ).le
have C :
∀ n : ℤ,
ν (s ∩ f ⁻¹' Ico ((t : ℝ≥0∞) ^ n) ((t : ℝ≥0∞) ^ (n + 1))) ≤
((t : ℝ≥0∞) ^ 2 • ρ :) (s ∩ f ⁻¹' Ico ((t : ℝ≥0∞) ^ n) ((t : ℝ≥0∞) ^ (n + 1))) := by
intro n
let I := Ico ((t : ℝ≥0∞) ^ n) ((t : ℝ≥0∞) ^ (n + 1))
have M : MeasurableSet (s ∩ f ⁻¹' I) := hs.inter (f_meas measurableSet_Ico)
simp only [ν, M, withDensity_apply, coe_nnreal_smul_apply]
calc
(∫⁻ x in s ∩ f ⁻¹' I, f x ∂μ) ≤ ∫⁻ _ in s ∩ f ⁻¹' I, (t : ℝ≥0∞) ^ (n + 1) ∂μ :=
lintegral_mono_ae ((ae_restrict_iff' M).2 (eventually_of_forall fun x hx => hx.2.2.le))
_ = (t : ℝ≥0∞) ^ (n + 1) * μ (s ∩ f ⁻¹' I) := by
simp only [lintegral_const, MeasurableSet.univ, Measure.restrict_apply, univ_inter]
_ = (t : ℝ≥0∞) ^ (2 : ℤ) * ((t : ℝ≥0∞) ^ (n - 1) * μ (s ∩ f ⁻¹' I)) := by
rw [← mul_assoc, ← ENNReal.zpow_add t_ne_zero ENNReal.coe_ne_top]
congr 2
abel
_ ≤ (t : ℝ≥0∞) ^ (2 : ℤ) * ρ (s ∩ f ⁻¹' I) := by
gcongr
rw [← ENNReal.coe_zpow (zero_lt_one.trans ht).ne']
apply v.mul_measure_le_of_subset_lt_limRatioMeas hρ
intro x hx
apply lt_of_lt_of_le _ hx.2.1
rw [← ENNReal.coe_zpow (zero_lt_one.trans ht).ne', ENNReal.coe_lt_coe, sub_eq_add_neg,
zpow_add₀ t_ne_zero']
conv_rhs => rw [← mul_one (t ^ n)]
gcongr
rw [zpow_neg_one]
exact inv_lt_one ht
calc
ν s =
ν (s ∩ f ⁻¹' {0}) + ν (s ∩ f ⁻¹' {∞}) +
∑' n : ℤ, ν (s ∩ f ⁻¹' Ico ((t : ℝ≥0∞) ^ n) ((t : ℝ≥0∞) ^ (n + 1))) :=
measure_eq_measure_preimage_add_measure_tsum_Ico_zpow ν f_meas hs ht
_ ≤
((t : ℝ≥0∞) ^ 2 • ρ :) (s ∩ f ⁻¹' {0}) + ((t : ℝ≥0∞) ^ 2 • ρ :) (s ∩ f ⁻¹' {∞}) +
∑' n : ℤ, ((t : ℝ≥0∞) ^ 2 • ρ :) (s ∩ f ⁻¹' Ico (t ^ n) (t ^ (n + 1))) :=
(add_le_add (add_le_add A B) (ENNReal.tsum_le_tsum C))
_ = ((t : ℝ≥0∞) ^ 2 • ρ :) s :=
(measure_eq_measure_preimage_add_measure_tsum_Ico_zpow ((t : ℝ≥0∞) ^ 2 • ρ) f_meas hs ht).symm
|
import Mathlib.MeasureTheory.Measure.MeasureSpace
open scoped ENNReal NNReal Topology
open Set MeasureTheory Measure Filter MeasurableSpace ENNReal Function
variable {R α β δ γ ι : Type*}
namespace MeasureTheory
variable {m0 : MeasurableSpace α} [MeasurableSpace β] [MeasurableSpace γ]
variable {μ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α} {s s' t : Set α}
namespace Measure
noncomputable def restrictₗ {m0 : MeasurableSpace α} (s : Set α) : Measure α →ₗ[ℝ≥0∞] Measure α :=
liftLinear (OuterMeasure.restrict s) fun μ s' hs' t => by
suffices μ (s ∩ t) = μ (s ∩ t ∩ s') + μ ((s ∩ t) \ s') by
simpa [← Set.inter_assoc, Set.inter_comm _ s, ← inter_diff_assoc]
exact le_toOuterMeasure_caratheodory _ _ hs' _
#align measure_theory.measure.restrictₗ MeasureTheory.Measure.restrictₗ
noncomputable def restrict {_m0 : MeasurableSpace α} (μ : Measure α) (s : Set α) : Measure α :=
restrictₗ s μ
#align measure_theory.measure.restrict MeasureTheory.Measure.restrict
@[simp]
theorem restrictₗ_apply {_m0 : MeasurableSpace α} (s : Set α) (μ : Measure α) :
restrictₗ s μ = μ.restrict s :=
rfl
#align measure_theory.measure.restrictₗ_apply MeasureTheory.Measure.restrictₗ_apply
theorem restrict_toOuterMeasure_eq_toOuterMeasure_restrict (h : MeasurableSet s) :
(μ.restrict s).toOuterMeasure = OuterMeasure.restrict s μ.toOuterMeasure := by
simp_rw [restrict, restrictₗ, liftLinear, LinearMap.coe_mk, AddHom.coe_mk,
toMeasure_toOuterMeasure, OuterMeasure.restrict_trim h, μ.trimmed]
#align measure_theory.measure.restrict_to_outer_measure_eq_to_outer_measure_restrict MeasureTheory.Measure.restrict_toOuterMeasure_eq_toOuterMeasure_restrict
theorem restrict_apply₀ (ht : NullMeasurableSet t (μ.restrict s)) : μ.restrict s t = μ (t ∩ s) := by
rw [← restrictₗ_apply, restrictₗ, liftLinear_apply₀ _ ht, OuterMeasure.restrict_apply,
coe_toOuterMeasure]
#align measure_theory.measure.restrict_apply₀ MeasureTheory.Measure.restrict_apply₀
@[simp]
theorem restrict_apply (ht : MeasurableSet t) : μ.restrict s t = μ (t ∩ s) :=
restrict_apply₀ ht.nullMeasurableSet
#align measure_theory.measure.restrict_apply MeasureTheory.Measure.restrict_apply
theorem restrict_mono' {_m0 : MeasurableSpace α} ⦃s s' : Set α⦄ ⦃μ ν : Measure α⦄ (hs : s ≤ᵐ[μ] s')
(hμν : μ ≤ ν) : μ.restrict s ≤ ν.restrict s' :=
Measure.le_iff.2 fun t ht => calc
μ.restrict s t = μ (t ∩ s) := restrict_apply ht
_ ≤ μ (t ∩ s') := (measure_mono_ae <| hs.mono fun _x hx ⟨hxt, hxs⟩ => ⟨hxt, hx hxs⟩)
_ ≤ ν (t ∩ s') := le_iff'.1 hμν (t ∩ s')
_ = ν.restrict s' t := (restrict_apply ht).symm
#align measure_theory.measure.restrict_mono' MeasureTheory.Measure.restrict_mono'
@[mono]
theorem restrict_mono {_m0 : MeasurableSpace α} ⦃s s' : Set α⦄ (hs : s ⊆ s') ⦃μ ν : Measure α⦄
(hμν : μ ≤ ν) : μ.restrict s ≤ ν.restrict s' :=
restrict_mono' (ae_of_all _ hs) hμν
#align measure_theory.measure.restrict_mono MeasureTheory.Measure.restrict_mono
theorem restrict_mono_ae (h : s ≤ᵐ[μ] t) : μ.restrict s ≤ μ.restrict t :=
restrict_mono' h (le_refl μ)
#align measure_theory.measure.restrict_mono_ae MeasureTheory.Measure.restrict_mono_ae
theorem restrict_congr_set (h : s =ᵐ[μ] t) : μ.restrict s = μ.restrict t :=
le_antisymm (restrict_mono_ae h.le) (restrict_mono_ae h.symm.le)
#align measure_theory.measure.restrict_congr_set MeasureTheory.Measure.restrict_congr_set
@[simp]
theorem restrict_apply' (hs : MeasurableSet s) : μ.restrict s t = μ (t ∩ s) := by
rw [← toOuterMeasure_apply,
Measure.restrict_toOuterMeasure_eq_toOuterMeasure_restrict hs,
OuterMeasure.restrict_apply s t _, toOuterMeasure_apply]
#align measure_theory.measure.restrict_apply' MeasureTheory.Measure.restrict_apply'
theorem restrict_apply₀' (hs : NullMeasurableSet s μ) : μ.restrict s t = μ (t ∩ s) := by
rw [← restrict_congr_set hs.toMeasurable_ae_eq,
restrict_apply' (measurableSet_toMeasurable _ _),
measure_congr ((ae_eq_refl t).inter hs.toMeasurable_ae_eq)]
#align measure_theory.measure.restrict_apply₀' MeasureTheory.Measure.restrict_apply₀'
theorem restrict_le_self : μ.restrict s ≤ μ :=
Measure.le_iff.2 fun t ht => calc
μ.restrict s t = μ (t ∩ s) := restrict_apply ht
_ ≤ μ t := measure_mono inter_subset_left
#align measure_theory.measure.restrict_le_self MeasureTheory.Measure.restrict_le_self
variable (μ)
theorem restrict_eq_self (h : s ⊆ t) : μ.restrict t s = μ s :=
(le_iff'.1 restrict_le_self s).antisymm <|
calc
μ s ≤ μ (toMeasurable (μ.restrict t) s ∩ t) :=
measure_mono (subset_inter (subset_toMeasurable _ _) h)
_ = μ.restrict t s := by
rw [← restrict_apply (measurableSet_toMeasurable _ _), measure_toMeasurable]
#align measure_theory.measure.restrict_eq_self MeasureTheory.Measure.restrict_eq_self
@[simp]
theorem restrict_apply_self (s : Set α) : (μ.restrict s) s = μ s :=
restrict_eq_self μ Subset.rfl
#align measure_theory.measure.restrict_apply_self MeasureTheory.Measure.restrict_apply_self
variable {μ}
theorem restrict_apply_univ (s : Set α) : μ.restrict s univ = μ s := by
rw [restrict_apply MeasurableSet.univ, Set.univ_inter]
#align measure_theory.measure.restrict_apply_univ MeasureTheory.Measure.restrict_apply_univ
theorem le_restrict_apply (s t : Set α) : μ (t ∩ s) ≤ μ.restrict s t :=
calc
μ (t ∩ s) = μ.restrict s (t ∩ s) := (restrict_eq_self μ inter_subset_right).symm
_ ≤ μ.restrict s t := measure_mono inter_subset_left
#align measure_theory.measure.le_restrict_apply MeasureTheory.Measure.le_restrict_apply
theorem restrict_apply_le (s t : Set α) : μ.restrict s t ≤ μ t :=
Measure.le_iff'.1 restrict_le_self _
theorem restrict_apply_superset (h : s ⊆ t) : μ.restrict s t = μ s :=
((measure_mono (subset_univ _)).trans_eq <| restrict_apply_univ _).antisymm
((restrict_apply_self μ s).symm.trans_le <| measure_mono h)
#align measure_theory.measure.restrict_apply_superset MeasureTheory.Measure.restrict_apply_superset
@[simp]
theorem restrict_add {_m0 : MeasurableSpace α} (μ ν : Measure α) (s : Set α) :
(μ + ν).restrict s = μ.restrict s + ν.restrict s :=
(restrictₗ s).map_add μ ν
#align measure_theory.measure.restrict_add MeasureTheory.Measure.restrict_add
@[simp]
theorem restrict_zero {_m0 : MeasurableSpace α} (s : Set α) : (0 : Measure α).restrict s = 0 :=
(restrictₗ s).map_zero
#align measure_theory.measure.restrict_zero MeasureTheory.Measure.restrict_zero
@[simp]
theorem restrict_smul {_m0 : MeasurableSpace α} (c : ℝ≥0∞) (μ : Measure α) (s : Set α) :
(c • μ).restrict s = c • μ.restrict s :=
(restrictₗ s).map_smul c μ
#align measure_theory.measure.restrict_smul MeasureTheory.Measure.restrict_smul
theorem restrict_restrict₀ (hs : NullMeasurableSet s (μ.restrict t)) :
(μ.restrict t).restrict s = μ.restrict (s ∩ t) :=
ext fun u hu => by
simp only [Set.inter_assoc, restrict_apply hu,
restrict_apply₀ (hu.nullMeasurableSet.inter hs)]
#align measure_theory.measure.restrict_restrict₀ MeasureTheory.Measure.restrict_restrict₀
@[simp]
theorem restrict_restrict (hs : MeasurableSet s) : (μ.restrict t).restrict s = μ.restrict (s ∩ t) :=
restrict_restrict₀ hs.nullMeasurableSet
#align measure_theory.measure.restrict_restrict MeasureTheory.Measure.restrict_restrict
theorem restrict_restrict_of_subset (h : s ⊆ t) : (μ.restrict t).restrict s = μ.restrict s := by
ext1 u hu
rw [restrict_apply hu, restrict_apply hu, restrict_eq_self]
exact inter_subset_right.trans h
#align measure_theory.measure.restrict_restrict_of_subset MeasureTheory.Measure.restrict_restrict_of_subset
theorem restrict_restrict₀' (ht : NullMeasurableSet t μ) :
(μ.restrict t).restrict s = μ.restrict (s ∩ t) :=
ext fun u hu => by simp only [restrict_apply hu, restrict_apply₀' ht, inter_assoc]
#align measure_theory.measure.restrict_restrict₀' MeasureTheory.Measure.restrict_restrict₀'
theorem restrict_restrict' (ht : MeasurableSet t) :
(μ.restrict t).restrict s = μ.restrict (s ∩ t) :=
restrict_restrict₀' ht.nullMeasurableSet
#align measure_theory.measure.restrict_restrict' MeasureTheory.Measure.restrict_restrict'
theorem restrict_comm (hs : MeasurableSet s) :
(μ.restrict t).restrict s = (μ.restrict s).restrict t := by
rw [restrict_restrict hs, restrict_restrict' hs, inter_comm]
#align measure_theory.measure.restrict_comm MeasureTheory.Measure.restrict_comm
theorem restrict_apply_eq_zero (ht : MeasurableSet t) : μ.restrict s t = 0 ↔ μ (t ∩ s) = 0 := by
rw [restrict_apply ht]
#align measure_theory.measure.restrict_apply_eq_zero MeasureTheory.Measure.restrict_apply_eq_zero
theorem measure_inter_eq_zero_of_restrict (h : μ.restrict s t = 0) : μ (t ∩ s) = 0 :=
nonpos_iff_eq_zero.1 (h ▸ le_restrict_apply _ _)
#align measure_theory.measure.measure_inter_eq_zero_of_restrict MeasureTheory.Measure.measure_inter_eq_zero_of_restrict
theorem restrict_apply_eq_zero' (hs : MeasurableSet s) : μ.restrict s t = 0 ↔ μ (t ∩ s) = 0 := by
rw [restrict_apply' hs]
#align measure_theory.measure.restrict_apply_eq_zero' MeasureTheory.Measure.restrict_apply_eq_zero'
@[simp]
theorem restrict_eq_zero : μ.restrict s = 0 ↔ μ s = 0 := by
rw [← measure_univ_eq_zero, restrict_apply_univ]
#align measure_theory.measure.restrict_eq_zero MeasureTheory.Measure.restrict_eq_zero
instance restrict.neZero [NeZero (μ s)] : NeZero (μ.restrict s) :=
⟨mt restrict_eq_zero.mp <| NeZero.ne _⟩
theorem restrict_zero_set {s : Set α} (h : μ s = 0) : μ.restrict s = 0 :=
restrict_eq_zero.2 h
#align measure_theory.measure.restrict_zero_set MeasureTheory.Measure.restrict_zero_set
@[simp]
theorem restrict_empty : μ.restrict ∅ = 0 :=
restrict_zero_set measure_empty
#align measure_theory.measure.restrict_empty MeasureTheory.Measure.restrict_empty
@[simp]
theorem restrict_univ : μ.restrict univ = μ :=
ext fun s hs => by simp [hs]
#align measure_theory.measure.restrict_univ MeasureTheory.Measure.restrict_univ
theorem restrict_inter_add_diff₀ (s : Set α) (ht : NullMeasurableSet t μ) :
μ.restrict (s ∩ t) + μ.restrict (s \ t) = μ.restrict s := by
ext1 u hu
simp only [add_apply, restrict_apply hu, ← inter_assoc, diff_eq]
exact measure_inter_add_diff₀ (u ∩ s) ht
#align measure_theory.measure.restrict_inter_add_diff₀ MeasureTheory.Measure.restrict_inter_add_diff₀
theorem restrict_inter_add_diff (s : Set α) (ht : MeasurableSet t) :
μ.restrict (s ∩ t) + μ.restrict (s \ t) = μ.restrict s :=
restrict_inter_add_diff₀ s ht.nullMeasurableSet
#align measure_theory.measure.restrict_inter_add_diff MeasureTheory.Measure.restrict_inter_add_diff
theorem restrict_union_add_inter₀ (s : Set α) (ht : NullMeasurableSet t μ) :
μ.restrict (s ∪ t) + μ.restrict (s ∩ t) = μ.restrict s + μ.restrict t := by
rw [← restrict_inter_add_diff₀ (s ∪ t) ht, union_inter_cancel_right, union_diff_right, ←
restrict_inter_add_diff₀ s ht, add_comm, ← add_assoc, add_right_comm]
#align measure_theory.measure.restrict_union_add_inter₀ MeasureTheory.Measure.restrict_union_add_inter₀
theorem restrict_union_add_inter (s : Set α) (ht : MeasurableSet t) :
μ.restrict (s ∪ t) + μ.restrict (s ∩ t) = μ.restrict s + μ.restrict t :=
restrict_union_add_inter₀ s ht.nullMeasurableSet
#align measure_theory.measure.restrict_union_add_inter MeasureTheory.Measure.restrict_union_add_inter
theorem restrict_union_add_inter' (hs : MeasurableSet s) (t : Set α) :
μ.restrict (s ∪ t) + μ.restrict (s ∩ t) = μ.restrict s + μ.restrict t := by
simpa only [union_comm, inter_comm, add_comm] using restrict_union_add_inter t hs
#align measure_theory.measure.restrict_union_add_inter' MeasureTheory.Measure.restrict_union_add_inter'
theorem restrict_union₀ (h : AEDisjoint μ s t) (ht : NullMeasurableSet t μ) :
μ.restrict (s ∪ t) = μ.restrict s + μ.restrict t := by
simp [← restrict_union_add_inter₀ s ht, restrict_zero_set h]
#align measure_theory.measure.restrict_union₀ MeasureTheory.Measure.restrict_union₀
theorem restrict_union (h : Disjoint s t) (ht : MeasurableSet t) :
μ.restrict (s ∪ t) = μ.restrict s + μ.restrict t :=
restrict_union₀ h.aedisjoint ht.nullMeasurableSet
#align measure_theory.measure.restrict_union MeasureTheory.Measure.restrict_union
theorem restrict_union' (h : Disjoint s t) (hs : MeasurableSet s) :
μ.restrict (s ∪ t) = μ.restrict s + μ.restrict t := by
rw [union_comm, restrict_union h.symm hs, add_comm]
#align measure_theory.measure.restrict_union' MeasureTheory.Measure.restrict_union'
@[simp]
theorem restrict_add_restrict_compl (hs : MeasurableSet s) :
μ.restrict s + μ.restrict sᶜ = μ := by
rw [← restrict_union (@disjoint_compl_right (Set α) _ _) hs.compl, union_compl_self,
restrict_univ]
#align measure_theory.measure.restrict_add_restrict_compl MeasureTheory.Measure.restrict_add_restrict_compl
@[simp]
theorem restrict_compl_add_restrict (hs : MeasurableSet s) : μ.restrict sᶜ + μ.restrict s = μ := by
rw [add_comm, restrict_add_restrict_compl hs]
#align measure_theory.measure.restrict_compl_add_restrict MeasureTheory.Measure.restrict_compl_add_restrict
theorem restrict_union_le (s s' : Set α) : μ.restrict (s ∪ s') ≤ μ.restrict s + μ.restrict s' :=
le_iff.2 fun t ht ↦ by
simpa [ht, inter_union_distrib_left] using measure_union_le (t ∩ s) (t ∩ s')
#align measure_theory.measure.restrict_union_le MeasureTheory.Measure.restrict_union_le
theorem restrict_iUnion_apply_ae [Countable ι] {s : ι → Set α} (hd : Pairwise (AEDisjoint μ on s))
(hm : ∀ i, NullMeasurableSet (s i) μ) {t : Set α} (ht : MeasurableSet t) :
μ.restrict (⋃ i, s i) t = ∑' i, μ.restrict (s i) t := by
simp only [restrict_apply, ht, inter_iUnion]
exact
measure_iUnion₀ (hd.mono fun i j h => h.mono inter_subset_right inter_subset_right)
fun i => ht.nullMeasurableSet.inter (hm i)
#align measure_theory.measure.restrict_Union_apply_ae MeasureTheory.Measure.restrict_iUnion_apply_ae
theorem restrict_iUnion_apply [Countable ι] {s : ι → Set α} (hd : Pairwise (Disjoint on s))
(hm : ∀ i, MeasurableSet (s i)) {t : Set α} (ht : MeasurableSet t) :
μ.restrict (⋃ i, s i) t = ∑' i, μ.restrict (s i) t :=
restrict_iUnion_apply_ae hd.aedisjoint (fun i => (hm i).nullMeasurableSet) ht
#align measure_theory.measure.restrict_Union_apply MeasureTheory.Measure.restrict_iUnion_apply
theorem restrict_iUnion_apply_eq_iSup [Countable ι] {s : ι → Set α} (hd : Directed (· ⊆ ·) s)
{t : Set α} (ht : MeasurableSet t) : μ.restrict (⋃ i, s i) t = ⨆ i, μ.restrict (s i) t := by
simp only [restrict_apply ht, inter_iUnion]
rw [measure_iUnion_eq_iSup]
exacts [hd.mono_comp _ fun s₁ s₂ => inter_subset_inter_right _]
#align measure_theory.measure.restrict_Union_apply_eq_supr MeasureTheory.Measure.restrict_iUnion_apply_eq_iSup
theorem restrict_map {f : α → β} (hf : Measurable f) {s : Set β} (hs : MeasurableSet s) :
(μ.map f).restrict s = (μ.restrict <| f ⁻¹' s).map f :=
ext fun t ht => by simp [*, hf ht]
#align measure_theory.measure.restrict_map MeasureTheory.Measure.restrict_map
theorem restrict_toMeasurable (h : μ s ≠ ∞) : μ.restrict (toMeasurable μ s) = μ.restrict s :=
ext fun t ht => by
rw [restrict_apply ht, restrict_apply ht, inter_comm, measure_toMeasurable_inter ht h,
inter_comm]
#align measure_theory.measure.restrict_to_measurable MeasureTheory.Measure.restrict_toMeasurable
theorem restrict_eq_self_of_ae_mem {_m0 : MeasurableSpace α} ⦃s : Set α⦄ ⦃μ : Measure α⦄
(hs : ∀ᵐ x ∂μ, x ∈ s) : μ.restrict s = μ :=
calc
μ.restrict s = μ.restrict univ := restrict_congr_set (eventuallyEq_univ.mpr hs)
_ = μ := restrict_univ
#align measure_theory.measure.restrict_eq_self_of_ae_mem MeasureTheory.Measure.restrict_eq_self_of_ae_mem
theorem restrict_congr_meas (hs : MeasurableSet s) :
μ.restrict s = ν.restrict s ↔ ∀ t ⊆ s, MeasurableSet t → μ t = ν t :=
⟨fun H t hts ht => by
rw [← inter_eq_self_of_subset_left hts, ← restrict_apply ht, H, restrict_apply ht], fun H =>
ext fun t ht => by
rw [restrict_apply ht, restrict_apply ht, H _ inter_subset_right (ht.inter hs)]⟩
#align measure_theory.measure.restrict_congr_meas MeasureTheory.Measure.restrict_congr_meas
theorem restrict_congr_mono (hs : s ⊆ t) (h : μ.restrict t = ν.restrict t) :
μ.restrict s = ν.restrict s := by
rw [← restrict_restrict_of_subset hs, h, restrict_restrict_of_subset hs]
#align measure_theory.measure.restrict_congr_mono MeasureTheory.Measure.restrict_congr_mono
| Mathlib/MeasureTheory/Measure/Restrict.lean | 360 | 382 | theorem restrict_union_congr :
μ.restrict (s ∪ t) = ν.restrict (s ∪ t) ↔
μ.restrict s = ν.restrict s ∧ μ.restrict t = ν.restrict t := by |
refine
⟨fun h =>
⟨restrict_congr_mono subset_union_left h,
restrict_congr_mono subset_union_right h⟩,
?_⟩
rintro ⟨hs, ht⟩
ext1 u hu
simp only [restrict_apply hu, inter_union_distrib_left]
rcases exists_measurable_superset₂ μ ν (u ∩ s) with ⟨US, hsub, hm, hμ, hν⟩
calc
μ (u ∩ s ∪ u ∩ t) = μ (US ∪ u ∩ t) :=
measure_union_congr_of_subset hsub hμ.le Subset.rfl le_rfl
_ = μ US + μ ((u ∩ t) \ US) := (measure_add_diff hm _).symm
_ = restrict μ s u + restrict μ t (u \ US) := by
simp only [restrict_apply, hu, hu.diff hm, hμ, ← inter_comm t, inter_diff_assoc]
_ = restrict ν s u + restrict ν t (u \ US) := by rw [hs, ht]
_ = ν US + ν ((u ∩ t) \ US) := by
simp only [restrict_apply, hu, hu.diff hm, hν, ← inter_comm t, inter_diff_assoc]
_ = ν (US ∪ u ∩ t) := measure_add_diff hm _
_ = ν (u ∩ s ∪ u ∩ t) := Eq.symm <| measure_union_congr_of_subset hsub hν.le Subset.rfl le_rfl
|
import Mathlib.Logic.Encodable.Lattice
import Mathlib.MeasureTheory.MeasurableSpace.Defs
#align_import measure_theory.pi_system from "leanprover-community/mathlib"@"98e83c3d541c77cdb7da20d79611a780ff8e7d90"
open MeasurableSpace Set
open scoped Classical
open MeasureTheory
def IsPiSystem {α} (C : Set (Set α)) : Prop :=
∀ᵉ (s ∈ C) (t ∈ C), (s ∩ t : Set α).Nonempty → s ∩ t ∈ C
#align is_pi_system IsPiSystem
theorem IsPiSystem.singleton {α} (S : Set α) : IsPiSystem ({S} : Set (Set α)) := by
intro s h_s t h_t _
rw [Set.mem_singleton_iff.1 h_s, Set.mem_singleton_iff.1 h_t, Set.inter_self,
Set.mem_singleton_iff]
#align is_pi_system.singleton IsPiSystem.singleton
theorem IsPiSystem.insert_empty {α} {S : Set (Set α)} (h_pi : IsPiSystem S) :
IsPiSystem (insert ∅ S) := by
intro s hs t ht hst
cases' hs with hs hs
· simp [hs]
· cases' ht with ht ht
· simp [ht]
· exact Set.mem_insert_of_mem _ (h_pi s hs t ht hst)
#align is_pi_system.insert_empty IsPiSystem.insert_empty
theorem IsPiSystem.insert_univ {α} {S : Set (Set α)} (h_pi : IsPiSystem S) :
IsPiSystem (insert Set.univ S) := by
intro s hs t ht hst
cases' hs with hs hs
· cases' ht with ht ht <;> simp [hs, ht]
· cases' ht with ht ht
· simp [hs, ht]
· exact Set.mem_insert_of_mem _ (h_pi s hs t ht hst)
#align is_pi_system.insert_univ IsPiSystem.insert_univ
| Mathlib/MeasureTheory/PiSystem.lean | 105 | 109 | theorem IsPiSystem.comap {α β} {S : Set (Set β)} (h_pi : IsPiSystem S) (f : α → β) :
IsPiSystem { s : Set α | ∃ t ∈ S, f ⁻¹' t = s } := by |
rintro _ ⟨s, hs_mem, rfl⟩ _ ⟨t, ht_mem, rfl⟩ hst
rw [← Set.preimage_inter] at hst ⊢
exact ⟨s ∩ t, h_pi s hs_mem t ht_mem (nonempty_of_nonempty_preimage hst), rfl⟩
|
import Mathlib.Algebra.Order.BigOperators.Group.Finset
import Mathlib.Data.Nat.Factors
import Mathlib.Order.Interval.Finset.Nat
#align_import number_theory.divisors from "leanprover-community/mathlib"@"e8638a0fcaf73e4500469f368ef9494e495099b3"
open scoped Classical
open Finset
namespace Nat
variable (n : ℕ)
def divisors : Finset ℕ :=
Finset.filter (fun x : ℕ => x ∣ n) (Finset.Ico 1 (n + 1))
#align nat.divisors Nat.divisors
def properDivisors : Finset ℕ :=
Finset.filter (fun x : ℕ => x ∣ n) (Finset.Ico 1 n)
#align nat.proper_divisors Nat.properDivisors
def divisorsAntidiagonal : Finset (ℕ × ℕ) :=
Finset.filter (fun x => x.fst * x.snd = n) (Ico 1 (n + 1) ×ˢ Ico 1 (n + 1))
#align nat.divisors_antidiagonal Nat.divisorsAntidiagonal
variable {n}
@[simp]
theorem filter_dvd_eq_divisors (h : n ≠ 0) : (Finset.range n.succ).filter (· ∣ n) = n.divisors := by
ext
simp only [divisors, mem_filter, mem_range, mem_Ico, and_congr_left_iff, iff_and_self]
exact fun ha _ => succ_le_iff.mpr (pos_of_dvd_of_pos ha h.bot_lt)
#align nat.filter_dvd_eq_divisors Nat.filter_dvd_eq_divisors
@[simp]
theorem filter_dvd_eq_properDivisors (h : n ≠ 0) :
(Finset.range n).filter (· ∣ n) = n.properDivisors := by
ext
simp only [properDivisors, mem_filter, mem_range, mem_Ico, and_congr_left_iff, iff_and_self]
exact fun ha _ => succ_le_iff.mpr (pos_of_dvd_of_pos ha h.bot_lt)
#align nat.filter_dvd_eq_proper_divisors Nat.filter_dvd_eq_properDivisors
theorem properDivisors.not_self_mem : ¬n ∈ properDivisors n := by simp [properDivisors]
#align nat.proper_divisors.not_self_mem Nat.properDivisors.not_self_mem
@[simp]
theorem mem_properDivisors {m : ℕ} : n ∈ properDivisors m ↔ n ∣ m ∧ n < m := by
rcases eq_or_ne m 0 with (rfl | hm); · simp [properDivisors]
simp only [and_comm, ← filter_dvd_eq_properDivisors hm, mem_filter, mem_range]
#align nat.mem_proper_divisors Nat.mem_properDivisors
theorem insert_self_properDivisors (h : n ≠ 0) : insert n (properDivisors n) = divisors n := by
rw [divisors, properDivisors, Ico_succ_right_eq_insert_Ico (one_le_iff_ne_zero.2 h),
Finset.filter_insert, if_pos (dvd_refl n)]
#align nat.insert_self_proper_divisors Nat.insert_self_properDivisors
theorem cons_self_properDivisors (h : n ≠ 0) :
cons n (properDivisors n) properDivisors.not_self_mem = divisors n := by
rw [cons_eq_insert, insert_self_properDivisors h]
#align nat.cons_self_proper_divisors Nat.cons_self_properDivisors
@[simp]
theorem mem_divisors {m : ℕ} : n ∈ divisors m ↔ n ∣ m ∧ m ≠ 0 := by
rcases eq_or_ne m 0 with (rfl | hm); · simp [divisors]
simp only [hm, Ne, not_false_iff, and_true_iff, ← filter_dvd_eq_divisors hm, mem_filter,
mem_range, and_iff_right_iff_imp, Nat.lt_succ_iff]
exact le_of_dvd hm.bot_lt
#align nat.mem_divisors Nat.mem_divisors
theorem one_mem_divisors : 1 ∈ divisors n ↔ n ≠ 0 := by simp
#align nat.one_mem_divisors Nat.one_mem_divisors
theorem mem_divisors_self (n : ℕ) (h : n ≠ 0) : n ∈ n.divisors :=
mem_divisors.2 ⟨dvd_rfl, h⟩
#align nat.mem_divisors_self Nat.mem_divisors_self
theorem dvd_of_mem_divisors {m : ℕ} (h : n ∈ divisors m) : n ∣ m := by
cases m
· apply dvd_zero
· simp [mem_divisors.1 h]
#align nat.dvd_of_mem_divisors Nat.dvd_of_mem_divisors
@[simp]
theorem mem_divisorsAntidiagonal {x : ℕ × ℕ} :
x ∈ divisorsAntidiagonal n ↔ x.fst * x.snd = n ∧ n ≠ 0 := by
simp only [divisorsAntidiagonal, Finset.mem_Ico, Ne, Finset.mem_filter, Finset.mem_product]
rw [and_comm]
apply and_congr_right
rintro rfl
constructor <;> intro h
· contrapose! h
simp [h]
· rw [Nat.lt_add_one_iff, Nat.lt_add_one_iff]
rw [mul_eq_zero, not_or] at h
simp only [succ_le_of_lt (Nat.pos_of_ne_zero h.1), succ_le_of_lt (Nat.pos_of_ne_zero h.2),
true_and_iff]
exact
⟨Nat.le_mul_of_pos_right _ (Nat.pos_of_ne_zero h.2),
Nat.le_mul_of_pos_left _ (Nat.pos_of_ne_zero h.1)⟩
#align nat.mem_divisors_antidiagonal Nat.mem_divisorsAntidiagonal
lemma ne_zero_of_mem_divisorsAntidiagonal {p : ℕ × ℕ} (hp : p ∈ n.divisorsAntidiagonal) :
p.1 ≠ 0 ∧ p.2 ≠ 0 := by
obtain ⟨hp₁, hp₂⟩ := Nat.mem_divisorsAntidiagonal.mp hp
exact mul_ne_zero_iff.mp (hp₁.symm ▸ hp₂)
lemma left_ne_zero_of_mem_divisorsAntidiagonal {p : ℕ × ℕ} (hp : p ∈ n.divisorsAntidiagonal) :
p.1 ≠ 0 :=
(ne_zero_of_mem_divisorsAntidiagonal hp).1
lemma right_ne_zero_of_mem_divisorsAntidiagonal {p : ℕ × ℕ} (hp : p ∈ n.divisorsAntidiagonal) :
p.2 ≠ 0 :=
(ne_zero_of_mem_divisorsAntidiagonal hp).2
theorem divisor_le {m : ℕ} : n ∈ divisors m → n ≤ m := by
cases' m with m
· simp
· simp only [mem_divisors, Nat.succ_ne_zero m, and_true_iff, Ne, not_false_iff]
exact Nat.le_of_dvd (Nat.succ_pos m)
#align nat.divisor_le Nat.divisor_le
theorem divisors_subset_of_dvd {m : ℕ} (hzero : n ≠ 0) (h : m ∣ n) : divisors m ⊆ divisors n :=
Finset.subset_iff.2 fun _x hx => Nat.mem_divisors.mpr ⟨(Nat.mem_divisors.mp hx).1.trans h, hzero⟩
#align nat.divisors_subset_of_dvd Nat.divisors_subset_of_dvd
theorem divisors_subset_properDivisors {m : ℕ} (hzero : n ≠ 0) (h : m ∣ n) (hdiff : m ≠ n) :
divisors m ⊆ properDivisors n := by
apply Finset.subset_iff.2
intro x hx
exact
Nat.mem_properDivisors.2
⟨(Nat.mem_divisors.1 hx).1.trans h,
lt_of_le_of_lt (divisor_le hx)
(lt_of_le_of_ne (divisor_le (Nat.mem_divisors.2 ⟨h, hzero⟩)) hdiff)⟩
#align nat.divisors_subset_proper_divisors Nat.divisors_subset_properDivisors
lemma divisors_filter_dvd_of_dvd {n m : ℕ} (hn : n ≠ 0) (hm : m ∣ n) :
(n.divisors.filter (· ∣ m)) = m.divisors := by
ext k
simp_rw [mem_filter, mem_divisors]
exact ⟨fun ⟨_, hkm⟩ ↦ ⟨hkm, ne_zero_of_dvd_ne_zero hn hm⟩, fun ⟨hk, _⟩ ↦ ⟨⟨hk.trans hm, hn⟩, hk⟩⟩
@[simp]
theorem divisors_zero : divisors 0 = ∅ := by
ext
simp
#align nat.divisors_zero Nat.divisors_zero
@[simp]
theorem properDivisors_zero : properDivisors 0 = ∅ := by
ext
simp
#align nat.proper_divisors_zero Nat.properDivisors_zero
@[simp]
lemma nonempty_divisors : (divisors n).Nonempty ↔ n ≠ 0 :=
⟨fun ⟨m, hm⟩ hn ↦ by simp [hn] at hm, fun hn ↦ ⟨1, one_mem_divisors.2 hn⟩⟩
@[simp]
lemma divisors_eq_empty : divisors n = ∅ ↔ n = 0 :=
not_nonempty_iff_eq_empty.symm.trans nonempty_divisors.not_left
theorem properDivisors_subset_divisors : properDivisors n ⊆ divisors n :=
filter_subset_filter _ <| Ico_subset_Ico_right n.le_succ
#align nat.proper_divisors_subset_divisors Nat.properDivisors_subset_divisors
@[simp]
theorem divisors_one : divisors 1 = {1} := by
ext
simp
#align nat.divisors_one Nat.divisors_one
@[simp]
theorem properDivisors_one : properDivisors 1 = ∅ := by rw [properDivisors, Ico_self, filter_empty]
#align nat.proper_divisors_one Nat.properDivisors_one
theorem pos_of_mem_divisors {m : ℕ} (h : m ∈ n.divisors) : 0 < m := by
cases m
· rw [mem_divisors, zero_dvd_iff (a := n)] at h
cases h.2 h.1
apply Nat.succ_pos
#align nat.pos_of_mem_divisors Nat.pos_of_mem_divisors
theorem pos_of_mem_properDivisors {m : ℕ} (h : m ∈ n.properDivisors) : 0 < m :=
pos_of_mem_divisors (properDivisors_subset_divisors h)
#align nat.pos_of_mem_proper_divisors Nat.pos_of_mem_properDivisors
theorem one_mem_properDivisors_iff_one_lt : 1 ∈ n.properDivisors ↔ 1 < n := by
rw [mem_properDivisors, and_iff_right (one_dvd _)]
#align nat.one_mem_proper_divisors_iff_one_lt Nat.one_mem_properDivisors_iff_one_lt
@[simp]
lemma sup_divisors_id (n : ℕ) : n.divisors.sup id = n := by
refine le_antisymm (Finset.sup_le fun _ ↦ divisor_le) ?_
rcases Decidable.eq_or_ne n 0 with rfl | hn
· apply zero_le
· exact Finset.le_sup (f := id) <| mem_divisors_self n hn
lemma one_lt_of_mem_properDivisors {m n : ℕ} (h : m ∈ n.properDivisors) : 1 < n :=
lt_of_le_of_lt (pos_of_mem_properDivisors h) (mem_properDivisors.1 h).2
lemma one_lt_div_of_mem_properDivisors {m n : ℕ} (h : m ∈ n.properDivisors) :
1 < n / m := by
obtain ⟨h_dvd, h_lt⟩ := mem_properDivisors.mp h
rwa [Nat.lt_div_iff_mul_lt h_dvd, mul_one]
lemma mem_properDivisors_iff_exists {m n : ℕ} (hn : n ≠ 0) :
m ∈ n.properDivisors ↔ ∃ k > 1, n = m * k := by
refine ⟨fun h ↦ ⟨n / m, one_lt_div_of_mem_properDivisors h, ?_⟩, ?_⟩
· exact (Nat.mul_div_cancel' (mem_properDivisors.mp h).1).symm
· rintro ⟨k, hk, rfl⟩
rw [mul_ne_zero_iff] at hn
exact mem_properDivisors.mpr ⟨⟨k, rfl⟩, lt_mul_of_one_lt_right (Nat.pos_of_ne_zero hn.1) hk⟩
@[simp]
lemma nonempty_properDivisors : n.properDivisors.Nonempty ↔ 1 < n :=
⟨fun ⟨_m, hm⟩ ↦ one_lt_of_mem_properDivisors hm, fun hn ↦
⟨1, one_mem_properDivisors_iff_one_lt.2 hn⟩⟩
@[simp]
lemma properDivisors_eq_empty : n.properDivisors = ∅ ↔ n ≤ 1 := by
rw [← not_nonempty_iff_eq_empty, nonempty_properDivisors, not_lt]
@[simp]
theorem divisorsAntidiagonal_zero : divisorsAntidiagonal 0 = ∅ := by
ext
simp
#align nat.divisors_antidiagonal_zero Nat.divisorsAntidiagonal_zero
@[simp]
theorem divisorsAntidiagonal_one : divisorsAntidiagonal 1 = {(1, 1)} := by
ext
simp [mul_eq_one, Prod.ext_iff]
#align nat.divisors_antidiagonal_one Nat.divisorsAntidiagonal_one
-- @[simp]
theorem swap_mem_divisorsAntidiagonal {x : ℕ × ℕ} :
x.swap ∈ divisorsAntidiagonal n ↔ x ∈ divisorsAntidiagonal n := by
rw [mem_divisorsAntidiagonal, mem_divisorsAntidiagonal, mul_comm, Prod.swap]
#align nat.swap_mem_divisors_antidiagonal Nat.swap_mem_divisorsAntidiagonal
-- Porting note: added below thm to replace the simp from the previous thm
@[simp]
theorem swap_mem_divisorsAntidiagonal_aux {x : ℕ × ℕ} :
x.snd * x.fst = n ∧ ¬n = 0 ↔ x ∈ divisorsAntidiagonal n := by
rw [mem_divisorsAntidiagonal, mul_comm]
theorem fst_mem_divisors_of_mem_antidiagonal {x : ℕ × ℕ} (h : x ∈ divisorsAntidiagonal n) :
x.fst ∈ divisors n := by
rw [mem_divisorsAntidiagonal] at h
simp [Dvd.intro _ h.1, h.2]
#align nat.fst_mem_divisors_of_mem_antidiagonal Nat.fst_mem_divisors_of_mem_antidiagonal
theorem snd_mem_divisors_of_mem_antidiagonal {x : ℕ × ℕ} (h : x ∈ divisorsAntidiagonal n) :
x.snd ∈ divisors n := by
rw [mem_divisorsAntidiagonal] at h
simp [Dvd.intro_left _ h.1, h.2]
#align nat.snd_mem_divisors_of_mem_antidiagonal Nat.snd_mem_divisors_of_mem_antidiagonal
@[simp]
theorem map_swap_divisorsAntidiagonal :
(divisorsAntidiagonal n).map (Equiv.prodComm _ _).toEmbedding = divisorsAntidiagonal n := by
rw [← coe_inj, coe_map, Equiv.coe_toEmbedding, Equiv.coe_prodComm,
Set.image_swap_eq_preimage_swap]
ext
exact swap_mem_divisorsAntidiagonal
#align nat.map_swap_divisors_antidiagonal Nat.map_swap_divisorsAntidiagonal
@[simp]
theorem image_fst_divisorsAntidiagonal : (divisorsAntidiagonal n).image Prod.fst = divisors n := by
ext
simp [Dvd.dvd, @eq_comm _ n (_ * _)]
#align nat.image_fst_divisors_antidiagonal Nat.image_fst_divisorsAntidiagonal
@[simp]
theorem image_snd_divisorsAntidiagonal : (divisorsAntidiagonal n).image Prod.snd = divisors n := by
rw [← map_swap_divisorsAntidiagonal, map_eq_image, image_image]
exact image_fst_divisorsAntidiagonal
#align nat.image_snd_divisors_antidiagonal Nat.image_snd_divisorsAntidiagonal
theorem map_div_right_divisors :
n.divisors.map ⟨fun d => (d, n / d), fun p₁ p₂ => congr_arg Prod.fst⟩ =
n.divisorsAntidiagonal := by
ext ⟨d, nd⟩
simp only [mem_map, mem_divisorsAntidiagonal, Function.Embedding.coeFn_mk, mem_divisors,
Prod.ext_iff, exists_prop, and_left_comm, exists_eq_left]
constructor
· rintro ⟨⟨⟨k, rfl⟩, hn⟩, rfl⟩
rw [Nat.mul_div_cancel_left _ (left_ne_zero_of_mul hn).bot_lt]
exact ⟨rfl, hn⟩
· rintro ⟨rfl, hn⟩
exact ⟨⟨dvd_mul_right _ _, hn⟩, Nat.mul_div_cancel_left _ (left_ne_zero_of_mul hn).bot_lt⟩
#align nat.map_div_right_divisors Nat.map_div_right_divisors
theorem map_div_left_divisors :
n.divisors.map ⟨fun d => (n / d, d), fun p₁ p₂ => congr_arg Prod.snd⟩ =
n.divisorsAntidiagonal := by
apply Finset.map_injective (Equiv.prodComm _ _).toEmbedding
ext
rw [map_swap_divisorsAntidiagonal, ← map_div_right_divisors, Finset.map_map]
simp
#align nat.map_div_left_divisors Nat.map_div_left_divisors
theorem sum_divisors_eq_sum_properDivisors_add_self :
∑ i ∈ divisors n, i = (∑ i ∈ properDivisors n, i) + n := by
rcases Decidable.eq_or_ne n 0 with (rfl | hn)
· simp
· rw [← cons_self_properDivisors hn, Finset.sum_cons, add_comm]
#align nat.sum_divisors_eq_sum_proper_divisors_add_self Nat.sum_divisors_eq_sum_properDivisors_add_self
def Perfect (n : ℕ) : Prop :=
∑ i ∈ properDivisors n, i = n ∧ 0 < n
#align nat.perfect Nat.Perfect
theorem perfect_iff_sum_properDivisors (h : 0 < n) : Perfect n ↔ ∑ i ∈ properDivisors n, i = n :=
and_iff_left h
#align nat.perfect_iff_sum_proper_divisors Nat.perfect_iff_sum_properDivisors
theorem perfect_iff_sum_divisors_eq_two_mul (h : 0 < n) :
Perfect n ↔ ∑ i ∈ divisors n, i = 2 * n := by
rw [perfect_iff_sum_properDivisors h, sum_divisors_eq_sum_properDivisors_add_self, two_mul]
constructor <;> intro h
· rw [h]
· apply add_right_cancel h
#align nat.perfect_iff_sum_divisors_eq_two_mul Nat.perfect_iff_sum_divisors_eq_two_mul
theorem mem_divisors_prime_pow {p : ℕ} (pp : p.Prime) (k : ℕ) {x : ℕ} :
x ∈ divisors (p ^ k) ↔ ∃ j ≤ k, x = p ^ j := by
rw [mem_divisors, Nat.dvd_prime_pow pp, and_iff_left (ne_of_gt (pow_pos pp.pos k))]
#align nat.mem_divisors_prime_pow Nat.mem_divisors_prime_pow
theorem Prime.divisors {p : ℕ} (pp : p.Prime) : divisors p = {1, p} := by
ext
rw [mem_divisors, dvd_prime pp, and_iff_left pp.ne_zero, Finset.mem_insert, Finset.mem_singleton]
#align nat.prime.divisors Nat.Prime.divisors
theorem Prime.properDivisors {p : ℕ} (pp : p.Prime) : properDivisors p = {1} := by
rw [← erase_insert properDivisors.not_self_mem, insert_self_properDivisors pp.ne_zero,
pp.divisors, pair_comm, erase_insert fun con => pp.ne_one (mem_singleton.1 con)]
#align nat.prime.proper_divisors Nat.Prime.properDivisors
theorem divisors_prime_pow {p : ℕ} (pp : p.Prime) (k : ℕ) :
divisors (p ^ k) = (Finset.range (k + 1)).map ⟨(p ^ ·), Nat.pow_right_injective pp.two_le⟩ := by
ext a
rw [mem_divisors_prime_pow pp]
simp [Nat.lt_succ, eq_comm]
#align nat.divisors_prime_pow Nat.divisors_prime_pow
theorem divisors_injective : Function.Injective divisors :=
Function.LeftInverse.injective sup_divisors_id
@[simp]
theorem divisors_inj {a b : ℕ} : a.divisors = b.divisors ↔ a = b :=
divisors_injective.eq_iff
theorem eq_properDivisors_of_subset_of_sum_eq_sum {s : Finset ℕ} (hsub : s ⊆ n.properDivisors) :
((∑ x ∈ s, x) = ∑ x ∈ n.properDivisors, x) → s = n.properDivisors := by
cases n
· rw [properDivisors_zero, subset_empty] at hsub
simp [hsub]
classical
rw [← sum_sdiff hsub]
intro h
apply Subset.antisymm hsub
rw [← sdiff_eq_empty_iff_subset]
contrapose h
rw [← Ne, ← nonempty_iff_ne_empty] at h
apply ne_of_lt
rw [← zero_add (∑ x ∈ s, x), ← add_assoc, add_zero]
apply add_lt_add_right
have hlt :=
sum_lt_sum_of_nonempty h fun x hx => pos_of_mem_properDivisors (sdiff_subset hx)
simp only [sum_const_zero] at hlt
apply hlt
#align nat.eq_proper_divisors_of_subset_of_sum_eq_sum Nat.eq_properDivisors_of_subset_of_sum_eq_sum
theorem sum_properDivisors_dvd (h : (∑ x ∈ n.properDivisors, x) ∣ n) :
∑ x ∈ n.properDivisors, x = 1 ∨ ∑ x ∈ n.properDivisors, x = n := by
cases' n with n
· simp
· cases' n with n
· simp at h
· rw [or_iff_not_imp_right]
intro ne_n
have hlt : ∑ x ∈ n.succ.succ.properDivisors, x < n.succ.succ :=
lt_of_le_of_ne (Nat.le_of_dvd (Nat.succ_pos _) h) ne_n
symm
rw [← mem_singleton, eq_properDivisors_of_subset_of_sum_eq_sum (singleton_subset_iff.2
(mem_properDivisors.2 ⟨h, hlt⟩)) (sum_singleton _ _), mem_properDivisors]
exact ⟨one_dvd _, Nat.succ_lt_succ (Nat.succ_pos _)⟩
#align nat.sum_proper_divisors_dvd Nat.sum_properDivisors_dvd
@[to_additive (attr := simp)]
| Mathlib/NumberTheory/Divisors.lean | 434 | 435 | theorem Prime.prod_properDivisors {α : Type*} [CommMonoid α] {p : ℕ} {f : ℕ → α} (h : p.Prime) :
∏ x ∈ p.properDivisors, f x = f 1 := by | simp [h.properDivisors]
|
import Mathlib.Algebra.Order.Group.Nat
import Mathlib.Data.List.Rotate
import Mathlib.GroupTheory.Perm.Support
#align_import group_theory.perm.list from "leanprover-community/mathlib"@"9003f28797c0664a49e4179487267c494477d853"
namespace List
variable {α β : Type*}
section FormPerm
variable [DecidableEq α] (l : List α)
open Equiv Equiv.Perm
def formPerm : Equiv.Perm α :=
(zipWith Equiv.swap l l.tail).prod
#align list.form_perm List.formPerm
@[simp]
theorem formPerm_nil : formPerm ([] : List α) = 1 :=
rfl
#align list.form_perm_nil List.formPerm_nil
@[simp]
theorem formPerm_singleton (x : α) : formPerm [x] = 1 :=
rfl
#align list.form_perm_singleton List.formPerm_singleton
@[simp]
theorem formPerm_cons_cons (x y : α) (l : List α) :
formPerm (x :: y :: l) = swap x y * formPerm (y :: l) :=
prod_cons
#align list.form_perm_cons_cons List.formPerm_cons_cons
theorem formPerm_pair (x y : α) : formPerm [x, y] = swap x y :=
rfl
#align list.form_perm_pair List.formPerm_pair
theorem mem_or_mem_of_zipWith_swap_prod_ne : ∀ {l l' : List α} {x : α},
(zipWith swap l l').prod x ≠ x → x ∈ l ∨ x ∈ l'
| [], _, _ => by simp
| _, [], _ => by simp
| a::l, b::l', x => fun hx ↦
if h : (zipWith swap l l').prod x = x then
(eq_or_eq_of_swap_apply_ne_self (by simpa [h] using hx)).imp
(by rintro rfl; exact .head _) (by rintro rfl; exact .head _)
else
(mem_or_mem_of_zipWith_swap_prod_ne h).imp (.tail _) (.tail _)
theorem zipWith_swap_prod_support' (l l' : List α) :
{ x | (zipWith swap l l').prod x ≠ x } ≤ l.toFinset ⊔ l'.toFinset := fun _ h ↦ by
simpa using mem_or_mem_of_zipWith_swap_prod_ne h
#align list.zip_with_swap_prod_support' List.zipWith_swap_prod_support'
theorem zipWith_swap_prod_support [Fintype α] (l l' : List α) :
(zipWith swap l l').prod.support ≤ l.toFinset ⊔ l'.toFinset := by
intro x hx
have hx' : x ∈ { x | (zipWith swap l l').prod x ≠ x } := by simpa using hx
simpa using zipWith_swap_prod_support' _ _ hx'
#align list.zip_with_swap_prod_support List.zipWith_swap_prod_support
theorem support_formPerm_le' : { x | formPerm l x ≠ x } ≤ l.toFinset := by
refine (zipWith_swap_prod_support' l l.tail).trans ?_
simpa [Finset.subset_iff] using tail_subset l
#align list.support_form_perm_le' List.support_formPerm_le'
theorem support_formPerm_le [Fintype α] : support (formPerm l) ≤ l.toFinset := by
intro x hx
have hx' : x ∈ { x | formPerm l x ≠ x } := by simpa using hx
simpa using support_formPerm_le' _ hx'
#align list.support_form_perm_le List.support_formPerm_le
variable {l} {x : α}
theorem mem_of_formPerm_apply_ne (h : l.formPerm x ≠ x) : x ∈ l := by
simpa [or_iff_left_of_imp mem_of_mem_tail] using mem_or_mem_of_zipWith_swap_prod_ne h
#align list.mem_of_form_perm_apply_ne List.mem_of_formPerm_apply_ne
theorem formPerm_apply_of_not_mem (h : x ∉ l) : formPerm l x = x :=
not_imp_comm.1 mem_of_formPerm_apply_ne h
#align list.form_perm_apply_of_not_mem List.formPerm_apply_of_not_mem
theorem formPerm_apply_mem_of_mem (h : x ∈ l) : formPerm l x ∈ l := by
cases' l with y l
· simp at h
induction' l with z l IH generalizing x y
· simpa using h
· by_cases hx : x ∈ z :: l
· rw [formPerm_cons_cons, mul_apply, swap_apply_def]
split_ifs
· simp [IH _ hx]
· simp
· simp [*]
· replace h : x = y := Or.resolve_right (mem_cons.1 h) hx
simp [formPerm_apply_of_not_mem hx, ← h]
#align list.form_perm_apply_mem_of_mem List.formPerm_apply_mem_of_mem
theorem mem_of_formPerm_apply_mem (h : l.formPerm x ∈ l) : x ∈ l := by
contrapose h
rwa [formPerm_apply_of_not_mem h]
#align list.mem_of_form_perm_apply_mem List.mem_of_formPerm_apply_mem
@[simp]
theorem formPerm_mem_iff_mem : l.formPerm x ∈ l ↔ x ∈ l :=
⟨l.mem_of_formPerm_apply_mem, l.formPerm_apply_mem_of_mem⟩
#align list.form_perm_mem_iff_mem List.formPerm_mem_iff_mem
@[simp]
theorem formPerm_cons_concat_apply_last (x y : α) (xs : List α) :
formPerm (x :: (xs ++ [y])) y = x := by
induction' xs with z xs IH generalizing x y
· simp
· simp [IH]
#align list.form_perm_cons_concat_apply_last List.formPerm_cons_concat_apply_last
@[simp]
theorem formPerm_apply_getLast (x : α) (xs : List α) :
formPerm (x :: xs) ((x :: xs).getLast (cons_ne_nil x xs)) = x := by
induction' xs using List.reverseRecOn with xs y _ generalizing x <;> simp
#align list.form_perm_apply_last List.formPerm_apply_getLast
@[simp]
theorem formPerm_apply_get_length (x : α) (xs : List α) :
formPerm (x :: xs) ((x :: xs).get (Fin.mk xs.length (by simp))) = x := by
rw [get_cons_length, formPerm_apply_getLast]; rfl;
set_option linter.deprecated false in
@[simp, deprecated formPerm_apply_get_length (since := "2024-05-30")]
theorem formPerm_apply_nthLe_length (x : α) (xs : List α) :
formPerm (x :: xs) ((x :: xs).nthLe xs.length (by simp)) = x := by
apply formPerm_apply_get_length
#align list.form_perm_apply_nth_le_length List.formPerm_apply_nthLe_length
theorem formPerm_apply_head (x y : α) (xs : List α) (h : Nodup (x :: y :: xs)) :
formPerm (x :: y :: xs) x = y := by simp [formPerm_apply_of_not_mem h.not_mem]
#align list.form_perm_apply_head List.formPerm_apply_head
theorem formPerm_apply_get_zero (l : List α) (h : Nodup l) (hl : 1 < l.length) :
formPerm l (l.get (Fin.mk 0 (by omega))) = l.get (Fin.mk 1 hl) := by
rcases l with (_ | ⟨x, _ | ⟨y, tl⟩⟩)
· simp at hl
· rw [get, get_singleton]; rfl;
· rw [get, formPerm_apply_head, get, get]
exact h
set_option linter.deprecated false in
@[deprecated formPerm_apply_get_zero (since := "2024-05-30")]
theorem formPerm_apply_nthLe_zero (l : List α) (h : Nodup l) (hl : 1 < l.length) :
formPerm l (l.nthLe 0 (by omega)) = l.nthLe 1 hl := by
apply formPerm_apply_get_zero _ h
#align list.form_perm_apply_nth_le_zero List.formPerm_apply_nthLe_zero
variable (l)
theorem formPerm_eq_head_iff_eq_getLast (x y : α) :
formPerm (y :: l) x = y ↔ x = getLast (y :: l) (cons_ne_nil _ _) :=
Iff.trans (by rw [formPerm_apply_getLast]) (formPerm (y :: l)).injective.eq_iff
#align list.form_perm_eq_head_iff_eq_last List.formPerm_eq_head_iff_eq_getLast
theorem formPerm_apply_lt_get (xs : List α) (h : Nodup xs) (n : ℕ) (hn : n + 1 < xs.length) :
formPerm xs (xs.get (Fin.mk n ((Nat.lt_succ_self n).trans hn))) =
xs.get (Fin.mk (n + 1) hn) := by
induction' n with n IH generalizing xs
· simpa using formPerm_apply_get_zero _ h _
· rcases xs with (_ | ⟨x, _ | ⟨y, l⟩⟩)
· simp at hn
· rw [formPerm_singleton, get_singleton, get_singleton]
rfl;
· specialize IH (y :: l) h.of_cons _
· simpa [Nat.succ_lt_succ_iff] using hn
simp only [swap_apply_eq_iff, coe_mul, formPerm_cons_cons, Function.comp]
simp only [get_cons_succ] at *
rw [← IH, swap_apply_of_ne_of_ne] <;>
· intro hx
rw [← hx, IH] at h
simp [get_mem] at h
set_option linter.deprecated false in
@[deprecated formPerm_apply_lt_get (since := "2024-05-30")]
theorem formPerm_apply_lt (xs : List α) (h : Nodup xs) (n : ℕ) (hn : n + 1 < xs.length) :
formPerm xs (xs.nthLe n ((Nat.lt_succ_self n).trans hn)) = xs.nthLe (n + 1) hn := by
apply formPerm_apply_lt_get _ h
#align list.form_perm_apply_lt List.formPerm_apply_lt
theorem formPerm_apply_get (xs : List α) (h : Nodup xs) (i : Fin xs.length) :
formPerm xs (xs.get i) =
xs.get ⟨((i.val + 1) % xs.length), (Nat.mod_lt _ (i.val.zero_le.trans_lt i.isLt))⟩ := by
let ⟨n, hn⟩ := i
cases' xs with x xs
· simp at hn
· have : n ≤ xs.length := by
refine Nat.le_of_lt_succ ?_
simpa using hn
rcases this.eq_or_lt with (rfl | hn')
· simp
· rw [formPerm_apply_lt_get (x :: xs) h _ (Nat.succ_lt_succ hn')]
congr
rw [Nat.mod_eq_of_lt]; simpa [Nat.succ_eq_add_one]
set_option linter.deprecated false in
@[deprecated formPerm_apply_get (since := "2024-04-23")]
theorem formPerm_apply_nthLe (xs : List α) (h : Nodup xs) (n : ℕ) (hn : n < xs.length) :
formPerm xs (xs.nthLe n hn) =
xs.nthLe ((n + 1) % xs.length) (Nat.mod_lt _ (n.zero_le.trans_lt hn)) := by
apply formPerm_apply_get _ h
#align list.form_perm_apply_nth_le List.formPerm_apply_nthLe
theorem support_formPerm_of_nodup' (l : List α) (h : Nodup l) (h' : ∀ x : α, l ≠ [x]) :
{ x | formPerm l x ≠ x } = l.toFinset := by
apply _root_.le_antisymm
· exact support_formPerm_le' l
· intro x hx
simp only [Finset.mem_coe, mem_toFinset] at hx
obtain ⟨⟨n, hn⟩, rfl⟩ := get_of_mem hx
rw [Set.mem_setOf_eq, formPerm_apply_get _ h]
intro H
rw [nodup_iff_injective_get, Function.Injective] at h
specialize h H
rcases (Nat.succ_le_of_lt hn).eq_or_lt with hn' | hn'
· simp only [← hn', Nat.mod_self] at h
refine' not_exists.mpr h' _
rw [← length_eq_one, ← hn', (Fin.mk.inj_iff.mp h).symm]
· simp [Nat.mod_eq_of_lt hn'] at h
#align list.support_form_perm_of_nodup' List.support_formPerm_of_nodup'
theorem support_formPerm_of_nodup [Fintype α] (l : List α) (h : Nodup l) (h' : ∀ x : α, l ≠ [x]) :
support (formPerm l) = l.toFinset := by
rw [← Finset.coe_inj]
convert support_formPerm_of_nodup' _ h h'
simp [Set.ext_iff]
#align list.support_form_perm_of_nodup List.support_formPerm_of_nodup
theorem formPerm_rotate_one (l : List α) (h : Nodup l) : formPerm (l.rotate 1) = formPerm l := by
have h' : Nodup (l.rotate 1) := by simpa using h
ext x
by_cases hx : x ∈ l.rotate 1
· obtain ⟨⟨k, hk⟩, rfl⟩ := get_of_mem hx
rw [formPerm_apply_get _ h', get_rotate l, get_rotate l, formPerm_apply_get _ h]
simp
· rw [formPerm_apply_of_not_mem hx, formPerm_apply_of_not_mem]
simpa using hx
#align list.form_perm_rotate_one List.formPerm_rotate_one
theorem formPerm_rotate (l : List α) (h : Nodup l) (n : ℕ) :
formPerm (l.rotate n) = formPerm l := by
induction' n with n hn
· simp
· rw [← rotate_rotate, formPerm_rotate_one, hn]
rwa [IsRotated.nodup_iff]
exact IsRotated.forall l n
#align list.form_perm_rotate List.formPerm_rotate
theorem formPerm_eq_of_isRotated {l l' : List α} (hd : Nodup l) (h : l ~r l') :
formPerm l = formPerm l' := by
obtain ⟨n, rfl⟩ := h
exact (formPerm_rotate l hd n).symm
#align list.form_perm_eq_of_is_rotated List.formPerm_eq_of_isRotated
theorem formPerm_append_pair : ∀ (l : List α) (a b : α),
formPerm (l ++ [a, b]) = formPerm (l ++ [a]) * swap a b
| [], _, _ => rfl
| [x], _, _ => rfl
| x::y::l, a, b => by
simpa [mul_assoc] using formPerm_append_pair (y::l) a b
theorem formPerm_reverse : ∀ l : List α, formPerm l.reverse = (formPerm l)⁻¹
| [] => rfl
| [_] => rfl
| a::b::l => by
simp [formPerm_append_pair, swap_comm, ← formPerm_reverse (b::l)]
#align list.form_perm_reverse List.formPerm_reverse
theorem formPerm_pow_apply_get (l : List α) (h : Nodup l) (n : ℕ) (i : Fin l.length) :
(formPerm l ^ n) (l.get i) =
l.get ⟨((i.val + n) % l.length), (Nat.mod_lt _ (i.val.zero_le.trans_lt i.isLt))⟩ := by
induction' n with n hn
· simp [Nat.mod_eq_of_lt i.isLt]
· simp [pow_succ', mul_apply, hn, formPerm_apply_get _ h, Nat.succ_eq_add_one, ← Nat.add_assoc]
set_option linter.deprecated false in
@[deprecated formPerm_pow_apply_get (since := "2024-04-23")]
theorem formPerm_pow_apply_nthLe (l : List α) (h : Nodup l) (n k : ℕ) (hk : k < l.length) :
(formPerm l ^ n) (l.nthLe k hk) =
l.nthLe ((k + n) % l.length) (Nat.mod_lt _ (k.zero_le.trans_lt hk)) :=
formPerm_pow_apply_get l h n ⟨k, hk⟩
#align list.form_perm_pow_apply_nth_le List.formPerm_pow_apply_nthLe
theorem formPerm_pow_apply_head (x : α) (l : List α) (h : Nodup (x :: l)) (n : ℕ) :
(formPerm (x :: l) ^ n) x =
(x :: l).get ⟨(n % (x :: l).length), (Nat.mod_lt _ (Nat.zero_lt_succ _))⟩ := by
convert formPerm_pow_apply_get _ h n ⟨0, Nat.succ_pos _⟩
simp
#align list.form_perm_pow_apply_head List.formPerm_pow_apply_head
| Mathlib/GroupTheory/Perm/List.lean | 328 | 362 | theorem formPerm_ext_iff {x y x' y' : α} {l l' : List α} (hd : Nodup (x :: y :: l))
(hd' : Nodup (x' :: y' :: l')) :
formPerm (x :: y :: l) = formPerm (x' :: y' :: l') ↔ (x :: y :: l) ~r (x' :: y' :: l') := by |
refine ⟨fun h => ?_, fun hr => formPerm_eq_of_isRotated hd hr⟩
rw [Equiv.Perm.ext_iff] at h
have hx : x' ∈ x :: y :: l := by
have : x' ∈ { z | formPerm (x :: y :: l) z ≠ z } := by
rw [Set.mem_setOf_eq, h x', formPerm_apply_head _ _ _ hd']
simp only [mem_cons, nodup_cons] at hd'
push_neg at hd'
exact hd'.left.left.symm
simpa using support_formPerm_le' _ this
obtain ⟨⟨n, hn⟩, hx'⟩ := get_of_mem hx
have hl : (x :: y :: l).length = (x' :: y' :: l').length := by
rw [← dedup_eq_self.mpr hd, ← dedup_eq_self.mpr hd', ← card_toFinset, ← card_toFinset]
refine congr_arg Finset.card ?_
rw [← Finset.coe_inj, ← support_formPerm_of_nodup' _ hd (by simp), ←
support_formPerm_of_nodup' _ hd' (by simp)]
simp only [h]
use n
apply List.ext_get
· rw [length_rotate, hl]
· intro k hk hk'
rw [get_rotate]
induction' k with k IH
· refine Eq.trans ?_ hx'
congr
simpa using hn
· conv => congr <;> · arg 2; (congr; (simp only [Fin.val_mk]; rw [← Nat.mod_eq_of_lt hk']))
rw [← formPerm_apply_get _ hd' ⟨k, k.lt_succ_self.trans hk'⟩,
← IH (k.lt_succ_self.trans hk), ← h, formPerm_apply_get _ hd]
congr 2
simp only [Fin.val_mk]
rw [hl, Nat.mod_eq_of_lt hk', add_right_comm]
apply Nat.add_mod
|
import Mathlib.Algebra.CharP.ExpChar
import Mathlib.Algebra.GeomSum
import Mathlib.Algebra.MvPolynomial.CommRing
import Mathlib.Algebra.MvPolynomial.Equiv
import Mathlib.RingTheory.Polynomial.Content
import Mathlib.RingTheory.UniqueFactorizationDomain
#align_import ring_theory.polynomial.basic from "leanprover-community/mathlib"@"da420a8c6dd5bdfb85c4ced85c34388f633bc6ff"
noncomputable section
open Polynomial
open Finset
universe u v w
variable {R : Type u} {S : Type*}
namespace Polynomial
section Semiring
variable [Semiring R]
instance instCharP (p : ℕ) [h : CharP R p] : CharP R[X] p :=
let ⟨h⟩ := h
⟨fun n => by rw [← map_natCast C, ← C_0, C_inj, h]⟩
instance instExpChar (p : ℕ) [h : ExpChar R p] : ExpChar R[X] p := by
cases h; exacts [ExpChar.zero, ExpChar.prime ‹_›]
variable (R)
def degreeLE (n : WithBot ℕ) : Submodule R R[X] :=
⨅ k : ℕ, ⨅ _ : ↑k > n, LinearMap.ker (lcoeff R k)
#align polynomial.degree_le Polynomial.degreeLE
def degreeLT (n : ℕ) : Submodule R R[X] :=
⨅ k : ℕ, ⨅ (_ : k ≥ n), LinearMap.ker (lcoeff R k)
#align polynomial.degree_lt Polynomial.degreeLT
variable {R}
theorem mem_degreeLE {n : WithBot ℕ} {f : R[X]} : f ∈ degreeLE R n ↔ degree f ≤ n := by
simp only [degreeLE, Submodule.mem_iInf, degree_le_iff_coeff_zero, LinearMap.mem_ker]; rfl
#align polynomial.mem_degree_le Polynomial.mem_degreeLE
@[mono]
theorem degreeLE_mono {m n : WithBot ℕ} (H : m ≤ n) : degreeLE R m ≤ degreeLE R n := fun _ hf =>
mem_degreeLE.2 (le_trans (mem_degreeLE.1 hf) H)
#align polynomial.degree_le_mono Polynomial.degreeLE_mono
theorem degreeLE_eq_span_X_pow [DecidableEq R] {n : ℕ} :
degreeLE R n = Submodule.span R ↑((Finset.range (n + 1)).image fun n => (X : R[X]) ^ n) := by
apply le_antisymm
· intro p hp
replace hp := mem_degreeLE.1 hp
rw [← Polynomial.sum_monomial_eq p, Polynomial.sum]
refine Submodule.sum_mem _ fun k hk => ?_
have := WithBot.coe_le_coe.1 (Finset.sup_le_iff.1 hp k hk)
rw [← C_mul_X_pow_eq_monomial, C_mul']
refine
Submodule.smul_mem _ _
(Submodule.subset_span <|
Finset.mem_coe.2 <|
Finset.mem_image.2 ⟨_, Finset.mem_range.2 (Nat.lt_succ_of_le this), rfl⟩)
rw [Submodule.span_le, Finset.coe_image, Set.image_subset_iff]
intro k hk
apply mem_degreeLE.2
exact
(degree_X_pow_le _).trans (WithBot.coe_le_coe.2 <| Nat.le_of_lt_succ <| Finset.mem_range.1 hk)
set_option linter.uppercaseLean3 false in
#align polynomial.degree_le_eq_span_X_pow Polynomial.degreeLE_eq_span_X_pow
theorem mem_degreeLT {n : ℕ} {f : R[X]} : f ∈ degreeLT R n ↔ degree f < n := by
rw [degreeLT, Submodule.mem_iInf]
conv_lhs => intro i; rw [Submodule.mem_iInf]
rw [degree, Finset.max_eq_sup_coe]
rw [Finset.sup_lt_iff ?_]
rotate_left
· apply WithBot.bot_lt_coe
conv_rhs =>
simp only [mem_support_iff]
intro b
rw [Nat.cast_withBot, WithBot.coe_lt_coe, lt_iff_not_le, Ne, not_imp_not]
rfl
#align polynomial.mem_degree_lt Polynomial.mem_degreeLT
@[mono]
theorem degreeLT_mono {m n : ℕ} (H : m ≤ n) : degreeLT R m ≤ degreeLT R n := fun _ hf =>
mem_degreeLT.2 (lt_of_lt_of_le (mem_degreeLT.1 hf) <| WithBot.coe_le_coe.2 H)
#align polynomial.degree_lt_mono Polynomial.degreeLT_mono
theorem degreeLT_eq_span_X_pow [DecidableEq R] {n : ℕ} :
degreeLT R n = Submodule.span R ↑((Finset.range n).image fun n => X ^ n : Finset R[X]) := by
apply le_antisymm
· intro p hp
replace hp := mem_degreeLT.1 hp
rw [← Polynomial.sum_monomial_eq p, Polynomial.sum]
refine Submodule.sum_mem _ fun k hk => ?_
have := WithBot.coe_lt_coe.1 ((Finset.sup_lt_iff <| WithBot.bot_lt_coe n).1 hp k hk)
rw [← C_mul_X_pow_eq_monomial, C_mul']
refine
Submodule.smul_mem _ _
(Submodule.subset_span <|
Finset.mem_coe.2 <| Finset.mem_image.2 ⟨_, Finset.mem_range.2 this, rfl⟩)
rw [Submodule.span_le, Finset.coe_image, Set.image_subset_iff]
intro k hk
apply mem_degreeLT.2
exact lt_of_le_of_lt (degree_X_pow_le _) (WithBot.coe_lt_coe.2 <| Finset.mem_range.1 hk)
set_option linter.uppercaseLean3 false in
#align polynomial.degree_lt_eq_span_X_pow Polynomial.degreeLT_eq_span_X_pow
def degreeLTEquiv (R) [Semiring R] (n : ℕ) : degreeLT R n ≃ₗ[R] Fin n → R where
toFun p n := (↑p : R[X]).coeff n
invFun f :=
⟨∑ i : Fin n, monomial i (f i),
(degreeLT R n).sum_mem fun i _ =>
mem_degreeLT.mpr
(lt_of_le_of_lt (degree_monomial_le i (f i)) (WithBot.coe_lt_coe.mpr i.is_lt))⟩
map_add' p q := by
ext
dsimp
rw [coeff_add]
map_smul' x p := by
ext
dsimp
rw [coeff_smul]
rfl
left_inv := by
rintro ⟨p, hp⟩
ext1
simp only [Submodule.coe_mk]
by_cases hp0 : p = 0
· subst hp0
simp only [coeff_zero, LinearMap.map_zero, Finset.sum_const_zero]
rw [mem_degreeLT, degree_eq_natDegree hp0, Nat.cast_lt] at hp
conv_rhs => rw [p.as_sum_range' n hp, ← Fin.sum_univ_eq_sum_range]
right_inv f := by
ext i
simp only [finset_sum_coeff, Submodule.coe_mk]
rw [Finset.sum_eq_single i, coeff_monomial, if_pos rfl]
· rintro j - hji
rw [coeff_monomial, if_neg]
rwa [← Fin.ext_iff]
· intro h
exact (h (Finset.mem_univ _)).elim
#align polynomial.degree_lt_equiv Polynomial.degreeLTEquiv
-- Porting note: removed @[simp] as simp can prove this
theorem degreeLTEquiv_eq_zero_iff_eq_zero {n : ℕ} {p : R[X]} (hp : p ∈ degreeLT R n) :
degreeLTEquiv _ _ ⟨p, hp⟩ = 0 ↔ p = 0 := by
rw [LinearEquiv.map_eq_zero_iff, Submodule.mk_eq_zero]
#align polynomial.degree_lt_equiv_eq_zero_iff_eq_zero Polynomial.degreeLTEquiv_eq_zero_iff_eq_zero
theorem eval_eq_sum_degreeLTEquiv {n : ℕ} {p : R[X]} (hp : p ∈ degreeLT R n) (x : R) :
p.eval x = ∑ i, degreeLTEquiv _ _ ⟨p, hp⟩ i * x ^ (i : ℕ) := by
simp_rw [eval_eq_sum]
exact (sum_fin _ (by simp_rw [zero_mul, forall_const]) (mem_degreeLT.mp hp)).symm
#align polynomial.eval_eq_sum_degree_lt_equiv Polynomial.eval_eq_sum_degreeLTEquiv
theorem degreeLT_succ_eq_degreeLE {n : ℕ} : degreeLT R (n + 1) = degreeLE R n := by
ext x
by_cases x_zero : x = 0
· simp_rw [x_zero, Submodule.zero_mem]
· rw [mem_degreeLT, mem_degreeLE, ← natDegree_lt_iff_degree_lt (by rwa [ne_eq]),
← natDegree_le_iff_degree_le, Nat.lt_succ]
| Mathlib/RingTheory/Polynomial/Basic.lean | 195 | 208 | theorem exists_degree_le_of_mem_span {s : Set R[X]} {p : R[X]}
(hs : s.Nonempty) (hp : p ∈ Submodule.span R s) :
∃ p' ∈ s, degree p ≤ degree p' := by |
by_contra! h
by_cases hp_zero : p = 0
· rw [hp_zero, degree_zero] at h
rcases hs with ⟨x, hx⟩
exact not_lt_bot (h x hx)
· have : p ∈ degreeLT R (natDegree p) := by
refine (Submodule.span_le.mpr fun p' p'_mem => ?_) hp
rw [SetLike.mem_coe, mem_degreeLT, Nat.cast_withBot]
exact lt_of_lt_of_le (h p' p'_mem) degree_le_natDegree
rwa [mem_degreeLT, Nat.cast_withBot, degree_eq_natDegree hp_zero,
Nat.cast_withBot, lt_self_iff_false] at this
|
import Mathlib.MeasureTheory.Function.LpSeminorm.Basic
import Mathlib.MeasureTheory.Integral.MeanInequalities
#align_import measure_theory.function.lp_seminorm from "leanprover-community/mathlib"@"c4015acc0a223449d44061e27ddac1835a3852b9"
open Filter
open scoped ENNReal Topology
namespace MeasureTheory
section BoundedSMul
variable {𝕜 α E F : Type*} {m : MeasurableSpace α} {μ : Measure α} [NormedRing 𝕜]
[NormedAddCommGroup E] [MulActionWithZero 𝕜 E] [BoundedSMul 𝕜 E]
[NormedAddCommGroup F] [MulActionWithZero 𝕜 F] [BoundedSMul 𝕜 F]
theorem snorm_smul_le_snorm_top_mul_snorm (p : ℝ≥0∞) {f : α → E} (hf : AEStronglyMeasurable f μ)
(φ : α → 𝕜) : snorm (φ • f) p μ ≤ snorm φ ∞ μ * snorm f p μ :=
(snorm_le_snorm_top_mul_snorm p φ hf (· • ·) (eventually_of_forall fun _ => nnnorm_smul_le _ _) :
_)
#align measure_theory.snorm_smul_le_snorm_top_mul_snorm MeasureTheory.snorm_smul_le_snorm_top_mul_snorm
theorem snorm_smul_le_snorm_mul_snorm_top (p : ℝ≥0∞) (f : α → E) {φ : α → 𝕜}
(hφ : AEStronglyMeasurable φ μ) : snorm (φ • f) p μ ≤ snorm φ p μ * snorm f ∞ μ :=
(snorm_le_snorm_mul_snorm_top p hφ f (· • ·) (eventually_of_forall fun _ => nnnorm_smul_le _ _) :
_)
#align measure_theory.snorm_smul_le_snorm_mul_snorm_top MeasureTheory.snorm_smul_le_snorm_mul_snorm_top
theorem snorm'_smul_le_mul_snorm' {p q r : ℝ} {f : α → E} (hf : AEStronglyMeasurable f μ)
{φ : α → 𝕜} (hφ : AEStronglyMeasurable φ μ) (hp0_lt : 0 < p) (hpq : p < q)
(hpqr : 1 / p = 1 / q + 1 / r) : snorm' (φ • f) p μ ≤ snorm' φ q μ * snorm' f r μ :=
snorm'_le_snorm'_mul_snorm' hφ hf (· • ·) (eventually_of_forall fun _ => nnnorm_smul_le _ _)
hp0_lt hpq hpqr
#align measure_theory.snorm'_smul_le_mul_snorm' MeasureTheory.snorm'_smul_le_mul_snorm'
theorem snorm_smul_le_mul_snorm {p q r : ℝ≥0∞} {f : α → E} (hf : AEStronglyMeasurable f μ)
{φ : α → 𝕜} (hφ : AEStronglyMeasurable φ μ) (hpqr : 1 / p = 1 / q + 1 / r) :
snorm (φ • f) p μ ≤ snorm φ q μ * snorm f r μ :=
(snorm_le_snorm_mul_snorm_of_nnnorm hφ hf (· • ·)
(eventually_of_forall fun _ => nnnorm_smul_le _ _) hpqr :
_)
#align measure_theory.snorm_smul_le_mul_snorm MeasureTheory.snorm_smul_le_mul_snorm
theorem Memℒp.smul {p q r : ℝ≥0∞} {f : α → E} {φ : α → 𝕜} (hf : Memℒp f r μ) (hφ : Memℒp φ q μ)
(hpqr : 1 / p = 1 / q + 1 / r) : Memℒp (φ • f) p μ :=
⟨hφ.1.smul hf.1,
(snorm_smul_le_mul_snorm hf.1 hφ.1 hpqr).trans_lt
(ENNReal.mul_lt_top hφ.snorm_ne_top hf.snorm_ne_top)⟩
#align measure_theory.mem_ℒp.smul MeasureTheory.Memℒp.smul
| Mathlib/MeasureTheory/Function/LpSeminorm/CompareExp.lean | 318 | 321 | theorem Memℒp.smul_of_top_right {p : ℝ≥0∞} {f : α → E} {φ : α → 𝕜} (hf : Memℒp f p μ)
(hφ : Memℒp φ ∞ μ) : Memℒp (φ • f) p μ := by |
apply hf.smul hφ
simp only [ENNReal.div_top, zero_add]
|
import Mathlib.Algebra.Polynomial.AlgebraMap
import Mathlib.Algebra.Polynomial.BigOperators
import Mathlib.Algebra.Polynomial.Degree.Lemmas
import Mathlib.Algebra.Polynomial.Div
#align_import data.polynomial.ring_division from "leanprover-community/mathlib"@"8efcf8022aac8e01df8d302dcebdbc25d6a886c8"
noncomputable section
open Polynomial
open Finset
namespace Polynomial
universe u v w z
variable {R : Type u} {S : Type v} {T : Type w} {a b : R} {n : ℕ}
section CommRing
variable [CommRing R] {p q : R[X]}
section
variable [Semiring S]
theorem natDegree_pos_of_aeval_root [Algebra R S] {p : R[X]} (hp : p ≠ 0) {z : S}
(hz : aeval z p = 0) (inj : ∀ x : R, algebraMap R S x = 0 → x = 0) : 0 < p.natDegree :=
natDegree_pos_of_eval₂_root hp (algebraMap R S) hz inj
#align polynomial.nat_degree_pos_of_aeval_root Polynomial.natDegree_pos_of_aeval_root
theorem degree_pos_of_aeval_root [Algebra R S] {p : R[X]} (hp : p ≠ 0) {z : S} (hz : aeval z p = 0)
(inj : ∀ x : R, algebraMap R S x = 0 → x = 0) : 0 < p.degree :=
natDegree_pos_iff_degree_pos.mp (natDegree_pos_of_aeval_root hp hz inj)
#align polynomial.degree_pos_of_aeval_root Polynomial.degree_pos_of_aeval_root
theorem modByMonic_eq_of_dvd_sub (hq : q.Monic) {p₁ p₂ : R[X]} (h : q ∣ p₁ - p₂) :
p₁ %ₘ q = p₂ %ₘ q := by
nontriviality R
obtain ⟨f, sub_eq⟩ := h
refine (div_modByMonic_unique (p₂ /ₘ q + f) _ hq ⟨?_, degree_modByMonic_lt _ hq⟩).2
rw [sub_eq_iff_eq_add.mp sub_eq, mul_add, ← add_assoc, modByMonic_add_div _ hq, add_comm]
#align polynomial.mod_by_monic_eq_of_dvd_sub Polynomial.modByMonic_eq_of_dvd_sub
theorem add_modByMonic (p₁ p₂ : R[X]) : (p₁ + p₂) %ₘ q = p₁ %ₘ q + p₂ %ₘ q := by
by_cases hq : q.Monic
· cases' subsingleton_or_nontrivial R with hR hR
· simp only [eq_iff_true_of_subsingleton]
· exact
(div_modByMonic_unique (p₁ /ₘ q + p₂ /ₘ q) _ hq
⟨by
rw [mul_add, add_left_comm, add_assoc, modByMonic_add_div _ hq, ← add_assoc,
add_comm (q * _), modByMonic_add_div _ hq],
(degree_add_le _ _).trans_lt
(max_lt (degree_modByMonic_lt _ hq) (degree_modByMonic_lt _ hq))⟩).2
· simp_rw [modByMonic_eq_of_not_monic _ hq]
#align polynomial.add_mod_by_monic Polynomial.add_modByMonic
| Mathlib/Algebra/Polynomial/RingDivision.lean | 72 | 80 | theorem smul_modByMonic (c : R) (p : R[X]) : c • p %ₘ q = c • (p %ₘ q) := by |
by_cases hq : q.Monic
· cases' subsingleton_or_nontrivial R with hR hR
· simp only [eq_iff_true_of_subsingleton]
· exact
(div_modByMonic_unique (c • (p /ₘ q)) (c • (p %ₘ q)) hq
⟨by rw [mul_smul_comm, ← smul_add, modByMonic_add_div p hq],
(degree_smul_le _ _).trans_lt (degree_modByMonic_lt _ hq)⟩).2
· simp_rw [modByMonic_eq_of_not_monic _ hq]
|
import Mathlib.Data.Set.Pointwise.Interval
import Mathlib.LinearAlgebra.AffineSpace.Basic
import Mathlib.LinearAlgebra.BilinearMap
import Mathlib.LinearAlgebra.Pi
import Mathlib.LinearAlgebra.Prod
#align_import linear_algebra.affine_space.affine_map from "leanprover-community/mathlib"@"bd1fc183335ea95a9519a1630bcf901fe9326d83"
open Affine
structure AffineMap (k : Type*) {V1 : Type*} (P1 : Type*) {V2 : Type*} (P2 : Type*) [Ring k]
[AddCommGroup V1] [Module k V1] [AffineSpace V1 P1] [AddCommGroup V2] [Module k V2]
[AffineSpace V2 P2] where
toFun : P1 → P2
linear : V1 →ₗ[k] V2
map_vadd' : ∀ (p : P1) (v : V1), toFun (v +ᵥ p) = linear v +ᵥ toFun p
#align affine_map AffineMap
notation:25 P1 " →ᵃ[" k:25 "] " P2:0 => AffineMap k P1 P2
instance AffineMap.instFunLike (k : Type*) {V1 : Type*} (P1 : Type*) {V2 : Type*} (P2 : Type*)
[Ring k] [AddCommGroup V1] [Module k V1] [AffineSpace V1 P1] [AddCommGroup V2] [Module k V2]
[AffineSpace V2 P2] : FunLike (P1 →ᵃ[k] P2) P1 P2 where
coe := AffineMap.toFun
coe_injective' := fun ⟨f, f_linear, f_add⟩ ⟨g, g_linear, g_add⟩ => fun (h : f = g) => by
cases' (AddTorsor.nonempty : Nonempty P1) with p
congr with v
apply vadd_right_cancel (f p)
erw [← f_add, h, ← g_add]
#align affine_map.fun_like AffineMap.instFunLike
instance AffineMap.hasCoeToFun (k : Type*) {V1 : Type*} (P1 : Type*) {V2 : Type*} (P2 : Type*)
[Ring k] [AddCommGroup V1] [Module k V1] [AffineSpace V1 P1] [AddCommGroup V2] [Module k V2]
[AffineSpace V2 P2] : CoeFun (P1 →ᵃ[k] P2) fun _ => P1 → P2 :=
DFunLike.hasCoeToFun
#align affine_map.has_coe_to_fun AffineMap.hasCoeToFun
namespace AffineMap
variable {k : Type*} {V1 : Type*} {P1 : Type*} {V2 : Type*} {P2 : Type*} {V3 : Type*}
{P3 : Type*} {V4 : Type*} {P4 : Type*} [Ring k] [AddCommGroup V1] [Module k V1]
[AffineSpace V1 P1] [AddCommGroup V2] [Module k V2] [AffineSpace V2 P2] [AddCommGroup V3]
[Module k V3] [AffineSpace V3 P3] [AddCommGroup V4] [Module k V4] [AffineSpace V4 P4]
@[simp]
theorem coe_mk (f : P1 → P2) (linear add) : ((mk f linear add : P1 →ᵃ[k] P2) : P1 → P2) = f :=
rfl
#align affine_map.coe_mk AffineMap.coe_mk
@[simp]
theorem toFun_eq_coe (f : P1 →ᵃ[k] P2) : f.toFun = ⇑f :=
rfl
#align affine_map.to_fun_eq_coe AffineMap.toFun_eq_coe
@[simp]
theorem map_vadd (f : P1 →ᵃ[k] P2) (p : P1) (v : V1) : f (v +ᵥ p) = f.linear v +ᵥ f p :=
f.map_vadd' p v
#align affine_map.map_vadd AffineMap.map_vadd
@[simp]
theorem linearMap_vsub (f : P1 →ᵃ[k] P2) (p1 p2 : P1) : f.linear (p1 -ᵥ p2) = f p1 -ᵥ f p2 := by
conv_rhs => rw [← vsub_vadd p1 p2, map_vadd, vadd_vsub]
#align affine_map.linear_map_vsub AffineMap.linearMap_vsub
@[ext]
theorem ext {f g : P1 →ᵃ[k] P2} (h : ∀ p, f p = g p) : f = g :=
DFunLike.ext _ _ h
#align affine_map.ext AffineMap.ext
theorem ext_iff {f g : P1 →ᵃ[k] P2} : f = g ↔ ∀ p, f p = g p :=
⟨fun h _ => h ▸ rfl, ext⟩
#align affine_map.ext_iff AffineMap.ext_iff
theorem coeFn_injective : @Function.Injective (P1 →ᵃ[k] P2) (P1 → P2) (⇑) :=
DFunLike.coe_injective
#align affine_map.coe_fn_injective AffineMap.coeFn_injective
protected theorem congr_arg (f : P1 →ᵃ[k] P2) {x y : P1} (h : x = y) : f x = f y :=
congr_arg _ h
#align affine_map.congr_arg AffineMap.congr_arg
protected theorem congr_fun {f g : P1 →ᵃ[k] P2} (h : f = g) (x : P1) : f x = g x :=
h ▸ rfl
#align affine_map.congr_fun AffineMap.congr_fun
theorem ext_linear {f g : P1 →ᵃ[k] P2} (h₁ : f.linear = g.linear) {p : P1} (h₂ : f p = g p) :
f = g := by
ext q
have hgl : g.linear (q -ᵥ p) = toFun g ((q -ᵥ p) +ᵥ q) -ᵥ toFun g q := by simp
have := f.map_vadd' q (q -ᵥ p)
rw [h₁, hgl, toFun_eq_coe, map_vadd, linearMap_vsub, h₂] at this
simp at this
exact this
theorem ext_linear_iff {f g : P1 →ᵃ[k] P2} : f = g ↔ (f.linear = g.linear) ∧ (∃ p, f p = g p) :=
⟨fun h ↦ ⟨congrArg _ h, by inhabit P1; exact default, by rw [h]⟩,
fun h ↦ Exists.casesOn h.2 fun _ hp ↦ ext_linear h.1 hp⟩
variable (k P1)
def const (p : P2) : P1 →ᵃ[k] P2 where
toFun := Function.const P1 p
linear := 0
map_vadd' _ _ :=
letI : AddAction V2 P2 := inferInstance
by simp
#align affine_map.const AffineMap.const
@[simp]
theorem coe_const (p : P2) : ⇑(const k P1 p) = Function.const P1 p :=
rfl
#align affine_map.coe_const AffineMap.coe_const
-- Porting note (#10756): new theorem
@[simp]
theorem const_apply (p : P2) (q : P1) : (const k P1 p) q = p := rfl
@[simp]
theorem const_linear (p : P2) : (const k P1 p).linear = 0 :=
rfl
#align affine_map.const_linear AffineMap.const_linear
variable {k P1}
theorem linear_eq_zero_iff_exists_const (f : P1 →ᵃ[k] P2) :
f.linear = 0 ↔ ∃ q, f = const k P1 q := by
refine ⟨fun h => ?_, fun h => ?_⟩
· use f (Classical.arbitrary P1)
ext
rw [coe_const, Function.const_apply, ← @vsub_eq_zero_iff_eq V2, ← f.linearMap_vsub, h,
LinearMap.zero_apply]
· rcases h with ⟨q, rfl⟩
exact const_linear k P1 q
#align affine_map.linear_eq_zero_iff_exists_const AffineMap.linear_eq_zero_iff_exists_const
instance nonempty : Nonempty (P1 →ᵃ[k] P2) :=
(AddTorsor.nonempty : Nonempty P2).map <| const k P1
#align affine_map.nonempty AffineMap.nonempty
def mk' (f : P1 → P2) (f' : V1 →ₗ[k] V2) (p : P1) (h : ∀ p' : P1, f p' = f' (p' -ᵥ p) +ᵥ f p) :
P1 →ᵃ[k] P2 where
toFun := f
linear := f'
map_vadd' p' v := by rw [h, h p', vadd_vsub_assoc, f'.map_add, vadd_vadd]
#align affine_map.mk' AffineMap.mk'
@[simp]
theorem coe_mk' (f : P1 → P2) (f' : V1 →ₗ[k] V2) (p h) : ⇑(mk' f f' p h) = f :=
rfl
#align affine_map.coe_mk' AffineMap.coe_mk'
@[simp]
theorem mk'_linear (f : P1 → P2) (f' : V1 →ₗ[k] V2) (p h) : (mk' f f' p h).linear = f' :=
rfl
#align affine_map.mk'_linear AffineMap.mk'_linear
namespace AffineMap
variable {R k V1 P1 V2 P2 V3 P3 : Type*}
section Ring
variable [Ring k] [AddCommGroup V1] [AffineSpace V1 P1] [AddCommGroup V2] [AffineSpace V2 P2]
variable [AddCommGroup V3] [AffineSpace V3 P3] [Module k V1] [Module k V2] [Module k V3]
section Pi
variable {ι : Type*} {φv φp : ι → Type*} [(i : ι) → AddCommGroup (φv i)]
[(i : ι) → Module k (φv i)] [(i : ι) → AffineSpace (φv i) (φp i)]
def pi (f : (i : ι) → (P1 →ᵃ[k] φp i)) : P1 →ᵃ[k] ((i : ι) → φp i) where
toFun m a := f a m
linear := LinearMap.pi (fun a ↦ (f a).linear)
map_vadd' _ _ := funext fun _ ↦ map_vadd _ _ _
--fp for when the image is a dependent AffineSpace φp i, fv for when the
--image is a Module φv i, f' for when the image isn't dependent.
variable (fp : (i : ι) → (P1 →ᵃ[k] φp i)) (fv : (i : ι) → (P1 →ᵃ[k] φv i))
(f' : ι → P1 →ᵃ[k] P2)
@[simp]
theorem pi_apply (c : P1) (i : ι) : pi fp c i = fp i c :=
rfl
theorem pi_comp (g : P3 →ᵃ[k] P1) : (pi fp).comp g = pi (fun i => (fp i).comp g) :=
rfl
theorem pi_eq_zero : pi fv = 0 ↔ ∀ i, fv i = 0 := by
simp only [AffineMap.ext_iff, Function.funext_iff, pi_apply]
exact forall_comm
theorem pi_zero : pi (fun _ ↦ 0 : (i : ι) → P1 →ᵃ[k] φv i) = 0 := by
ext; rfl
theorem proj_pi (i : ι) : (proj i).comp (pi fp) = fp i :=
ext fun _ => rfl
section CommRing
variable [CommRing k] [AddCommGroup V1] [AffineSpace V1 P1] [AddCommGroup V2]
variable [Module k V1] [Module k V2]
def homothety (c : P1) (r : k) : P1 →ᵃ[k] P1 :=
r • (id k P1 -ᵥ const k P1 c) +ᵥ const k P1 c
#align affine_map.homothety AffineMap.homothety
theorem homothety_def (c : P1) (r : k) :
homothety c r = r • (id k P1 -ᵥ const k P1 c) +ᵥ const k P1 c :=
rfl
#align affine_map.homothety_def AffineMap.homothety_def
theorem homothety_apply (c : P1) (r : k) (p : P1) : homothety c r p = r • (p -ᵥ c : V1) +ᵥ c :=
rfl
#align affine_map.homothety_apply AffineMap.homothety_apply
theorem homothety_eq_lineMap (c : P1) (r : k) (p : P1) : homothety c r p = lineMap c p r :=
rfl
#align affine_map.homothety_eq_line_map AffineMap.homothety_eq_lineMap
@[simp]
theorem homothety_one (c : P1) : homothety c (1 : k) = id k P1 := by
ext p
simp [homothety_apply]
#align affine_map.homothety_one AffineMap.homothety_one
@[simp]
theorem homothety_apply_same (c : P1) (r : k) : homothety c r c = c :=
lineMap_same_apply c r
#align affine_map.homothety_apply_same AffineMap.homothety_apply_same
theorem homothety_mul_apply (c : P1) (r₁ r₂ : k) (p : P1) :
homothety c (r₁ * r₂) p = homothety c r₁ (homothety c r₂ p) := by
simp only [homothety_apply, mul_smul, vadd_vsub]
#align affine_map.homothety_mul_apply AffineMap.homothety_mul_apply
theorem homothety_mul (c : P1) (r₁ r₂ : k) :
homothety c (r₁ * r₂) = (homothety c r₁).comp (homothety c r₂) :=
ext <| homothety_mul_apply c r₁ r₂
#align affine_map.homothety_mul AffineMap.homothety_mul
@[simp]
theorem homothety_zero (c : P1) : homothety c (0 : k) = const k P1 c := by
ext p
simp [homothety_apply]
#align affine_map.homothety_zero AffineMap.homothety_zero
@[simp]
| Mathlib/LinearAlgebra/AffineSpace/AffineMap.lean | 907 | 909 | theorem homothety_add (c : P1) (r₁ r₂ : k) :
homothety c (r₁ + r₂) = r₁ • (id k P1 -ᵥ const k P1 c) +ᵥ homothety c r₂ := by |
simp only [homothety_def, add_smul, vadd_vadd]
|
import Mathlib.Analysis.SpecialFunctions.ImproperIntegrals
import Mathlib.Analysis.Calculus.ParametricIntegral
import Mathlib.MeasureTheory.Measure.Haar.NormedSpace
#align_import analysis.mellin_transform from "leanprover-community/mathlib"@"917c3c072e487b3cccdbfeff17e75b40e45f66cb"
open MeasureTheory Set Filter Asymptotics TopologicalSpace
open Real
open Complex hiding exp log abs_of_nonneg
open scoped Topology
noncomputable section
section Defs
variable {E : Type*} [NormedAddCommGroup E] [NormedSpace ℂ E]
def MellinConvergent (f : ℝ → E) (s : ℂ) : Prop :=
IntegrableOn (fun t : ℝ => (t : ℂ) ^ (s - 1) • f t) (Ioi 0)
#align mellin_convergent MellinConvergent
theorem MellinConvergent.const_smul {f : ℝ → E} {s : ℂ} (hf : MellinConvergent f s) {𝕜 : Type*}
[NontriviallyNormedField 𝕜] [NormedSpace 𝕜 E] [SMulCommClass ℂ 𝕜 E] (c : 𝕜) :
MellinConvergent (fun t => c • f t) s := by
simpa only [MellinConvergent, smul_comm] using hf.smul c
#align mellin_convergent.const_smul MellinConvergent.const_smul
theorem MellinConvergent.cpow_smul {f : ℝ → E} {s a : ℂ} :
MellinConvergent (fun t => (t : ℂ) ^ a • f t) s ↔ MellinConvergent f (s + a) := by
refine integrableOn_congr_fun (fun t ht => ?_) measurableSet_Ioi
simp_rw [← sub_add_eq_add_sub, cpow_add _ _ (ofReal_ne_zero.2 <| ne_of_gt ht), mul_smul]
#align mellin_convergent.cpow_smul MellinConvergent.cpow_smul
nonrec theorem MellinConvergent.div_const {f : ℝ → ℂ} {s : ℂ} (hf : MellinConvergent f s) (a : ℂ) :
MellinConvergent (fun t => f t / a) s := by
simpa only [MellinConvergent, smul_eq_mul, ← mul_div_assoc] using hf.div_const a
#align mellin_convergent.div_const MellinConvergent.div_const
theorem MellinConvergent.comp_mul_left {f : ℝ → E} {s : ℂ} {a : ℝ} (ha : 0 < a) :
MellinConvergent (fun t => f (a * t)) s ↔ MellinConvergent f s := by
have := integrableOn_Ioi_comp_mul_left_iff (fun t : ℝ => (t : ℂ) ^ (s - 1) • f t) 0 ha
rw [mul_zero] at this
have h1 : EqOn (fun t : ℝ => (↑(a * t) : ℂ) ^ (s - 1) • f (a * t))
((a : ℂ) ^ (s - 1) • fun t : ℝ => (t : ℂ) ^ (s - 1) • f (a * t)) (Ioi 0) := fun t ht ↦ by
simp only [ofReal_mul, mul_cpow_ofReal_nonneg ha.le (le_of_lt ht), mul_smul, Pi.smul_apply]
have h2 : (a : ℂ) ^ (s - 1) ≠ 0 := by
rw [Ne, cpow_eq_zero_iff, not_and_or, ofReal_eq_zero]
exact Or.inl ha.ne'
rw [MellinConvergent, MellinConvergent, ← this, integrableOn_congr_fun h1 measurableSet_Ioi,
IntegrableOn, IntegrableOn, integrable_smul_iff h2]
#align mellin_convergent.comp_mul_left MellinConvergent.comp_mul_left
theorem MellinConvergent.comp_rpow {f : ℝ → E} {s : ℂ} {a : ℝ} (ha : a ≠ 0) :
MellinConvergent (fun t => f (t ^ a)) s ↔ MellinConvergent f (s / a) := by
refine Iff.trans ?_ (integrableOn_Ioi_comp_rpow_iff' _ ha)
rw [MellinConvergent]
refine integrableOn_congr_fun (fun t ht => ?_) measurableSet_Ioi
dsimp only [Pi.smul_apply]
rw [← Complex.coe_smul (t ^ (a - 1)), ← mul_smul, ← cpow_mul_ofReal_nonneg (le_of_lt ht),
ofReal_cpow (le_of_lt ht), ← cpow_add _ _ (ofReal_ne_zero.mpr (ne_of_gt ht)), ofReal_sub,
ofReal_one, mul_sub, mul_div_cancel₀ _ (ofReal_ne_zero.mpr ha), mul_one, add_comm, ←
add_sub_assoc, sub_add_cancel]
#align mellin_convergent.comp_rpow MellinConvergent.comp_rpow
def Complex.VerticalIntegrable (f : ℂ → E) (σ : ℝ) (μ : Measure ℝ := by volume_tac) : Prop :=
Integrable (fun (y : ℝ) ↦ f (σ + y * I)) μ
def mellin (f : ℝ → E) (s : ℂ) : E :=
∫ t : ℝ in Ioi 0, (t : ℂ) ^ (s - 1) • f t
#align mellin mellin
def mellinInv (σ : ℝ) (f : ℂ → E) (x : ℝ) : E :=
(1 / (2 * π)) • ∫ y : ℝ, (x : ℂ) ^ (-(σ + y * I)) • f (σ + y * I)
-- next few lemmas don't require convergence of the Mellin transform (they are just 0 = 0 otherwise)
theorem mellin_cpow_smul (f : ℝ → E) (s a : ℂ) :
mellin (fun t => (t : ℂ) ^ a • f t) s = mellin f (s + a) := by
refine setIntegral_congr measurableSet_Ioi fun t ht => ?_
simp_rw [← sub_add_eq_add_sub, cpow_add _ _ (ofReal_ne_zero.2 <| ne_of_gt ht), mul_smul]
#align mellin_cpow_smul mellin_cpow_smul
| Mathlib/Analysis/MellinTransform.lean | 112 | 114 | theorem mellin_const_smul (f : ℝ → E) (s : ℂ) {𝕜 : Type*} [NontriviallyNormedField 𝕜]
[NormedSpace 𝕜 E] [SMulCommClass ℂ 𝕜 E] (c : 𝕜) :
mellin (fun t => c • f t) s = c • mellin f s := by | simp only [mellin, smul_comm, integral_smul]
|
import Mathlib.RingTheory.DedekindDomain.Ideal
#align_import ring_theory.dedekind_domain.factorization from "leanprover-community/mathlib"@"2f588be38bb5bec02f218ba14f82fc82eb663f87"
noncomputable section
open scoped Classical nonZeroDivisors
open Set Function UniqueFactorizationMonoid IsDedekindDomain IsDedekindDomain.HeightOneSpectrum
Classical
variable {R : Type*} [CommRing R] {K : Type*} [Field K] [Algebra R K] [IsFractionRing R K]
variable [IsDedekindDomain R] (v : HeightOneSpectrum R)
def IsDedekindDomain.HeightOneSpectrum.maxPowDividing (I : Ideal R) : Ideal R :=
v.asIdeal ^ (Associates.mk v.asIdeal).count (Associates.mk I).factors
#align is_dedekind_domain.height_one_spectrum.max_pow_dividing IsDedekindDomain.HeightOneSpectrum.maxPowDividing
theorem Ideal.finite_factors {I : Ideal R} (hI : I ≠ 0) :
{v : HeightOneSpectrum R | v.asIdeal ∣ I}.Finite := by
rw [← Set.finite_coe_iff, Set.coe_setOf]
haveI h_fin := fintypeSubtypeDvd I hI
refine
Finite.of_injective (fun v => (⟨(v : HeightOneSpectrum R).asIdeal, v.2⟩ : { x // x ∣ I })) ?_
intro v w hvw
simp? at hvw says simp only [Subtype.mk.injEq] at hvw
exact Subtype.coe_injective ((HeightOneSpectrum.ext_iff (R := R) ↑v ↑w).mpr hvw)
#align ideal.finite_factors Ideal.finite_factors
theorem Associates.finite_factors {I : Ideal R} (hI : I ≠ 0) :
∀ᶠ v : HeightOneSpectrum R in Filter.cofinite,
((Associates.mk v.asIdeal).count (Associates.mk I).factors : ℤ) = 0 := by
have h_supp : {v : HeightOneSpectrum R | ¬((Associates.mk v.asIdeal).count
(Associates.mk I).factors : ℤ) = 0} = {v : HeightOneSpectrum R | v.asIdeal ∣ I} := by
ext v
simp_rw [Int.natCast_eq_zero]
exact Associates.count_ne_zero_iff_dvd hI v.irreducible
rw [Filter.eventually_cofinite, h_supp]
exact Ideal.finite_factors hI
#align associates.finite_factors Associates.finite_factors
namespace Ideal
theorem finite_mulSupport {I : Ideal R} (hI : I ≠ 0) :
(mulSupport fun v : HeightOneSpectrum R => v.maxPowDividing I).Finite :=
haveI h_subset : {v : HeightOneSpectrum R | v.maxPowDividing I ≠ 1} ⊆
{v : HeightOneSpectrum R |
((Associates.mk v.asIdeal).count (Associates.mk I).factors : ℤ) ≠ 0} := by
intro v hv h_zero
have hv' : v.maxPowDividing I = 1 := by
rw [IsDedekindDomain.HeightOneSpectrum.maxPowDividing, Int.natCast_eq_zero.mp h_zero,
pow_zero _]
exact hv hv'
Finite.subset (Filter.eventually_cofinite.mp (Associates.finite_factors hI)) h_subset
#align ideal.finite_mul_support Ideal.finite_mulSupport
theorem finite_mulSupport_coe {I : Ideal R} (hI : I ≠ 0) :
(mulSupport fun v : HeightOneSpectrum R => (v.asIdeal : FractionalIdeal R⁰ K) ^
((Associates.mk v.asIdeal).count (Associates.mk I).factors : ℤ)).Finite := by
rw [mulSupport]
simp_rw [Ne, zpow_natCast, ← FractionalIdeal.coeIdeal_pow, FractionalIdeal.coeIdeal_eq_one]
exact finite_mulSupport hI
#align ideal.finite_mul_support_coe Ideal.finite_mulSupport_coe
theorem finite_mulSupport_inv {I : Ideal R} (hI : I ≠ 0) :
(mulSupport fun v : HeightOneSpectrum R => (v.asIdeal : FractionalIdeal R⁰ K) ^
(-((Associates.mk v.asIdeal).count (Associates.mk I).factors : ℤ))).Finite := by
rw [mulSupport]
simp_rw [zpow_neg, Ne, inv_eq_one]
exact finite_mulSupport_coe hI
#align ideal.finite_mul_support_inv Ideal.finite_mulSupport_inv
| Mathlib/RingTheory/DedekindDomain/Factorization.lean | 131 | 144 | theorem finprod_not_dvd (I : Ideal R) (hI : I ≠ 0) :
¬v.asIdeal ^ ((Associates.mk v.asIdeal).count (Associates.mk I).factors + 1) ∣
∏ᶠ v : HeightOneSpectrum R, v.maxPowDividing I := by |
have hf := finite_mulSupport hI
have h_ne_zero : v.maxPowDividing I ≠ 0 := pow_ne_zero _ v.ne_bot
rw [← mul_finprod_cond_ne v hf, pow_add, pow_one, finprod_cond_ne _ _ hf]
intro h_contr
have hv_prime : Prime v.asIdeal := Ideal.prime_of_isPrime v.ne_bot v.isPrime
obtain ⟨w, hw, hvw'⟩ :=
Prime.exists_mem_finset_dvd hv_prime ((mul_dvd_mul_iff_left h_ne_zero).mp h_contr)
have hw_prime : Prime w.asIdeal := Ideal.prime_of_isPrime w.ne_bot w.isPrime
have hvw := Prime.dvd_of_dvd_pow hv_prime hvw'
rw [Prime.dvd_prime_iff_associated hv_prime hw_prime, associated_iff_eq] at hvw
exact (Finset.mem_erase.mp hw).1 (HeightOneSpectrum.ext w v (Eq.symm hvw))
|
import Mathlib.FieldTheory.SplittingField.Construction
import Mathlib.FieldTheory.IsAlgClosed.AlgebraicClosure
import Mathlib.FieldTheory.Separable
import Mathlib.FieldTheory.NormalClosure
import Mathlib.RingTheory.Polynomial.SeparableDegree
open scoped Classical Polynomial
open FiniteDimensional Polynomial IntermediateField Field
noncomputable section
universe u v w
variable (F : Type u) (E : Type v) [Field F] [Field E] [Algebra F E]
variable (K : Type w) [Field K] [Algebra F K]
namespace IntermediateField
@[simp]
theorem finSepDegree_bot : finSepDegree F (⊥ : IntermediateField F E) = 1 := by
rw [finSepDegree_eq_of_equiv _ _ _ (botEquiv F E), finSepDegree_self]
namespace Polynomial
variable {F E}
variable (f : F[X])
def natSepDegree : ℕ := (f.aroots f.SplittingField).toFinset.card
theorem natSepDegree_le_natDegree : f.natSepDegree ≤ f.natDegree := by
have := f.map (algebraMap F f.SplittingField) |>.card_roots'
rw [← aroots_def, natDegree_map] at this
exact (f.aroots f.SplittingField).toFinset_card_le.trans this
@[simp]
theorem natSepDegree_X_sub_C (x : F) : (X - C x).natSepDegree = 1 := by
simp only [natSepDegree, aroots_X_sub_C, Multiset.toFinset_singleton, Finset.card_singleton]
@[simp]
theorem natSepDegree_X : (X : F[X]).natSepDegree = 1 := by
simp only [natSepDegree, aroots_X, Multiset.toFinset_singleton, Finset.card_singleton]
theorem natSepDegree_eq_zero (h : f.natDegree = 0) : f.natSepDegree = 0 := by
linarith only [natSepDegree_le_natDegree f, h]
@[simp]
theorem natSepDegree_C (x : F) : (C x).natSepDegree = 0 := natSepDegree_eq_zero _ (natDegree_C _)
@[simp]
theorem natSepDegree_zero : (0 : F[X]).natSepDegree = 0 := by
rw [← C_0, natSepDegree_C]
@[simp]
theorem natSepDegree_one : (1 : F[X]).natSepDegree = 0 := by
rw [← C_1, natSepDegree_C]
theorem natSepDegree_ne_zero (h : f.natDegree ≠ 0) : f.natSepDegree ≠ 0 := by
rw [natSepDegree, ne_eq, Finset.card_eq_zero, ← ne_eq, ← Finset.nonempty_iff_ne_empty]
use rootOfSplits _ (SplittingField.splits f) (ne_of_apply_ne _ h)
rw [Multiset.mem_toFinset, mem_aroots]
exact ⟨ne_of_apply_ne _ h, map_rootOfSplits _ (SplittingField.splits f) (ne_of_apply_ne _ h)⟩
theorem natSepDegree_eq_zero_iff : f.natSepDegree = 0 ↔ f.natDegree = 0 :=
⟨(natSepDegree_ne_zero f).mtr, natSepDegree_eq_zero f⟩
theorem natSepDegree_ne_zero_iff : f.natSepDegree ≠ 0 ↔ f.natDegree ≠ 0 :=
Iff.not <| natSepDegree_eq_zero_iff f
theorem natSepDegree_eq_natDegree_iff (hf : f ≠ 0) :
f.natSepDegree = f.natDegree ↔ f.Separable := by
simp_rw [← card_rootSet_eq_natDegree_iff_of_splits hf (SplittingField.splits f),
rootSet_def, Finset.coe_sort_coe, Fintype.card_coe]
rfl
theorem natSepDegree_eq_natDegree_of_separable (h : f.Separable) :
f.natSepDegree = f.natDegree := (natSepDegree_eq_natDegree_iff f h.ne_zero).2 h
variable {f} in
theorem Separable.natSepDegree_eq_natDegree (h : f.Separable) :
f.natSepDegree = f.natDegree := natSepDegree_eq_natDegree_of_separable f h
theorem natSepDegree_eq_of_splits (h : f.Splits (algebraMap F E)) :
f.natSepDegree = (f.aroots E).toFinset.card := by
rw [aroots, ← (SplittingField.lift f h).comp_algebraMap, ← map_map,
roots_map _ ((splits_id_iff_splits _).mpr <| SplittingField.splits f),
Multiset.toFinset_map, Finset.card_image_of_injective _ (RingHom.injective _), natSepDegree]
variable (E) in
theorem natSepDegree_eq_of_isAlgClosed [IsAlgClosed E] :
f.natSepDegree = (f.aroots E).toFinset.card :=
natSepDegree_eq_of_splits f (IsAlgClosed.splits_codomain f)
variable (E) in
theorem natSepDegree_map : (f.map (algebraMap F E)).natSepDegree = f.natSepDegree := by
simp_rw [natSepDegree_eq_of_isAlgClosed (AlgebraicClosure E), aroots_def, map_map,
← IsScalarTower.algebraMap_eq]
@[simp]
theorem natSepDegree_C_mul {x : F} (hx : x ≠ 0) :
(C x * f).natSepDegree = f.natSepDegree := by
simp only [natSepDegree_eq_of_isAlgClosed (AlgebraicClosure F), aroots_C_mul _ hx]
@[simp]
theorem natSepDegree_smul_nonzero {x : F} (hx : x ≠ 0) :
(x • f).natSepDegree = f.natSepDegree := by
simp only [natSepDegree_eq_of_isAlgClosed (AlgebraicClosure F), aroots_smul_nonzero _ hx]
@[simp]
theorem natSepDegree_pow {n : ℕ} : (f ^ n).natSepDegree = if n = 0 then 0 else f.natSepDegree := by
simp only [natSepDegree_eq_of_isAlgClosed (AlgebraicClosure F), aroots_pow]
by_cases h : n = 0
· simp only [h, zero_smul, Multiset.toFinset_zero, Finset.card_empty, ite_true]
simp only [h, Multiset.toFinset_nsmul _ n h, ite_false]
theorem natSepDegree_pow_of_ne_zero {n : ℕ} (hn : n ≠ 0) :
(f ^ n).natSepDegree = f.natSepDegree := by simp_rw [natSepDegree_pow, hn, ite_false]
| Mathlib/FieldTheory/SeparableDegree.lean | 371 | 372 | theorem natSepDegree_X_pow {n : ℕ} : (X ^ n : F[X]).natSepDegree = if n = 0 then 0 else 1 := by |
simp only [natSepDegree_pow, natSepDegree_X]
|
import Mathlib.MeasureTheory.Measure.Typeclasses
import Mathlib.Analysis.Complex.Basic
#align_import measure_theory.measure.vector_measure from "leanprover-community/mathlib"@"70a4f2197832bceab57d7f41379b2592d1110570"
noncomputable section
open scoped Classical
open NNReal ENNReal MeasureTheory
namespace MeasureTheory
variable {α β : Type*} {m : MeasurableSpace α}
structure VectorMeasure (α : Type*) [MeasurableSpace α] (M : Type*) [AddCommMonoid M]
[TopologicalSpace M] where
measureOf' : Set α → M
empty' : measureOf' ∅ = 0
not_measurable' ⦃i : Set α⦄ : ¬MeasurableSet i → measureOf' i = 0
m_iUnion' ⦃f : ℕ → Set α⦄ : (∀ i, MeasurableSet (f i)) → Pairwise (Disjoint on f) →
HasSum (fun i => measureOf' (f i)) (measureOf' (⋃ i, f i))
#align measure_theory.vector_measure MeasureTheory.VectorMeasure
#align measure_theory.vector_measure.measure_of' MeasureTheory.VectorMeasure.measureOf'
#align measure_theory.vector_measure.empty' MeasureTheory.VectorMeasure.empty'
#align measure_theory.vector_measure.not_measurable' MeasureTheory.VectorMeasure.not_measurable'
#align measure_theory.vector_measure.m_Union' MeasureTheory.VectorMeasure.m_iUnion'
abbrev SignedMeasure (α : Type*) [MeasurableSpace α] :=
VectorMeasure α ℝ
#align measure_theory.signed_measure MeasureTheory.SignedMeasure
abbrev ComplexMeasure (α : Type*) [MeasurableSpace α] :=
VectorMeasure α ℂ
#align measure_theory.complex_measure MeasureTheory.ComplexMeasure
open Set MeasureTheory
namespace VectorMeasure
section
variable {M : Type*} [AddCommMonoid M] [TopologicalSpace M]
attribute [coe] VectorMeasure.measureOf'
instance instCoeFun : CoeFun (VectorMeasure α M) fun _ => Set α → M :=
⟨VectorMeasure.measureOf'⟩
#align measure_theory.vector_measure.has_coe_to_fun MeasureTheory.VectorMeasure.instCoeFun
initialize_simps_projections VectorMeasure (measureOf' → apply)
#noalign measure_theory.vector_measure.measure_of_eq_coe
@[simp]
theorem empty (v : VectorMeasure α M) : v ∅ = 0 :=
v.empty'
#align measure_theory.vector_measure.empty MeasureTheory.VectorMeasure.empty
theorem not_measurable (v : VectorMeasure α M) {i : Set α} (hi : ¬MeasurableSet i) : v i = 0 :=
v.not_measurable' hi
#align measure_theory.vector_measure.not_measurable MeasureTheory.VectorMeasure.not_measurable
theorem m_iUnion (v : VectorMeasure α M) {f : ℕ → Set α} (hf₁ : ∀ i, MeasurableSet (f i))
(hf₂ : Pairwise (Disjoint on f)) : HasSum (fun i => v (f i)) (v (⋃ i, f i)) :=
v.m_iUnion' hf₁ hf₂
#align measure_theory.vector_measure.m_Union MeasureTheory.VectorMeasure.m_iUnion
theorem of_disjoint_iUnion_nat [T2Space M] (v : VectorMeasure α M) {f : ℕ → Set α}
(hf₁ : ∀ i, MeasurableSet (f i)) (hf₂ : Pairwise (Disjoint on f)) :
v (⋃ i, f i) = ∑' i, v (f i) :=
(v.m_iUnion hf₁ hf₂).tsum_eq.symm
#align measure_theory.vector_measure.of_disjoint_Union_nat MeasureTheory.VectorMeasure.of_disjoint_iUnion_nat
theorem coe_injective : @Function.Injective (VectorMeasure α M) (Set α → M) (⇑) := fun v w h => by
cases v
cases w
congr
#align measure_theory.vector_measure.coe_injective MeasureTheory.VectorMeasure.coe_injective
theorem ext_iff' (v w : VectorMeasure α M) : v = w ↔ ∀ i : Set α, v i = w i := by
rw [← coe_injective.eq_iff, Function.funext_iff]
#align measure_theory.vector_measure.ext_iff' MeasureTheory.VectorMeasure.ext_iff'
theorem ext_iff (v w : VectorMeasure α M) : v = w ↔ ∀ i : Set α, MeasurableSet i → v i = w i := by
constructor
· rintro rfl _ _
rfl
· rw [ext_iff']
intro h i
by_cases hi : MeasurableSet i
· exact h i hi
· simp_rw [not_measurable _ hi]
#align measure_theory.vector_measure.ext_iff MeasureTheory.VectorMeasure.ext_iff
@[ext]
theorem ext {s t : VectorMeasure α M} (h : ∀ i : Set α, MeasurableSet i → s i = t i) : s = t :=
(ext_iff s t).2 h
#align measure_theory.vector_measure.ext MeasureTheory.VectorMeasure.ext
variable [T2Space M] {v : VectorMeasure α M} {f : ℕ → Set α}
theorem hasSum_of_disjoint_iUnion [Countable β] {f : β → Set α} (hf₁ : ∀ i, MeasurableSet (f i))
(hf₂ : Pairwise (Disjoint on f)) : HasSum (fun i => v (f i)) (v (⋃ i, f i)) := by
cases nonempty_encodable β
set g := fun i : ℕ => ⋃ (b : β) (_ : b ∈ Encodable.decode₂ β i), f b with hg
have hg₁ : ∀ i, MeasurableSet (g i) :=
fun _ => MeasurableSet.iUnion fun b => MeasurableSet.iUnion fun _ => hf₁ b
have hg₂ : Pairwise (Disjoint on g) := Encodable.iUnion_decode₂_disjoint_on hf₂
have := v.of_disjoint_iUnion_nat hg₁ hg₂
rw [hg, Encodable.iUnion_decode₂] at this
have hg₃ : (fun i : β => v (f i)) = fun i => v (g (Encodable.encode i)) := by
ext x
rw [hg]
simp only
congr
ext y
simp only [exists_prop, Set.mem_iUnion, Option.mem_def]
constructor
· intro hy
exact ⟨x, (Encodable.decode₂_is_partial_inv _ _).2 rfl, hy⟩
· rintro ⟨b, hb₁, hb₂⟩
rw [Encodable.decode₂_is_partial_inv _ _] at hb₁
rwa [← Encodable.encode_injective hb₁]
rw [Summable.hasSum_iff, this, ← tsum_iUnion_decode₂]
· exact v.empty
· rw [hg₃]
change Summable ((fun i => v (g i)) ∘ Encodable.encode)
rw [Function.Injective.summable_iff Encodable.encode_injective]
· exact (v.m_iUnion hg₁ hg₂).summable
· intro x hx
convert v.empty
simp only [g, Set.iUnion_eq_empty, Option.mem_def, not_exists, Set.mem_range] at hx ⊢
intro i hi
exact False.elim ((hx i) ((Encodable.decode₂_is_partial_inv _ _).1 hi))
#align measure_theory.vector_measure.has_sum_of_disjoint_Union MeasureTheory.VectorMeasure.hasSum_of_disjoint_iUnion
theorem of_disjoint_iUnion [Countable β] {f : β → Set α} (hf₁ : ∀ i, MeasurableSet (f i))
(hf₂ : Pairwise (Disjoint on f)) : v (⋃ i, f i) = ∑' i, v (f i) :=
(hasSum_of_disjoint_iUnion hf₁ hf₂).tsum_eq.symm
#align measure_theory.vector_measure.of_disjoint_Union MeasureTheory.VectorMeasure.of_disjoint_iUnion
theorem of_union {A B : Set α} (h : Disjoint A B) (hA : MeasurableSet A) (hB : MeasurableSet B) :
v (A ∪ B) = v A + v B := by
rw [Set.union_eq_iUnion, of_disjoint_iUnion, tsum_fintype, Fintype.sum_bool, cond, cond]
exacts [fun b => Bool.casesOn b hB hA, pairwise_disjoint_on_bool.2 h]
#align measure_theory.vector_measure.of_union MeasureTheory.VectorMeasure.of_union
theorem of_add_of_diff {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B) (h : A ⊆ B) :
v A + v (B \ A) = v B := by
rw [← of_union (@Set.disjoint_sdiff_right _ A B) hA (hB.diff hA), Set.union_diff_cancel h]
#align measure_theory.vector_measure.of_add_of_diff MeasureTheory.VectorMeasure.of_add_of_diff
theorem of_diff {M : Type*} [AddCommGroup M] [TopologicalSpace M] [T2Space M]
{v : VectorMeasure α M} {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B)
(h : A ⊆ B) : v (B \ A) = v B - v A := by
rw [← of_add_of_diff hA hB h, add_sub_cancel_left]
#align measure_theory.vector_measure.of_diff MeasureTheory.VectorMeasure.of_diff
theorem of_diff_of_diff_eq_zero {A B : Set α} (hA : MeasurableSet A) (hB : MeasurableSet B)
(h' : v (B \ A) = 0) : v (A \ B) + v B = v A := by
symm
calc
v A = v (A \ B ∪ A ∩ B) := by simp only [Set.diff_union_inter]
_ = v (A \ B) + v (A ∩ B) := by
rw [of_union]
· rw [disjoint_comm]
exact Set.disjoint_of_subset_left A.inter_subset_right disjoint_sdiff_self_right
· exact hA.diff hB
· exact hA.inter hB
_ = v (A \ B) + v (A ∩ B ∪ B \ A) := by
rw [of_union, h', add_zero]
· exact Set.disjoint_of_subset_left A.inter_subset_left disjoint_sdiff_self_right
· exact hA.inter hB
· exact hB.diff hA
_ = v (A \ B) + v B := by rw [Set.union_comm, Set.inter_comm, Set.diff_union_inter]
#align measure_theory.vector_measure.of_diff_of_diff_eq_zero MeasureTheory.VectorMeasure.of_diff_of_diff_eq_zero
theorem of_iUnion_nonneg {M : Type*} [TopologicalSpace M] [OrderedAddCommMonoid M]
[OrderClosedTopology M] {v : VectorMeasure α M} (hf₁ : ∀ i, MeasurableSet (f i))
(hf₂ : Pairwise (Disjoint on f)) (hf₃ : ∀ i, 0 ≤ v (f i)) : 0 ≤ v (⋃ i, f i) :=
(v.of_disjoint_iUnion_nat hf₁ hf₂).symm ▸ tsum_nonneg hf₃
#align measure_theory.vector_measure.of_Union_nonneg MeasureTheory.VectorMeasure.of_iUnion_nonneg
theorem of_iUnion_nonpos {M : Type*} [TopologicalSpace M] [OrderedAddCommMonoid M]
[OrderClosedTopology M] {v : VectorMeasure α M} (hf₁ : ∀ i, MeasurableSet (f i))
(hf₂ : Pairwise (Disjoint on f)) (hf₃ : ∀ i, v (f i) ≤ 0) : v (⋃ i, f i) ≤ 0 :=
(v.of_disjoint_iUnion_nat hf₁ hf₂).symm ▸ tsum_nonpos hf₃
#align measure_theory.vector_measure.of_Union_nonpos MeasureTheory.VectorMeasure.of_iUnion_nonpos
theorem of_nonneg_disjoint_union_eq_zero {s : SignedMeasure α} {A B : Set α} (h : Disjoint A B)
(hA₁ : MeasurableSet A) (hB₁ : MeasurableSet B) (hA₂ : 0 ≤ s A) (hB₂ : 0 ≤ s B)
(hAB : s (A ∪ B) = 0) : s A = 0 := by
rw [of_union h hA₁ hB₁] at hAB
linarith
#align measure_theory.vector_measure.of_nonneg_disjoint_union_eq_zero MeasureTheory.VectorMeasure.of_nonneg_disjoint_union_eq_zero
theorem of_nonpos_disjoint_union_eq_zero {s : SignedMeasure α} {A B : Set α} (h : Disjoint A B)
(hA₁ : MeasurableSet A) (hB₁ : MeasurableSet B) (hA₂ : s A ≤ 0) (hB₂ : s B ≤ 0)
(hAB : s (A ∪ B) = 0) : s A = 0 := by
rw [of_union h hA₁ hB₁] at hAB
linarith
#align measure_theory.vector_measure.of_nonpos_disjoint_union_eq_zero MeasureTheory.VectorMeasure.of_nonpos_disjoint_union_eq_zero
end
namespace VectorMeasure
open Measure
section
def ennrealToMeasure {_ : MeasurableSpace α} (v : VectorMeasure α ℝ≥0∞) : Measure α :=
ofMeasurable (fun s _ => v s) v.empty fun _ hf₁ hf₂ => v.of_disjoint_iUnion_nat hf₁ hf₂
#align measure_theory.vector_measure.ennreal_to_measure MeasureTheory.VectorMeasure.ennrealToMeasure
theorem ennrealToMeasure_apply {m : MeasurableSpace α} {v : VectorMeasure α ℝ≥0∞} {s : Set α}
(hs : MeasurableSet s) : ennrealToMeasure v s = v s := by
rw [ennrealToMeasure, ofMeasurable_apply _ hs]
#align measure_theory.vector_measure.ennreal_to_measure_apply MeasureTheory.VectorMeasure.ennrealToMeasure_apply
@[simp]
theorem _root_.MeasureTheory.Measure.toENNRealVectorMeasure_ennrealToMeasure
(μ : VectorMeasure α ℝ≥0∞) :
toENNRealVectorMeasure (ennrealToMeasure μ) = μ := ext fun s hs => by
rw [toENNRealVectorMeasure_apply_measurable hs, ennrealToMeasure_apply hs]
@[simp]
theorem ennrealToMeasure_toENNRealVectorMeasure (μ : Measure α) :
ennrealToMeasure (toENNRealVectorMeasure μ) = μ := Measure.ext fun s hs => by
rw [ennrealToMeasure_apply hs, toENNRealVectorMeasure_apply_measurable hs]
@[simps]
def equivMeasure [MeasurableSpace α] : VectorMeasure α ℝ≥0∞ ≃ Measure α where
toFun := ennrealToMeasure
invFun := toENNRealVectorMeasure
left_inv := toENNRealVectorMeasure_ennrealToMeasure
right_inv := ennrealToMeasure_toENNRealVectorMeasure
#align measure_theory.vector_measure.equiv_measure MeasureTheory.VectorMeasure.equivMeasure
end
section
variable [MeasurableSpace α] [MeasurableSpace β]
variable {M : Type*} [AddCommMonoid M] [TopologicalSpace M]
variable (v : VectorMeasure α M)
def map (v : VectorMeasure α M) (f : α → β) : VectorMeasure β M :=
if hf : Measurable f then
{ measureOf' := fun s => if MeasurableSet s then v (f ⁻¹' s) else 0
empty' := by simp
not_measurable' := fun i hi => if_neg hi
m_iUnion' := by
intro g hg₁ hg₂
simp only
convert v.m_iUnion (fun i => hf (hg₁ i)) fun i j hij => (hg₂ hij).preimage _
· rw [if_pos (hg₁ _)]
· rw [Set.preimage_iUnion, if_pos (MeasurableSet.iUnion hg₁)] }
else 0
#align measure_theory.vector_measure.map MeasureTheory.VectorMeasure.map
theorem map_not_measurable {f : α → β} (hf : ¬Measurable f) : v.map f = 0 :=
dif_neg hf
#align measure_theory.vector_measure.map_not_measurable MeasureTheory.VectorMeasure.map_not_measurable
theorem map_apply {f : α → β} (hf : Measurable f) {s : Set β} (hs : MeasurableSet s) :
v.map f s = v (f ⁻¹' s) := by
rw [map, dif_pos hf]
exact if_pos hs
#align measure_theory.vector_measure.map_apply MeasureTheory.VectorMeasure.map_apply
@[simp]
theorem map_id : v.map id = v :=
ext fun i hi => by rw [map_apply v measurable_id hi, Set.preimage_id]
#align measure_theory.vector_measure.map_id MeasureTheory.VectorMeasure.map_id
@[simp]
theorem map_zero (f : α → β) : (0 : VectorMeasure α M).map f = 0 := by
by_cases hf : Measurable f
· ext i hi
rw [map_apply _ hf hi, zero_apply, zero_apply]
· exact dif_neg hf
#align measure_theory.vector_measure.map_zero MeasureTheory.VectorMeasure.map_zero
section
variable {N : Type*} [AddCommMonoid N] [TopologicalSpace N]
def mapRange (v : VectorMeasure α M) (f : M →+ N) (hf : Continuous f) : VectorMeasure α N where
measureOf' s := f (v s)
empty' := by simp only; rw [empty, AddMonoidHom.map_zero]
not_measurable' i hi := by simp only; rw [not_measurable v hi, AddMonoidHom.map_zero]
m_iUnion' g hg₁ hg₂ := HasSum.map (v.m_iUnion hg₁ hg₂) f hf
#align measure_theory.vector_measure.map_range MeasureTheory.VectorMeasure.mapRange
@[simp]
theorem mapRange_apply {f : M →+ N} (hf : Continuous f) {s : Set α} : v.mapRange f hf s = f (v s) :=
rfl
#align measure_theory.vector_measure.map_range_apply MeasureTheory.VectorMeasure.mapRange_apply
@[simp]
theorem mapRange_id : v.mapRange (AddMonoidHom.id M) continuous_id = v := by
ext
rfl
#align measure_theory.vector_measure.map_range_id MeasureTheory.VectorMeasure.mapRange_id
@[simp]
| Mathlib/MeasureTheory/Measure/VectorMeasure.lean | 615 | 618 | theorem mapRange_zero {f : M →+ N} (hf : Continuous f) :
mapRange (0 : VectorMeasure α M) f hf = 0 := by |
ext
simp
|
import Mathlib.Algebra.Group.Submonoid.Membership
import Mathlib.Algebra.Module.Defs
import Mathlib.Algebra.Ring.Action.Subobjects
import Mathlib.Algebra.Ring.Equiv
import Mathlib.Algebra.Ring.Prod
import Mathlib.Data.Set.Finite
import Mathlib.GroupTheory.Submonoid.Centralizer
import Mathlib.RingTheory.NonUnitalSubsemiring.Basic
#align_import ring_theory.subsemiring.basic from "leanprover-community/mathlib"@"b915e9392ecb2a861e1e766f0e1df6ac481188ca"
universe u v w
variable {R : Type u} {S : Type v} {T : Type w} [NonAssocSemiring R] (M : Submonoid R)
namespace RingHom
variable (g : S →+* T) (f : R →+* S)
def rangeS : Subsemiring S :=
((⊤ : Subsemiring R).map f).copy (Set.range f) Set.image_univ.symm
#align ring_hom.srange RingHom.rangeS
@[simp]
theorem coe_rangeS : (f.rangeS : Set S) = Set.range f :=
rfl
#align ring_hom.coe_srange RingHom.coe_rangeS
@[simp]
theorem mem_rangeS {f : R →+* S} {y : S} : y ∈ f.rangeS ↔ ∃ x, f x = y :=
Iff.rfl
#align ring_hom.mem_srange RingHom.mem_rangeS
| Mathlib/Algebra/Ring/Subsemiring/Basic.lean | 526 | 528 | theorem rangeS_eq_map (f : R →+* S) : f.rangeS = (⊤ : Subsemiring R).map f := by |
ext
simp
|
import Mathlib.Data.Set.Image
import Mathlib.Data.SProd
#align_import data.set.prod from "leanprover-community/mathlib"@"48fb5b5280e7c81672afc9524185ae994553ebf4"
open Function
namespace Set
section Prod
variable {α β γ δ : Type*} {s s₁ s₂ : Set α} {t t₁ t₂ : Set β} {a : α} {b : β}
theorem Subsingleton.prod (hs : s.Subsingleton) (ht : t.Subsingleton) :
(s ×ˢ t).Subsingleton := fun _x hx _y hy ↦
Prod.ext (hs hx.1 hy.1) (ht hx.2 hy.2)
noncomputable instance decidableMemProd [DecidablePred (· ∈ s)] [DecidablePred (· ∈ t)] :
DecidablePred (· ∈ s ×ˢ t) := fun _ => And.decidable
#align set.decidable_mem_prod Set.decidableMemProd
@[gcongr]
theorem prod_mono (hs : s₁ ⊆ s₂) (ht : t₁ ⊆ t₂) : s₁ ×ˢ t₁ ⊆ s₂ ×ˢ t₂ :=
fun _ ⟨h₁, h₂⟩ => ⟨hs h₁, ht h₂⟩
#align set.prod_mono Set.prod_mono
@[gcongr]
theorem prod_mono_left (hs : s₁ ⊆ s₂) : s₁ ×ˢ t ⊆ s₂ ×ˢ t :=
prod_mono hs Subset.rfl
#align set.prod_mono_left Set.prod_mono_left
@[gcongr]
theorem prod_mono_right (ht : t₁ ⊆ t₂) : s ×ˢ t₁ ⊆ s ×ˢ t₂ :=
prod_mono Subset.rfl ht
#align set.prod_mono_right Set.prod_mono_right
@[simp]
theorem prod_self_subset_prod_self : s₁ ×ˢ s₁ ⊆ s₂ ×ˢ s₂ ↔ s₁ ⊆ s₂ :=
⟨fun h _ hx => (h (mk_mem_prod hx hx)).1, fun h _ hx => ⟨h hx.1, h hx.2⟩⟩
#align set.prod_self_subset_prod_self Set.prod_self_subset_prod_self
@[simp]
theorem prod_self_ssubset_prod_self : s₁ ×ˢ s₁ ⊂ s₂ ×ˢ s₂ ↔ s₁ ⊂ s₂ :=
and_congr prod_self_subset_prod_self <| not_congr prod_self_subset_prod_self
#align set.prod_self_ssubset_prod_self Set.prod_self_ssubset_prod_self
theorem prod_subset_iff {P : Set (α × β)} : s ×ˢ t ⊆ P ↔ ∀ x ∈ s, ∀ y ∈ t, (x, y) ∈ P :=
⟨fun h _ hx _ hy => h (mk_mem_prod hx hy), fun h ⟨_, _⟩ hp => h _ hp.1 _ hp.2⟩
#align set.prod_subset_iff Set.prod_subset_iff
theorem forall_prod_set {p : α × β → Prop} : (∀ x ∈ s ×ˢ t, p x) ↔ ∀ x ∈ s, ∀ y ∈ t, p (x, y) :=
prod_subset_iff
#align set.forall_prod_set Set.forall_prod_set
theorem exists_prod_set {p : α × β → Prop} : (∃ x ∈ s ×ˢ t, p x) ↔ ∃ x ∈ s, ∃ y ∈ t, p (x, y) := by
simp [and_assoc]
#align set.exists_prod_set Set.exists_prod_set
@[simp]
theorem prod_empty : s ×ˢ (∅ : Set β) = ∅ := by
ext
exact and_false_iff _
#align set.prod_empty Set.prod_empty
@[simp]
theorem empty_prod : (∅ : Set α) ×ˢ t = ∅ := by
ext
exact false_and_iff _
#align set.empty_prod Set.empty_prod
@[simp, mfld_simps]
theorem univ_prod_univ : @univ α ×ˢ @univ β = univ := by
ext
exact true_and_iff _
#align set.univ_prod_univ Set.univ_prod_univ
theorem univ_prod {t : Set β} : (univ : Set α) ×ˢ t = Prod.snd ⁻¹' t := by simp [prod_eq]
#align set.univ_prod Set.univ_prod
theorem prod_univ {s : Set α} : s ×ˢ (univ : Set β) = Prod.fst ⁻¹' s := by simp [prod_eq]
#align set.prod_univ Set.prod_univ
@[simp] lemma prod_eq_univ [Nonempty α] [Nonempty β] : s ×ˢ t = univ ↔ s = univ ∧ t = univ := by
simp [eq_univ_iff_forall, forall_and]
@[simp]
theorem singleton_prod : ({a} : Set α) ×ˢ t = Prod.mk a '' t := by
ext ⟨x, y⟩
simp [and_left_comm, eq_comm]
#align set.singleton_prod Set.singleton_prod
@[simp]
theorem prod_singleton : s ×ˢ ({b} : Set β) = (fun a => (a, b)) '' s := by
ext ⟨x, y⟩
simp [and_left_comm, eq_comm]
#align set.prod_singleton Set.prod_singleton
| Mathlib/Data/Set/Prod.lean | 122 | 122 | theorem singleton_prod_singleton : ({a} : Set α) ×ˢ ({b} : Set β) = {(a, b)} := by | simp
|
import Mathlib.Algebra.Homology.ExactSequence
import Mathlib.CategoryTheory.Abelian.Refinements
#align_import category_theory.abelian.diagram_lemmas.four from "leanprover-community/mathlib"@"d34cbcf6c94953e965448c933cd9cc485115ebbd"
namespace CategoryTheory
open Category Limits Preadditive
namespace Abelian
variable {C : Type*} [Category C] [Abelian C]
open ComposableArrows
section Three
variable {R₁ R₂ : ComposableArrows C 2} (φ : R₁ ⟶ R₂)
attribute [local simp] Precomp.map
theorem mono_of_epi_of_epi_mono' (hR₁ : R₁.map' 0 2 = 0) (hR₁' : Epi (R₁.map' 1 2))
(hR₂ : R₂.Exact) (h₀ : Epi (app' φ 0)) (h₁ : Mono (app' φ 1)) :
Mono (app' φ 2) := by
let ψ : mk₃ (R₁.map' 0 1) (R₁.map' 1 2) (0 : _ ⟶ R₁.obj' 0) ⟶
mk₃ (R₂.map' 0 1) (R₂.map' 1 2) (0 : _ ⟶ R₁.obj' 0) := homMk₃ (app' φ 0) (app' φ 1)
(app' φ 2) (𝟙 _) (naturality' φ 0 1) (naturality' φ 1 2) (by simp)
refine mono_of_epi_of_mono_of_mono' ψ ?_ (exact₂_mk _ (by simp) ?_)
(hR₂.exact 0).exact_toComposableArrows h₀ h₁ (by dsimp [ψ]; infer_instance)
· dsimp
rw [← Functor.map_comp]
exact hR₁
· rw [ShortComplex.exact_iff_epi _ (by simp)]
exact hR₁'
theorem mono_of_epi_of_epi_of_mono (hR₁ : R₁.Exact) (hR₂ : R₂.Exact)
(hR₁' : Epi (R₁.map' 1 2)) (h₀ : Epi (app' φ 0)) (h₁ : Mono (app' φ 1)) :
Mono (app' φ 2) :=
mono_of_epi_of_epi_mono' φ (by simpa only [map'_comp R₁ 0 1 2] using hR₁.toIsComplex.zero 0)
hR₁' hR₂ h₀ h₁
theorem epi_of_mono_of_epi_of_mono' (hR₁ : R₁.Exact) (hR₂ : R₂.map' 0 2 = 0)
(hR₂' : Mono (R₂.map' 0 1)) (h₀ : Epi (app' φ 1)) (h₁ : Mono (app' φ 2)) :
Epi (app' φ 0) := by
let ψ : mk₃ (0 : R₁.obj' 0 ⟶ _) (R₁.map' 0 1) (R₁.map' 1 2) ⟶
mk₃ (0 : R₁.obj' 0 ⟶ _) (R₂.map' 0 1) (R₂.map' 1 2) := homMk₃ (𝟙 _) (app' φ 0) (app' φ 1)
(app' φ 2) (by simp) (naturality' φ 0 1) (naturality' φ 1 2)
refine epi_of_epi_of_epi_of_mono' ψ (hR₁.exact 0).exact_toComposableArrows
(exact₂_mk _ (by simp) ?_) ?_ (by dsimp [ψ]; infer_instance) h₀ h₁
· rw [ShortComplex.exact_iff_mono _ (by simp)]
exact hR₂'
· dsimp
rw [← Functor.map_comp]
exact hR₂
theorem epi_of_mono_of_epi_of_mono (hR₁ : R₁.Exact) (hR₂ : R₂.Exact)
(hR₂' : Mono (R₂.map' 0 1)) (h₀ : Epi (app' φ 1)) (h₁ : Mono (app' φ 2)) :
Epi (app' φ 0) :=
epi_of_mono_of_epi_of_mono' φ hR₁
(by simpa only [map'_comp R₂ 0 1 2] using hR₂.toIsComplex.zero 0) hR₂' h₀ h₁
| Mathlib/CategoryTheory/Abelian/DiagramLemmas/Four.lean | 207 | 219 | theorem mono_of_mono_of_mono_of_mono (hR₁ : R₁.Exact)
(hR₂' : Mono (R₂.map' 0 1))
(h₀ : Mono (app' φ 0))
(h₁ : Mono (app' φ 2)) :
Mono (app' φ 1) := by |
let ψ : mk₃ (0 : R₁.obj' 0 ⟶ _) (R₁.map' 0 1) (R₁.map' 1 2) ⟶
mk₃ (0 : R₁.obj' 0 ⟶ _) (R₂.map' 0 1) (R₂.map' 1 2) := homMk₃ (𝟙 _) (app' φ 0) (app' φ 1)
(app' φ 2) (by simp) (naturality' φ 0 1) (naturality' φ 1 2)
refine mono_of_epi_of_mono_of_mono' ψ (by simp)
(hR₁.exact 0).exact_toComposableArrows
(exact₂_mk _ (by simp) ?_) (by dsimp [ψ]; infer_instance) h₀ h₁
rw [ShortComplex.exact_iff_mono _ (by simp)]
exact hR₂'
|
import Mathlib.Algebra.Field.Defs
import Mathlib.Algebra.GroupWithZero.Units.Lemmas
import Mathlib.Algebra.Ring.Commute
import Mathlib.Algebra.Ring.Invertible
import Mathlib.Order.Synonym
#align_import algebra.field.basic from "leanprover-community/mathlib"@"05101c3df9d9cfe9430edc205860c79b6d660102"
open Function OrderDual Set
universe u
variable {α β K : Type*}
section DivisionSemiring
variable [DivisionSemiring α] {a b c d : α}
theorem add_div (a b c : α) : (a + b) / c = a / c + b / c := by simp_rw [div_eq_mul_inv, add_mul]
#align add_div add_div
@[field_simps]
theorem div_add_div_same (a b c : α) : a / c + b / c = (a + b) / c :=
(add_div _ _ _).symm
#align div_add_div_same div_add_div_same
theorem same_add_div (h : b ≠ 0) : (b + a) / b = 1 + a / b := by rw [← div_self h, add_div]
#align same_add_div same_add_div
theorem div_add_same (h : b ≠ 0) : (a + b) / b = a / b + 1 := by rw [← div_self h, add_div]
#align div_add_same div_add_same
theorem one_add_div (h : b ≠ 0) : 1 + a / b = (b + a) / b :=
(same_add_div h).symm
#align one_add_div one_add_div
theorem div_add_one (h : b ≠ 0) : a / b + 1 = (a + b) / b :=
(div_add_same h).symm
#align div_add_one div_add_one
theorem inv_add_inv' (ha : a ≠ 0) (hb : b ≠ 0) :
a⁻¹ + b⁻¹ = a⁻¹ * (a + b) * b⁻¹ :=
let _ := invertibleOfNonzero ha; let _ := invertibleOfNonzero hb; invOf_add_invOf a b
| Mathlib/Algebra/Field/Basic.lean | 56 | 58 | theorem one_div_mul_add_mul_one_div_eq_one_div_add_one_div (ha : a ≠ 0) (hb : b ≠ 0) :
1 / a * (a + b) * (1 / b) = 1 / a + 1 / b := by |
simpa only [one_div] using (inv_add_inv' ha hb).symm
|
import Mathlib.GroupTheory.CoprodI
import Mathlib.GroupTheory.Coprod.Basic
import Mathlib.GroupTheory.QuotientGroup
import Mathlib.GroupTheory.Complement
namespace Monoid
open CoprodI Subgroup Coprod Function List
variable {ι : Type*} {G : ι → Type*} {H : Type*} {K : Type*} [Monoid K]
def PushoutI.con [∀ i, Monoid (G i)] [Monoid H] (φ : ∀ i, H →* G i) :
Con (Coprod (CoprodI G) H) :=
conGen (fun x y : Coprod (CoprodI G) H =>
∃ i x', x = inl (of (φ i x')) ∧ y = inr x')
def PushoutI [∀ i, Monoid (G i)] [Monoid H] (φ : ∀ i, H →* G i) : Type _ :=
(PushoutI.con φ).Quotient
namespace PushoutI
variable [∀ i, Group (G i)] [Group H] {φ : ∀ i, H →* G i}
instance : Group (PushoutI φ) :=
{ Con.group (PushoutI.con φ) with
toMonoid := PushoutI.monoid }
open NormalWord
theorem of_injective (hφ : ∀ i, Function.Injective (φ i)) (i : ι) :
Function.Injective (of (φ := φ) i) := by
rcases transversal_nonempty φ hφ with ⟨d⟩
let _ := Classical.decEq ι
let _ := fun i => Classical.decEq (G i)
refine Function.Injective.of_comp
(f := ((· • ·) : PushoutI φ → NormalWord d → NormalWord d)) ?_
intros _ _ h
exact eq_of_smul_eq_smul (fun w : NormalWord d =>
by simp_all [Function.funext_iff, of_smul_eq_smul])
theorem base_injective (hφ : ∀ i, Function.Injective (φ i)) :
Function.Injective (base φ) := by
rcases transversal_nonempty φ hφ with ⟨d⟩
let _ := Classical.decEq ι
let _ := fun i => Classical.decEq (G i)
refine Function.Injective.of_comp
(f := ((· • ·) : PushoutI φ → NormalWord d → NormalWord d)) ?_
intros _ _ h
exact eq_of_smul_eq_smul (fun w : NormalWord d =>
by simp_all [Function.funext_iff, base_smul_eq_smul])
section Reduced
open NormalWord
variable (φ)
def Reduced (w : Word G) : Prop :=
∀ g, g ∈ w.toList → g.2 ∉ (φ g.1).range
variable {φ}
| Mathlib/GroupTheory/PushoutI.lean | 626 | 638 | theorem Reduced.exists_normalWord_prod_eq (d : Transversal φ) {w : Word G} (hw : Reduced φ w) :
∃ w' : NormalWord d, w'.prod = ofCoprodI w.prod ∧
w'.toList.map Sigma.fst = w.toList.map Sigma.fst := by |
classical
induction w using Word.consRecOn with
| h_empty => exact ⟨empty, by simp, rfl⟩
| h_cons i g w hIdx hg1 ih =>
rcases ih (fun _ hg => hw _ (List.mem_cons_of_mem _ hg)) with
⟨w', hw'prod, hw'map⟩
refine ⟨cons g w' ?_ ?_, ?_⟩
· rwa [Word.fstIdx, ← List.head?_map, hw'map, List.head?_map]
· exact hw _ (List.mem_cons_self _ _)
· simp [hw'prod, hw'map]
|
import Mathlib.Algebra.Order.Floor
import Mathlib.Algebra.Order.Field.Power
import Mathlib.Data.Nat.Log
#align_import data.int.log from "leanprover-community/mathlib"@"1f0096e6caa61e9c849ec2adbd227e960e9dff58"
variable {R : Type*} [LinearOrderedSemifield R] [FloorSemiring R]
namespace Int
def log (b : ℕ) (r : R) : ℤ :=
if 1 ≤ r then Nat.log b ⌊r⌋₊ else -Nat.clog b ⌈r⁻¹⌉₊
#align int.log Int.log
theorem log_of_one_le_right (b : ℕ) {r : R} (hr : 1 ≤ r) : log b r = Nat.log b ⌊r⌋₊ :=
if_pos hr
#align int.log_of_one_le_right Int.log_of_one_le_right
| Mathlib/Data/Int/Log.lean | 66 | 70 | theorem log_of_right_le_one (b : ℕ) {r : R} (hr : r ≤ 1) : log b r = -Nat.clog b ⌈r⁻¹⌉₊ := by |
obtain rfl | hr := hr.eq_or_lt
· rw [log, if_pos hr, inv_one, Nat.ceil_one, Nat.floor_one, Nat.log_one_right, Nat.clog_one_right,
Int.ofNat_zero, neg_zero]
· exact if_neg hr.not_le
|
import Mathlib.CategoryTheory.Limits.Preserves.Shapes.Zero
#align_import category_theory.limits.shapes.kernels from "leanprover-community/mathlib"@"956af7c76589f444f2e1313911bad16366ea476d"
noncomputable section
universe v v₂ u u' u₂
open CategoryTheory
open CategoryTheory.Limits.WalkingParallelPair
namespace CategoryTheory.Limits
variable {C : Type u} [Category.{v} C]
variable [HasZeroMorphisms C]
abbrev HasKernel {X Y : C} (f : X ⟶ Y) : Prop :=
HasLimit (parallelPair f 0)
#align category_theory.limits.has_kernel CategoryTheory.Limits.HasKernel
abbrev HasCokernel {X Y : C} (f : X ⟶ Y) : Prop :=
HasColimit (parallelPair f 0)
#align category_theory.limits.has_cokernel CategoryTheory.Limits.HasCokernel
variable {X Y : C} (f : X ⟶ Y)
section
abbrev KernelFork :=
Fork f 0
#align category_theory.limits.kernel_fork CategoryTheory.Limits.KernelFork
variable {f}
@[reassoc (attr := simp)]
theorem KernelFork.condition (s : KernelFork f) : Fork.ι s ≫ f = 0 := by
erw [Fork.condition, HasZeroMorphisms.comp_zero]
#align category_theory.limits.kernel_fork.condition CategoryTheory.Limits.KernelFork.condition
-- Porting note (#10618): simp can prove this, removed simp tag
theorem KernelFork.app_one (s : KernelFork f) : s.π.app one = 0 := by
simp [Fork.app_one_eq_ι_comp_right]
#align category_theory.limits.kernel_fork.app_one CategoryTheory.Limits.KernelFork.app_one
abbrev KernelFork.ofι {Z : C} (ι : Z ⟶ X) (w : ι ≫ f = 0) : KernelFork f :=
Fork.ofι ι <| by rw [w, HasZeroMorphisms.comp_zero]
#align category_theory.limits.kernel_fork.of_ι CategoryTheory.Limits.KernelFork.ofι
@[simp]
theorem KernelFork.ι_ofι {X Y P : C} (f : X ⟶ Y) (ι : P ⟶ X) (w : ι ≫ f = 0) :
Fork.ι (KernelFork.ofι ι w) = ι := rfl
#align category_theory.limits.kernel_fork.ι_of_ι CategoryTheory.Limits.KernelFork.ι_ofι
section
-- attribute [local tidy] tactic.case_bash Porting note: no tidy nor case_bash
def isoOfι (s : Fork f 0) : s ≅ Fork.ofι (Fork.ι s) (Fork.condition s) :=
Cones.ext (Iso.refl _) <| by rintro ⟨j⟩ <;> simp
#align category_theory.limits.iso_of_ι CategoryTheory.Limits.isoOfι
def ofιCongr {P : C} {ι ι' : P ⟶ X} {w : ι ≫ f = 0} (h : ι = ι') :
KernelFork.ofι ι w ≅ KernelFork.ofι ι' (by rw [← h, w]) :=
Cones.ext (Iso.refl _)
#align category_theory.limits.of_ι_congr CategoryTheory.Limits.ofιCongr
def compNatIso {D : Type u'} [Category.{v} D] [HasZeroMorphisms D] (F : C ⥤ D) [F.IsEquivalence] :
parallelPair f 0 ⋙ F ≅ parallelPair (F.map f) 0 :=
let app (j :WalkingParallelPair) :
(parallelPair f 0 ⋙ F).obj j ≅ (parallelPair (F.map f) 0).obj j :=
match j with
| zero => Iso.refl _
| one => Iso.refl _
NatIso.ofComponents app <| by rintro ⟨i⟩ ⟨j⟩ <;> intro g <;> cases g <;> simp [app]
#align category_theory.limits.comp_nat_iso CategoryTheory.Limits.compNatIso
end
def KernelFork.IsLimit.lift' {s : KernelFork f} (hs : IsLimit s) {W : C} (k : W ⟶ X)
(h : k ≫ f = 0) : { l : W ⟶ s.pt // l ≫ Fork.ι s = k } :=
⟨hs.lift <| KernelFork.ofι _ h, hs.fac _ _⟩
#align category_theory.limits.kernel_fork.is_limit.lift' CategoryTheory.Limits.KernelFork.IsLimit.lift'
def isLimitAux (t : KernelFork f) (lift : ∀ s : KernelFork f, s.pt ⟶ t.pt)
(fac : ∀ s : KernelFork f, lift s ≫ t.ι = s.ι)
(uniq : ∀ (s : KernelFork f) (m : s.pt ⟶ t.pt) (_ : m ≫ t.ι = s.ι), m = lift s) : IsLimit t :=
{ lift
fac := fun s j => by
cases j
· exact fac s
· simp
uniq := fun s m w => uniq s m (w Limits.WalkingParallelPair.zero) }
#align category_theory.limits.is_limit_aux CategoryTheory.Limits.isLimitAux
def KernelFork.IsLimit.ofι {W : C} (g : W ⟶ X) (eq : g ≫ f = 0)
(lift : ∀ {W' : C} (g' : W' ⟶ X) (_ : g' ≫ f = 0), W' ⟶ W)
(fac : ∀ {W' : C} (g' : W' ⟶ X) (eq' : g' ≫ f = 0), lift g' eq' ≫ g = g')
(uniq :
∀ {W' : C} (g' : W' ⟶ X) (eq' : g' ≫ f = 0) (m : W' ⟶ W) (_ : m ≫ g = g'), m = lift g' eq') :
IsLimit (KernelFork.ofι g eq) :=
isLimitAux _ (fun s => lift s.ι s.condition) (fun s => fac s.ι s.condition) fun s =>
uniq s.ι s.condition
#align category_theory.limits.kernel_fork.is_limit.of_ι CategoryTheory.Limits.KernelFork.IsLimit.ofι
def KernelFork.IsLimit.ofι' {X Y K : C} {f : X ⟶ Y} (i : K ⟶ X) (w : i ≫ f = 0)
(h : ∀ {A : C} (k : A ⟶ X) (_ : k ≫ f = 0), { l : A ⟶ K // l ≫ i = k}) [hi : Mono i] :
IsLimit (KernelFork.ofι i w) :=
ofι _ _ (fun {A} k hk => (h k hk).1) (fun {A} k hk => (h k hk).2) (fun {A} k hk m hm => by
rw [← cancel_mono i, (h k hk).2, hm])
def isKernelCompMono {c : KernelFork f} (i : IsLimit c) {Z} (g : Y ⟶ Z) [hg : Mono g] {h : X ⟶ Z}
(hh : h = f ≫ g) : IsLimit (KernelFork.ofι c.ι (by simp [hh]) : KernelFork h) :=
Fork.IsLimit.mk' _ fun s =>
let s' : KernelFork f := Fork.ofι s.ι (by rw [← cancel_mono g]; simp [← hh, s.condition])
let l := KernelFork.IsLimit.lift' i s'.ι s'.condition
⟨l.1, l.2, fun hm => by
apply Fork.IsLimit.hom_ext i; rw [Fork.ι_ofι] at hm; rw [hm]; exact l.2.symm⟩
#align category_theory.limits.is_kernel_comp_mono CategoryTheory.Limits.isKernelCompMono
theorem isKernelCompMono_lift {c : KernelFork f} (i : IsLimit c) {Z} (g : Y ⟶ Z) [hg : Mono g]
{h : X ⟶ Z} (hh : h = f ≫ g) (s : KernelFork h) :
(isKernelCompMono i g hh).lift s = i.lift (Fork.ofι s.ι (by
rw [← cancel_mono g, Category.assoc, ← hh]
simp)) := rfl
#align category_theory.limits.is_kernel_comp_mono_lift CategoryTheory.Limits.isKernelCompMono_lift
def isKernelOfComp {W : C} (g : Y ⟶ W) (h : X ⟶ W) {c : KernelFork h} (i : IsLimit c)
(hf : c.ι ≫ f = 0) (hfg : f ≫ g = h) : IsLimit (KernelFork.ofι c.ι hf) :=
Fork.IsLimit.mk _ (fun s => i.lift (KernelFork.ofι s.ι (by simp [← hfg])))
(fun s => by simp only [KernelFork.ι_ofι, Fork.IsLimit.lift_ι]) fun s m h => by
apply Fork.IsLimit.hom_ext i; simpa using h
#align category_theory.limits.is_kernel_of_comp CategoryTheory.Limits.isKernelOfComp
def KernelFork.IsLimit.ofId {X Y : C} (f : X ⟶ Y) (hf : f = 0) :
IsLimit (KernelFork.ofι (𝟙 X) (show 𝟙 X ≫ f = 0 by rw [hf, comp_zero])) :=
KernelFork.IsLimit.ofι _ _ (fun x _ => x) (fun _ _ => Category.comp_id _)
(fun _ _ _ hb => by simp only [← hb, Category.comp_id])
def KernelFork.IsLimit.ofMonoOfIsZero {X Y : C} {f : X ⟶ Y} (c : KernelFork f)
(hf : Mono f) (h : IsZero c.pt) : IsLimit c :=
isLimitAux _ (fun s => 0) (fun s => by rw [zero_comp, ← cancel_mono f, zero_comp, s.condition])
(fun _ _ _ => h.eq_of_tgt _ _)
lemma KernelFork.IsLimit.isIso_ι {X Y : C} {f : X ⟶ Y} (c : KernelFork f)
(hc : IsLimit c) (hf : f = 0) : IsIso c.ι := by
let e : c.pt ≅ X := IsLimit.conePointUniqueUpToIso hc
(KernelFork.IsLimit.ofId (f : X ⟶ Y) hf)
have eq : e.inv ≫ c.ι = 𝟙 X := Fork.IsLimit.lift_ι hc
haveI : IsIso (e.inv ≫ c.ι) := by
rw [eq]
infer_instance
exact IsIso.of_isIso_comp_left e.inv c.ι
end
section
variable [HasKernel f]
abbrev kernel (f : X ⟶ Y) [HasKernel f] : C :=
equalizer f 0
#align category_theory.limits.kernel CategoryTheory.Limits.kernel
abbrev kernel.ι : kernel f ⟶ X :=
equalizer.ι f 0
#align category_theory.limits.kernel.ι CategoryTheory.Limits.kernel.ι
@[simp]
theorem equalizer_as_kernel : equalizer.ι f 0 = kernel.ι f := rfl
#align category_theory.limits.equalizer_as_kernel CategoryTheory.Limits.equalizer_as_kernel
@[reassoc (attr := simp)]
theorem kernel.condition : kernel.ι f ≫ f = 0 :=
KernelFork.condition _
#align category_theory.limits.kernel.condition CategoryTheory.Limits.kernel.condition
def kernelIsKernel : IsLimit (Fork.ofι (kernel.ι f) ((kernel.condition f).trans comp_zero.symm)) :=
IsLimit.ofIsoLimit (limit.isLimit _) (Fork.ext (Iso.refl _) (by aesop_cat))
#align category_theory.limits.kernel_is_kernel CategoryTheory.Limits.kernelIsKernel
abbrev kernel.lift {W : C} (k : W ⟶ X) (h : k ≫ f = 0) : W ⟶ kernel f :=
(kernelIsKernel f).lift (KernelFork.ofι k h)
#align category_theory.limits.kernel.lift CategoryTheory.Limits.kernel.lift
@[reassoc (attr := simp)]
theorem kernel.lift_ι {W : C} (k : W ⟶ X) (h : k ≫ f = 0) : kernel.lift f k h ≫ kernel.ι f = k :=
(kernelIsKernel f).fac (KernelFork.ofι k h) WalkingParallelPair.zero
#align category_theory.limits.kernel.lift_ι CategoryTheory.Limits.kernel.lift_ι
@[simp]
theorem kernel.lift_zero {W : C} {h} : kernel.lift f (0 : W ⟶ X) h = 0 := by
ext; simp
#align category_theory.limits.kernel.lift_zero CategoryTheory.Limits.kernel.lift_zero
instance kernel.lift_mono {W : C} (k : W ⟶ X) (h : k ≫ f = 0) [Mono k] : Mono (kernel.lift f k h) :=
⟨fun {Z} g g' w => by
replace w := w =≫ kernel.ι f
simp only [Category.assoc, kernel.lift_ι] at w
exact (cancel_mono k).1 w⟩
#align category_theory.limits.kernel.lift_mono CategoryTheory.Limits.kernel.lift_mono
def kernel.lift' {W : C} (k : W ⟶ X) (h : k ≫ f = 0) : { l : W ⟶ kernel f // l ≫ kernel.ι f = k } :=
⟨kernel.lift f k h, kernel.lift_ι _ _ _⟩
#align category_theory.limits.kernel.lift' CategoryTheory.Limits.kernel.lift'
abbrev kernel.map {X' Y' : C} (f' : X' ⟶ Y') [HasKernel f'] (p : X ⟶ X') (q : Y ⟶ Y')
(w : f ≫ q = p ≫ f') : kernel f ⟶ kernel f' :=
kernel.lift f' (kernel.ι f ≫ p) (by simp [← w])
#align category_theory.limits.kernel.map CategoryTheory.Limits.kernel.map
theorem kernel.lift_map {X Y Z X' Y' Z' : C} (f : X ⟶ Y) (g : Y ⟶ Z) [HasKernel g] (w : f ≫ g = 0)
(f' : X' ⟶ Y') (g' : Y' ⟶ Z') [HasKernel g'] (w' : f' ≫ g' = 0) (p : X ⟶ X') (q : Y ⟶ Y')
(r : Z ⟶ Z') (h₁ : f ≫ q = p ≫ f') (h₂ : g ≫ r = q ≫ g') :
kernel.lift g f w ≫ kernel.map g g' q r h₂ = p ≫ kernel.lift g' f' w' := by
ext; simp [h₁]
#align category_theory.limits.kernel.lift_map CategoryTheory.Limits.kernel.lift_map
@[simps]
def kernel.mapIso {X' Y' : C} (f' : X' ⟶ Y') [HasKernel f'] (p : X ≅ X') (q : Y ≅ Y')
(w : f ≫ q.hom = p.hom ≫ f') : kernel f ≅ kernel f' where
hom := kernel.map f f' p.hom q.hom w
inv :=
kernel.map f' f p.inv q.inv
(by
refine (cancel_mono q.hom).1 ?_
simp [w])
#align category_theory.limits.kernel.map_iso CategoryTheory.Limits.kernel.mapIso
instance kernel.ι_zero_isIso : IsIso (kernel.ι (0 : X ⟶ Y)) :=
equalizer.ι_of_self _
#align category_theory.limits.kernel.ι_zero_is_iso CategoryTheory.Limits.kernel.ι_zero_isIso
theorem eq_zero_of_epi_kernel [Epi (kernel.ι f)] : f = 0 :=
(cancel_epi (kernel.ι f)).1 (by simp)
#align category_theory.limits.eq_zero_of_epi_kernel CategoryTheory.Limits.eq_zero_of_epi_kernel
def kernelZeroIsoSource : kernel (0 : X ⟶ Y) ≅ X :=
equalizer.isoSourceOfSelf 0
#align category_theory.limits.kernel_zero_iso_source CategoryTheory.Limits.kernelZeroIsoSource
@[simp]
theorem kernelZeroIsoSource_hom : kernelZeroIsoSource.hom = kernel.ι (0 : X ⟶ Y) := rfl
#align category_theory.limits.kernel_zero_iso_source_hom CategoryTheory.Limits.kernelZeroIsoSource_hom
@[simp]
theorem kernelZeroIsoSource_inv :
kernelZeroIsoSource.inv = kernel.lift (0 : X ⟶ Y) (𝟙 X) (by simp) := by
ext
simp [kernelZeroIsoSource]
#align category_theory.limits.kernel_zero_iso_source_inv CategoryTheory.Limits.kernelZeroIsoSource_inv
def kernelIsoOfEq {f g : X ⟶ Y} [HasKernel f] [HasKernel g] (h : f = g) : kernel f ≅ kernel g :=
HasLimit.isoOfNatIso (by rw [h])
#align category_theory.limits.kernel_iso_of_eq CategoryTheory.Limits.kernelIsoOfEq
@[simp]
theorem kernelIsoOfEq_refl {h : f = f} : kernelIsoOfEq h = Iso.refl (kernel f) := by
ext
simp [kernelIsoOfEq]
#align category_theory.limits.kernel_iso_of_eq_refl CategoryTheory.Limits.kernelIsoOfEq_refl
@[reassoc (attr := simp)]
theorem kernelIsoOfEq_hom_comp_ι {f g : X ⟶ Y} [HasKernel f] [HasKernel g] (h : f = g) :
(kernelIsoOfEq h).hom ≫ kernel.ι g = kernel.ι f := by
cases h; simp
#align category_theory.limits.kernel_iso_of_eq_hom_comp_ι CategoryTheory.Limits.kernelIsoOfEq_hom_comp_ι
@[reassoc (attr := simp)]
theorem kernelIsoOfEq_inv_comp_ι {f g : X ⟶ Y} [HasKernel f] [HasKernel g] (h : f = g) :
(kernelIsoOfEq h).inv ≫ kernel.ι _ = kernel.ι _ := by
cases h; simp
#align category_theory.limits.kernel_iso_of_eq_inv_comp_ι CategoryTheory.Limits.kernelIsoOfEq_inv_comp_ι
@[reassoc (attr := simp)]
theorem lift_comp_kernelIsoOfEq_hom {Z} {f g : X ⟶ Y} [HasKernel f] [HasKernel g] (h : f = g)
(e : Z ⟶ X) (he) :
kernel.lift _ e he ≫ (kernelIsoOfEq h).hom = kernel.lift _ e (by simp [← h, he]) := by
cases h; simp
#align category_theory.limits.lift_comp_kernel_iso_of_eq_hom CategoryTheory.Limits.lift_comp_kernelIsoOfEq_hom
@[reassoc (attr := simp)]
theorem lift_comp_kernelIsoOfEq_inv {Z} {f g : X ⟶ Y} [HasKernel f] [HasKernel g] (h : f = g)
(e : Z ⟶ X) (he) :
kernel.lift _ e he ≫ (kernelIsoOfEq h).inv = kernel.lift _ e (by simp [h, he]) := by
cases h; simp
#align category_theory.limits.lift_comp_kernel_iso_of_eq_inv CategoryTheory.Limits.lift_comp_kernelIsoOfEq_inv
@[simp]
theorem kernelIsoOfEq_trans {f g h : X ⟶ Y} [HasKernel f] [HasKernel g] [HasKernel h] (w₁ : f = g)
(w₂ : g = h) : kernelIsoOfEq w₁ ≪≫ kernelIsoOfEq w₂ = kernelIsoOfEq (w₁.trans w₂) := by
cases w₁; cases w₂; ext; simp [kernelIsoOfEq]
#align category_theory.limits.kernel_iso_of_eq_trans CategoryTheory.Limits.kernelIsoOfEq_trans
variable {f}
theorem kernel_not_epi_of_nonzero (w : f ≠ 0) : ¬Epi (kernel.ι f) := fun _ =>
w (eq_zero_of_epi_kernel f)
#align category_theory.limits.kernel_not_epi_of_nonzero CategoryTheory.Limits.kernel_not_epi_of_nonzero
theorem kernel_not_iso_of_nonzero (w : f ≠ 0) : IsIso (kernel.ι f) → False := fun _ =>
kernel_not_epi_of_nonzero w inferInstance
#align category_theory.limits.kernel_not_iso_of_nonzero CategoryTheory.Limits.kernel_not_iso_of_nonzero
instance hasKernel_comp_mono {X Y Z : C} (f : X ⟶ Y) [HasKernel f] (g : Y ⟶ Z) [Mono g] :
HasKernel (f ≫ g) :=
⟨⟨{ cone := _
isLimit := isKernelCompMono (limit.isLimit _) g rfl }⟩⟩
#align category_theory.limits.has_kernel_comp_mono CategoryTheory.Limits.hasKernel_comp_mono
@[simps]
def kernelCompMono {X Y Z : C} (f : X ⟶ Y) (g : Y ⟶ Z) [HasKernel f] [Mono g] :
kernel (f ≫ g) ≅ kernel f where
hom :=
kernel.lift _ (kernel.ι _)
(by
rw [← cancel_mono g]
simp)
inv := kernel.lift _ (kernel.ι _) (by simp)
#align category_theory.limits.kernel_comp_mono CategoryTheory.Limits.kernelCompMono
#adaptation_note
instance hasKernel_iso_comp {X Y Z : C} (f : X ⟶ Y) (g : Y ⟶ Z) [IsIso f] [HasKernel g] :
HasKernel (f ≫ g) where
exists_limit :=
⟨{ cone := KernelFork.ofι (kernel.ι g ≫ inv f) (by simp)
isLimit := isLimitAux _ (fun s => kernel.lift _ (s.ι ≫ f) (by aesop_cat))
(by aesop_cat) fun s m w => by
simp_rw [← w]
symm
apply equalizer.hom_ext
simp }⟩
#align category_theory.limits.has_kernel_iso_comp CategoryTheory.Limits.hasKernel_iso_comp
@[simps]
def kernelIsIsoComp {X Y Z : C} (f : X ⟶ Y) (g : Y ⟶ Z) [IsIso f] [HasKernel g] :
kernel (f ≫ g) ≅ kernel g where
hom := kernel.lift _ (kernel.ι _ ≫ f) (by simp)
inv := kernel.lift _ (kernel.ι _ ≫ inv f) (by simp)
#align category_theory.limits.kernel_is_iso_comp CategoryTheory.Limits.kernelIsIsoComp
end
section
variable (X Y)
theorem kernel.ι_of_zero : IsIso (kernel.ι (0 : X ⟶ Y)) :=
equalizer.ι_of_self _
#align category_theory.limits.kernel.ι_of_zero CategoryTheory.Limits.kernel.ι_of_zero
end
section
abbrev CokernelCofork :=
Cofork f 0
#align category_theory.limits.cokernel_cofork CategoryTheory.Limits.CokernelCofork
variable {f}
@[reassoc (attr := simp)]
theorem CokernelCofork.condition (s : CokernelCofork f) : f ≫ s.π = 0 := by
rw [Cofork.condition, zero_comp]
#align category_theory.limits.cokernel_cofork.condition CategoryTheory.Limits.CokernelCofork.condition
-- Porting note (#10618): simp can prove this, removed simp tag
theorem CokernelCofork.π_eq_zero (s : CokernelCofork f) : s.ι.app zero = 0 := by
simp [Cofork.app_zero_eq_comp_π_right]
#align category_theory.limits.cokernel_cofork.π_eq_zero CategoryTheory.Limits.CokernelCofork.π_eq_zero
abbrev CokernelCofork.ofπ {Z : C} (π : Y ⟶ Z) (w : f ≫ π = 0) : CokernelCofork f :=
Cofork.ofπ π <| by rw [w, zero_comp]
#align category_theory.limits.cokernel_cofork.of_π CategoryTheory.Limits.CokernelCofork.ofπ
@[simp]
theorem CokernelCofork.π_ofπ {X Y P : C} (f : X ⟶ Y) (π : Y ⟶ P) (w : f ≫ π = 0) :
Cofork.π (CokernelCofork.ofπ π w) = π :=
rfl
#align category_theory.limits.cokernel_cofork.π_of_π CategoryTheory.Limits.CokernelCofork.π_ofπ
def isoOfπ (s : Cofork f 0) : s ≅ Cofork.ofπ (Cofork.π s) (Cofork.condition s) :=
Cocones.ext (Iso.refl _) fun j => by cases j <;> aesop_cat
#align category_theory.limits.iso_of_π CategoryTheory.Limits.isoOfπ
def ofπCongr {P : C} {π π' : Y ⟶ P} {w : f ≫ π = 0} (h : π = π') :
CokernelCofork.ofπ π w ≅ CokernelCofork.ofπ π' (by rw [← h, w]) :=
Cocones.ext (Iso.refl _) fun j => by cases j <;> aesop_cat
#align category_theory.limits.of_π_congr CategoryTheory.Limits.ofπCongr
def CokernelCofork.IsColimit.desc' {s : CokernelCofork f} (hs : IsColimit s) {W : C} (k : Y ⟶ W)
(h : f ≫ k = 0) : { l : s.pt ⟶ W // Cofork.π s ≫ l = k } :=
⟨hs.desc <| CokernelCofork.ofπ _ h, hs.fac _ _⟩
#align category_theory.limits.cokernel_cofork.is_colimit.desc' CategoryTheory.Limits.CokernelCofork.IsColimit.desc'
def isColimitAux (t : CokernelCofork f) (desc : ∀ s : CokernelCofork f, t.pt ⟶ s.pt)
(fac : ∀ s : CokernelCofork f, t.π ≫ desc s = s.π)
(uniq : ∀ (s : CokernelCofork f) (m : t.pt ⟶ s.pt) (_ : t.π ≫ m = s.π), m = desc s) :
IsColimit t :=
{ desc
fac := fun s j => by
cases j
· simp
· exact fac s
uniq := fun s m w => uniq s m (w Limits.WalkingParallelPair.one) }
#align category_theory.limits.is_colimit_aux CategoryTheory.Limits.isColimitAux
def CokernelCofork.IsColimit.ofπ {Z : C} (g : Y ⟶ Z) (eq : f ≫ g = 0)
(desc : ∀ {Z' : C} (g' : Y ⟶ Z') (_ : f ≫ g' = 0), Z ⟶ Z')
(fac : ∀ {Z' : C} (g' : Y ⟶ Z') (eq' : f ≫ g' = 0), g ≫ desc g' eq' = g')
(uniq :
∀ {Z' : C} (g' : Y ⟶ Z') (eq' : f ≫ g' = 0) (m : Z ⟶ Z') (_ : g ≫ m = g'), m = desc g' eq') :
IsColimit (CokernelCofork.ofπ g eq) :=
isColimitAux _ (fun s => desc s.π s.condition) (fun s => fac s.π s.condition) fun s =>
uniq s.π s.condition
#align category_theory.limits.cokernel_cofork.is_colimit.of_π CategoryTheory.Limits.CokernelCofork.IsColimit.ofπ
def CokernelCofork.IsColimit.ofπ' {X Y Q : C} {f : X ⟶ Y} (p : Y ⟶ Q) (w : f ≫ p = 0)
(h : ∀ {A : C} (k : Y ⟶ A) (_ : f ≫ k = 0), { l : Q ⟶ A // p ≫ l = k}) [hp : Epi p] :
IsColimit (CokernelCofork.ofπ p w) :=
ofπ _ _ (fun {A} k hk => (h k hk).1) (fun {A} k hk => (h k hk).2) (fun {A} k hk m hm => by
rw [← cancel_epi p, (h k hk).2, hm])
def isCokernelEpiComp {c : CokernelCofork f} (i : IsColimit c) {W} (g : W ⟶ X) [hg : Epi g]
{h : W ⟶ Y} (hh : h = g ≫ f) :
IsColimit (CokernelCofork.ofπ c.π (by rw [hh]; simp) : CokernelCofork h) :=
Cofork.IsColimit.mk' _ fun s =>
let s' : CokernelCofork f :=
Cofork.ofπ s.π
(by
apply hg.left_cancellation
rw [← Category.assoc, ← hh, s.condition]
simp)
let l := CokernelCofork.IsColimit.desc' i s'.π s'.condition
⟨l.1, l.2, fun hm => by
apply Cofork.IsColimit.hom_ext i; rw [Cofork.π_ofπ] at hm; rw [hm]; exact l.2.symm⟩
#align category_theory.limits.is_cokernel_epi_comp CategoryTheory.Limits.isCokernelEpiComp
@[simp]
theorem isCokernelEpiComp_desc {c : CokernelCofork f} (i : IsColimit c) {W} (g : W ⟶ X) [hg : Epi g]
{h : W ⟶ Y} (hh : h = g ≫ f) (s : CokernelCofork h) :
(isCokernelEpiComp i g hh).desc s =
i.desc
(Cofork.ofπ s.π
(by
rw [← cancel_epi g, ← Category.assoc, ← hh]
simp)) :=
rfl
#align category_theory.limits.is_cokernel_epi_comp_desc CategoryTheory.Limits.isCokernelEpiComp_desc
def isCokernelOfComp {W : C} (g : W ⟶ X) (h : W ⟶ Y) {c : CokernelCofork h} (i : IsColimit c)
(hf : f ≫ c.π = 0) (hfg : g ≫ f = h) : IsColimit (CokernelCofork.ofπ c.π hf) :=
Cofork.IsColimit.mk _ (fun s => i.desc (CokernelCofork.ofπ s.π (by simp [← hfg])))
(fun s => by simp only [CokernelCofork.π_ofπ, Cofork.IsColimit.π_desc]) fun s m h => by
apply Cofork.IsColimit.hom_ext i
simpa using h
#align category_theory.limits.is_cokernel_of_comp CategoryTheory.Limits.isCokernelOfComp
def CokernelCofork.IsColimit.ofId {X Y : C} (f : X ⟶ Y) (hf : f = 0) :
IsColimit (CokernelCofork.ofπ (𝟙 Y) (show f ≫ 𝟙 Y = 0 by rw [hf, zero_comp])) :=
CokernelCofork.IsColimit.ofπ _ _ (fun x _ => x) (fun _ _ => Category.id_comp _)
(fun _ _ _ hb => by simp only [← hb, Category.id_comp])
def CokernelCofork.IsColimit.ofEpiOfIsZero {X Y : C} {f : X ⟶ Y} (c : CokernelCofork f)
(hf : Epi f) (h : IsZero c.pt) : IsColimit c :=
isColimitAux _ (fun s => 0) (fun s => by rw [comp_zero, ← cancel_epi f, comp_zero, s.condition])
(fun _ _ _ => h.eq_of_src _ _)
lemma CokernelCofork.IsColimit.isIso_π {X Y : C} {f : X ⟶ Y} (c : CokernelCofork f)
(hc : IsColimit c) (hf : f = 0) : IsIso c.π := by
let e : c.pt ≅ Y := IsColimit.coconePointUniqueUpToIso hc
(CokernelCofork.IsColimit.ofId (f : X ⟶ Y) hf)
have eq : c.π ≫ e.hom = 𝟙 Y := Cofork.IsColimit.π_desc hc
haveI : IsIso (c.π ≫ e.hom) := by
rw [eq]
dsimp
infer_instance
exact IsIso.of_isIso_comp_right c.π e.hom
end
section
variable [HasCokernel f]
abbrev cokernel : C :=
coequalizer f 0
#align category_theory.limits.cokernel CategoryTheory.Limits.cokernel
abbrev cokernel.π : Y ⟶ cokernel f :=
coequalizer.π f 0
#align category_theory.limits.cokernel.π CategoryTheory.Limits.cokernel.π
@[simp]
theorem coequalizer_as_cokernel : coequalizer.π f 0 = cokernel.π f :=
rfl
#align category_theory.limits.coequalizer_as_cokernel CategoryTheory.Limits.coequalizer_as_cokernel
@[reassoc (attr := simp)]
theorem cokernel.condition : f ≫ cokernel.π f = 0 :=
CokernelCofork.condition _
#align category_theory.limits.cokernel.condition CategoryTheory.Limits.cokernel.condition
def cokernelIsCokernel :
IsColimit (Cofork.ofπ (cokernel.π f) ((cokernel.condition f).trans zero_comp.symm)) :=
IsColimit.ofIsoColimit (colimit.isColimit _) (Cofork.ext (Iso.refl _))
#align category_theory.limits.cokernel_is_cokernel CategoryTheory.Limits.cokernelIsCokernel
abbrev cokernel.desc {W : C} (k : Y ⟶ W) (h : f ≫ k = 0) : cokernel f ⟶ W :=
(cokernelIsCokernel f).desc (CokernelCofork.ofπ k h)
#align category_theory.limits.cokernel.desc CategoryTheory.Limits.cokernel.desc
@[reassoc (attr := simp)]
theorem cokernel.π_desc {W : C} (k : Y ⟶ W) (h : f ≫ k = 0) :
cokernel.π f ≫ cokernel.desc f k h = k :=
(cokernelIsCokernel f).fac (CokernelCofork.ofπ k h) WalkingParallelPair.one
#align category_theory.limits.cokernel.π_desc CategoryTheory.Limits.cokernel.π_desc
-- Porting note: added to ease the port of `Abelian.Exact`
@[reassoc (attr := simp)]
lemma colimit_ι_zero_cokernel_desc {C : Type*} [Category C]
[HasZeroMorphisms C] {X Y Z : C} (f : X ⟶ Y) (g : Y ⟶ Z) (h : f ≫ g = 0) [HasCokernel f] :
colimit.ι (parallelPair f 0) WalkingParallelPair.zero ≫ cokernel.desc f g h = 0 := by
rw [(colimit.w (parallelPair f 0) WalkingParallelPairHom.left).symm]
aesop_cat
@[simp]
theorem cokernel.desc_zero {W : C} {h} : cokernel.desc f (0 : Y ⟶ W) h = 0 := by
ext; simp
#align category_theory.limits.cokernel.desc_zero CategoryTheory.Limits.cokernel.desc_zero
instance cokernel.desc_epi {W : C} (k : Y ⟶ W) (h : f ≫ k = 0) [Epi k] :
Epi (cokernel.desc f k h) :=
⟨fun {Z} g g' w => by
replace w := cokernel.π f ≫= w
simp only [cokernel.π_desc_assoc] at w
exact (cancel_epi k).1 w⟩
#align category_theory.limits.cokernel.desc_epi CategoryTheory.Limits.cokernel.desc_epi
def cokernel.desc' {W : C} (k : Y ⟶ W) (h : f ≫ k = 0) :
{ l : cokernel f ⟶ W // cokernel.π f ≫ l = k } :=
⟨cokernel.desc f k h, cokernel.π_desc _ _ _⟩
#align category_theory.limits.cokernel.desc' CategoryTheory.Limits.cokernel.desc'
abbrev cokernel.map {X' Y' : C} (f' : X' ⟶ Y') [HasCokernel f'] (p : X ⟶ X') (q : Y ⟶ Y')
(w : f ≫ q = p ≫ f') : cokernel f ⟶ cokernel f' :=
cokernel.desc f (q ≫ cokernel.π f') (by
have : f ≫ q ≫ π f' = p ≫ f' ≫ π f' := by
simp only [← Category.assoc]
apply congrArg (· ≫ π f') w
simp [this])
#align category_theory.limits.cokernel.map CategoryTheory.Limits.cokernel.map
theorem cokernel.map_desc {X Y Z X' Y' Z' : C} (f : X ⟶ Y) [HasCokernel f] (g : Y ⟶ Z)
(w : f ≫ g = 0) (f' : X' ⟶ Y') [HasCokernel f'] (g' : Y' ⟶ Z') (w' : f' ≫ g' = 0) (p : X ⟶ X')
(q : Y ⟶ Y') (r : Z ⟶ Z') (h₁ : f ≫ q = p ≫ f') (h₂ : g ≫ r = q ≫ g') :
cokernel.map f f' p q h₁ ≫ cokernel.desc f' g' w' = cokernel.desc f g w ≫ r := by
ext; simp [h₂]
#align category_theory.limits.cokernel.map_desc CategoryTheory.Limits.cokernel.map_desc
@[simps]
def cokernel.mapIso {X' Y' : C} (f' : X' ⟶ Y') [HasCokernel f'] (p : X ≅ X') (q : Y ≅ Y')
(w : f ≫ q.hom = p.hom ≫ f') : cokernel f ≅ cokernel f' where
hom := cokernel.map f f' p.hom q.hom w
inv := cokernel.map f' f p.inv q.inv (by
refine (cancel_mono q.hom).1 ?_
simp [w])
#align category_theory.limits.cokernel.map_iso CategoryTheory.Limits.cokernel.mapIso
instance cokernel.π_zero_isIso : IsIso (cokernel.π (0 : X ⟶ Y)) :=
coequalizer.π_of_self _
#align category_theory.limits.cokernel.π_zero_is_iso CategoryTheory.Limits.cokernel.π_zero_isIso
theorem eq_zero_of_mono_cokernel [Mono (cokernel.π f)] : f = 0 :=
(cancel_mono (cokernel.π f)).1 (by simp)
#align category_theory.limits.eq_zero_of_mono_cokernel CategoryTheory.Limits.eq_zero_of_mono_cokernel
def cokernelZeroIsoTarget : cokernel (0 : X ⟶ Y) ≅ Y :=
coequalizer.isoTargetOfSelf 0
#align category_theory.limits.cokernel_zero_iso_target CategoryTheory.Limits.cokernelZeroIsoTarget
@[simp]
theorem cokernelZeroIsoTarget_hom :
cokernelZeroIsoTarget.hom = cokernel.desc (0 : X ⟶ Y) (𝟙 Y) (by simp) := by
ext; simp [cokernelZeroIsoTarget]
#align category_theory.limits.cokernel_zero_iso_target_hom CategoryTheory.Limits.cokernelZeroIsoTarget_hom
@[simp]
theorem cokernelZeroIsoTarget_inv : cokernelZeroIsoTarget.inv = cokernel.π (0 : X ⟶ Y) :=
rfl
#align category_theory.limits.cokernel_zero_iso_target_inv CategoryTheory.Limits.cokernelZeroIsoTarget_inv
def cokernelIsoOfEq {f g : X ⟶ Y} [HasCokernel f] [HasCokernel g] (h : f = g) :
cokernel f ≅ cokernel g :=
HasColimit.isoOfNatIso (by simp [h]; rfl)
#align category_theory.limits.cokernel_iso_of_eq CategoryTheory.Limits.cokernelIsoOfEq
@[simp]
theorem cokernelIsoOfEq_refl {h : f = f} : cokernelIsoOfEq h = Iso.refl (cokernel f) := by
ext; simp [cokernelIsoOfEq]
#align category_theory.limits.cokernel_iso_of_eq_refl CategoryTheory.Limits.cokernelIsoOfEq_refl
@[reassoc (attr := simp)]
theorem π_comp_cokernelIsoOfEq_hom {f g : X ⟶ Y} [HasCokernel f] [HasCokernel g] (h : f = g) :
cokernel.π f ≫ (cokernelIsoOfEq h).hom = cokernel.π g := by
cases h; simp
#align category_theory.limits.π_comp_cokernel_iso_of_eq_hom CategoryTheory.Limits.π_comp_cokernelIsoOfEq_hom
@[reassoc (attr := simp)]
theorem π_comp_cokernelIsoOfEq_inv {f g : X ⟶ Y} [HasCokernel f] [HasCokernel g] (h : f = g) :
cokernel.π _ ≫ (cokernelIsoOfEq h).inv = cokernel.π _ := by
cases h; simp
#align category_theory.limits.π_comp_cokernel_iso_of_eq_inv CategoryTheory.Limits.π_comp_cokernelIsoOfEq_inv
@[reassoc (attr := simp)]
| Mathlib/CategoryTheory/Limits/Shapes/Kernels.lean | 902 | 905 | theorem cokernelIsoOfEq_hom_comp_desc {Z} {f g : X ⟶ Y} [HasCokernel f] [HasCokernel g] (h : f = g)
(e : Y ⟶ Z) (he) :
(cokernelIsoOfEq h).hom ≫ cokernel.desc _ e he = cokernel.desc _ e (by simp [h, he]) := by |
cases h; simp
|
import Mathlib.Data.Fintype.List
#align_import data.list.cycle from "leanprover-community/mathlib"@"7413128c3bcb3b0818e3e18720abc9ea3100fb49"
assert_not_exists MonoidWithZero
namespace List
variable {α : Type*} [DecidableEq α]
def nextOr : ∀ (_ : List α) (_ _ : α), α
| [], _, default => default
| [_], _, default => default
-- Handles the not-found and the wraparound case
| y :: z :: xs, x, default => if x = y then z else nextOr (z :: xs) x default
#align list.next_or List.nextOr
@[simp]
theorem nextOr_nil (x d : α) : nextOr [] x d = d :=
rfl
#align list.next_or_nil List.nextOr_nil
@[simp]
theorem nextOr_singleton (x y d : α) : nextOr [y] x d = d :=
rfl
#align list.next_or_singleton List.nextOr_singleton
@[simp]
theorem nextOr_self_cons_cons (xs : List α) (x y d : α) : nextOr (x :: y :: xs) x d = y :=
if_pos rfl
#align list.next_or_self_cons_cons List.nextOr_self_cons_cons
theorem nextOr_cons_of_ne (xs : List α) (y x d : α) (h : x ≠ y) :
nextOr (y :: xs) x d = nextOr xs x d := by
cases' xs with z zs
· rfl
· exact if_neg h
#align list.next_or_cons_of_ne List.nextOr_cons_of_ne
theorem nextOr_eq_nextOr_of_mem_of_ne (xs : List α) (x d d' : α) (x_mem : x ∈ xs)
(x_ne : x ≠ xs.getLast (ne_nil_of_mem x_mem)) : nextOr xs x d = nextOr xs x d' := by
induction' xs with y ys IH
· cases x_mem
cases' ys with z zs
· simp at x_mem x_ne
contradiction
by_cases h : x = y
· rw [h, nextOr_self_cons_cons, nextOr_self_cons_cons]
· rw [nextOr, nextOr, IH]
· simpa [h] using x_mem
· simpa using x_ne
#align list.next_or_eq_next_or_of_mem_of_ne List.nextOr_eq_nextOr_of_mem_of_ne
theorem mem_of_nextOr_ne {xs : List α} {x d : α} (h : nextOr xs x d ≠ d) : x ∈ xs := by
induction' xs with y ys IH
· simp at h
cases' ys with z zs
· simp at h
· by_cases hx : x = y
· simp [hx]
· rw [nextOr_cons_of_ne _ _ _ _ hx] at h
simpa [hx] using IH h
#align list.mem_of_next_or_ne List.mem_of_nextOr_ne
theorem nextOr_concat {xs : List α} {x : α} (d : α) (h : x ∉ xs) : nextOr (xs ++ [x]) x d = d := by
induction' xs with z zs IH
· simp
· obtain ⟨hz, hzs⟩ := not_or.mp (mt mem_cons.2 h)
rw [cons_append, nextOr_cons_of_ne _ _ _ _ hz, IH hzs]
#align list.next_or_concat List.nextOr_concat
theorem nextOr_mem {xs : List α} {x d : α} (hd : d ∈ xs) : nextOr xs x d ∈ xs := by
revert hd
suffices ∀ xs' : List α, (∀ x ∈ xs, x ∈ xs') → d ∈ xs' → nextOr xs x d ∈ xs' by
exact this xs fun _ => id
intro xs' hxs' hd
induction' xs with y ys ih
· exact hd
cases' ys with z zs
· exact hd
rw [nextOr]
split_ifs with h
· exact hxs' _ (mem_cons_of_mem _ (mem_cons_self _ _))
· exact ih fun _ h => hxs' _ (mem_cons_of_mem _ h)
#align list.next_or_mem List.nextOr_mem
def next (l : List α) (x : α) (h : x ∈ l) : α :=
nextOr l x (l.get ⟨0, length_pos_of_mem h⟩)
#align list.next List.next
def prev : ∀ l : List α, ∀ x ∈ l, α
| [], _, h => by simp at h
| [y], _, _ => y
| y :: z :: xs, x, h =>
if hx : x = y then getLast (z :: xs) (cons_ne_nil _ _)
else if x = z then y else prev (z :: xs) x (by simpa [hx] using h)
#align list.prev List.prev
variable (l : List α) (x : α)
@[simp]
theorem next_singleton (x y : α) (h : x ∈ [y]) : next [y] x h = y :=
rfl
#align list.next_singleton List.next_singleton
@[simp]
theorem prev_singleton (x y : α) (h : x ∈ [y]) : prev [y] x h = y :=
rfl
#align list.prev_singleton List.prev_singleton
theorem next_cons_cons_eq' (y z : α) (h : x ∈ y :: z :: l) (hx : x = y) :
next (y :: z :: l) x h = z := by rw [next, nextOr, if_pos hx]
#align list.next_cons_cons_eq' List.next_cons_cons_eq'
@[simp]
theorem next_cons_cons_eq (z : α) (h : x ∈ x :: z :: l) : next (x :: z :: l) x h = z :=
next_cons_cons_eq' l x x z h rfl
#align list.next_cons_cons_eq List.next_cons_cons_eq
theorem next_ne_head_ne_getLast (h : x ∈ l) (y : α) (h : x ∈ y :: l) (hy : x ≠ y)
(hx : x ≠ getLast (y :: l) (cons_ne_nil _ _)) :
next (y :: l) x h = next l x (by simpa [hy] using h) := by
rw [next, next, nextOr_cons_of_ne _ _ _ _ hy, nextOr_eq_nextOr_of_mem_of_ne]
· rwa [getLast_cons] at hx
exact ne_nil_of_mem (by assumption)
· rwa [getLast_cons] at hx
#align list.next_ne_head_ne_last List.next_ne_head_ne_getLast
theorem next_cons_concat (y : α) (hy : x ≠ y) (hx : x ∉ l)
(h : x ∈ y :: l ++ [x] := mem_append_right _ (mem_singleton_self x)) :
next (y :: l ++ [x]) x h = y := by
rw [next, nextOr_concat]
· rfl
· simp [hy, hx]
#align list.next_cons_concat List.next_cons_concat
theorem next_getLast_cons (h : x ∈ l) (y : α) (h : x ∈ y :: l) (hy : x ≠ y)
(hx : x = getLast (y :: l) (cons_ne_nil _ _)) (hl : Nodup l) : next (y :: l) x h = y := by
rw [next, get, ← dropLast_append_getLast (cons_ne_nil y l), hx, nextOr_concat]
subst hx
intro H
obtain ⟨⟨_ | k, hk⟩, hk'⟩ := get_of_mem H
· rw [← Option.some_inj] at hk'
rw [← get?_eq_get, dropLast_eq_take, get?_take, get?_zero, head?_cons,
Option.some_inj] at hk'
· exact hy (Eq.symm hk')
rw [length_cons, Nat.pred_succ]
exact length_pos_of_mem (by assumption)
suffices k + 1 = l.length by simp [this] at hk
cases' l with hd tl
· simp at hk
· rw [nodup_iff_injective_get] at hl
rw [length, Nat.succ_inj']
refine Fin.val_eq_of_eq <| @hl ⟨k, Nat.lt_of_succ_lt <| by simpa using hk⟩
⟨tl.length, by simp⟩ ?_
rw [← Option.some_inj] at hk'
rw [← get?_eq_get, dropLast_eq_take, get?_take, get?, get?_eq_get, Option.some_inj] at hk'
· rw [hk']
simp only [getLast_eq_get, length_cons, ge_iff_le, Nat.succ_sub_succ_eq_sub,
nonpos_iff_eq_zero, add_eq_zero_iff, and_false, Nat.sub_zero, get_cons_succ]
simpa using hk
#align list.next_last_cons List.next_getLast_cons
| Mathlib/Data/List/Cycle.lean | 207 | 208 | theorem prev_getLast_cons' (y : α) (hxy : x ∈ y :: l) (hx : x = y) :
prev (y :: l) x hxy = getLast (y :: l) (cons_ne_nil _ _) := by | cases l <;> simp [prev, hx]
|
import Mathlib.Analysis.SpecialFunctions.Pow.Real
#align_import analysis.special_functions.pow.nnreal from "leanprover-community/mathlib"@"4fa54b337f7d52805480306db1b1439c741848c8"
noncomputable section
open scoped Classical
open Real NNReal ENNReal ComplexConjugate
open Finset Function Set
namespace NNReal
variable {w x y z : ℝ}
noncomputable def rpow (x : ℝ≥0) (y : ℝ) : ℝ≥0 :=
⟨(x : ℝ) ^ y, Real.rpow_nonneg x.2 y⟩
#align nnreal.rpow NNReal.rpow
noncomputable instance : Pow ℝ≥0 ℝ :=
⟨rpow⟩
@[simp]
theorem rpow_eq_pow (x : ℝ≥0) (y : ℝ) : rpow x y = x ^ y :=
rfl
#align nnreal.rpow_eq_pow NNReal.rpow_eq_pow
@[simp, norm_cast]
theorem coe_rpow (x : ℝ≥0) (y : ℝ) : ((x ^ y : ℝ≥0) : ℝ) = (x : ℝ) ^ y :=
rfl
#align nnreal.coe_rpow NNReal.coe_rpow
@[simp]
theorem rpow_zero (x : ℝ≥0) : x ^ (0 : ℝ) = 1 :=
NNReal.eq <| Real.rpow_zero _
#align nnreal.rpow_zero NNReal.rpow_zero
@[simp]
theorem rpow_eq_zero_iff {x : ℝ≥0} {y : ℝ} : x ^ y = 0 ↔ x = 0 ∧ y ≠ 0 := by
rw [← NNReal.coe_inj, coe_rpow, ← NNReal.coe_eq_zero]
exact Real.rpow_eq_zero_iff_of_nonneg x.2
#align nnreal.rpow_eq_zero_iff NNReal.rpow_eq_zero_iff
@[simp]
theorem zero_rpow {x : ℝ} (h : x ≠ 0) : (0 : ℝ≥0) ^ x = 0 :=
NNReal.eq <| Real.zero_rpow h
#align nnreal.zero_rpow NNReal.zero_rpow
@[simp]
theorem rpow_one (x : ℝ≥0) : x ^ (1 : ℝ) = x :=
NNReal.eq <| Real.rpow_one _
#align nnreal.rpow_one NNReal.rpow_one
@[simp]
theorem one_rpow (x : ℝ) : (1 : ℝ≥0) ^ x = 1 :=
NNReal.eq <| Real.one_rpow _
#align nnreal.one_rpow NNReal.one_rpow
theorem rpow_add {x : ℝ≥0} (hx : x ≠ 0) (y z : ℝ) : x ^ (y + z) = x ^ y * x ^ z :=
NNReal.eq <| Real.rpow_add (pos_iff_ne_zero.2 hx) _ _
#align nnreal.rpow_add NNReal.rpow_add
theorem rpow_add' (x : ℝ≥0) {y z : ℝ} (h : y + z ≠ 0) : x ^ (y + z) = x ^ y * x ^ z :=
NNReal.eq <| Real.rpow_add' x.2 h
#align nnreal.rpow_add' NNReal.rpow_add'
lemma rpow_of_add_eq (x : ℝ≥0) (hw : w ≠ 0) (h : y + z = w) : x ^ w = x ^ y * x ^ z := by
rw [← h, rpow_add']; rwa [h]
theorem rpow_mul (x : ℝ≥0) (y z : ℝ) : x ^ (y * z) = (x ^ y) ^ z :=
NNReal.eq <| Real.rpow_mul x.2 y z
#align nnreal.rpow_mul NNReal.rpow_mul
theorem rpow_neg (x : ℝ≥0) (y : ℝ) : x ^ (-y) = (x ^ y)⁻¹ :=
NNReal.eq <| Real.rpow_neg x.2 _
#align nnreal.rpow_neg NNReal.rpow_neg
theorem rpow_neg_one (x : ℝ≥0) : x ^ (-1 : ℝ) = x⁻¹ := by simp [rpow_neg]
#align nnreal.rpow_neg_one NNReal.rpow_neg_one
theorem rpow_sub {x : ℝ≥0} (hx : x ≠ 0) (y z : ℝ) : x ^ (y - z) = x ^ y / x ^ z :=
NNReal.eq <| Real.rpow_sub (pos_iff_ne_zero.2 hx) y z
#align nnreal.rpow_sub NNReal.rpow_sub
theorem rpow_sub' (x : ℝ≥0) {y z : ℝ} (h : y - z ≠ 0) : x ^ (y - z) = x ^ y / x ^ z :=
NNReal.eq <| Real.rpow_sub' x.2 h
#align nnreal.rpow_sub' NNReal.rpow_sub'
theorem rpow_inv_rpow_self {y : ℝ} (hy : y ≠ 0) (x : ℝ≥0) : (x ^ y) ^ (1 / y) = x := by
field_simp [← rpow_mul]
#align nnreal.rpow_inv_rpow_self NNReal.rpow_inv_rpow_self
theorem rpow_self_rpow_inv {y : ℝ} (hy : y ≠ 0) (x : ℝ≥0) : (x ^ (1 / y)) ^ y = x := by
field_simp [← rpow_mul]
#align nnreal.rpow_self_rpow_inv NNReal.rpow_self_rpow_inv
theorem inv_rpow (x : ℝ≥0) (y : ℝ) : x⁻¹ ^ y = (x ^ y)⁻¹ :=
NNReal.eq <| Real.inv_rpow x.2 y
#align nnreal.inv_rpow NNReal.inv_rpow
theorem div_rpow (x y : ℝ≥0) (z : ℝ) : (x / y) ^ z = x ^ z / y ^ z :=
NNReal.eq <| Real.div_rpow x.2 y.2 z
#align nnreal.div_rpow NNReal.div_rpow
theorem sqrt_eq_rpow (x : ℝ≥0) : sqrt x = x ^ (1 / (2 : ℝ)) := by
refine NNReal.eq ?_
push_cast
exact Real.sqrt_eq_rpow x.1
#align nnreal.sqrt_eq_rpow NNReal.sqrt_eq_rpow
@[simp, norm_cast]
theorem rpow_natCast (x : ℝ≥0) (n : ℕ) : x ^ (n : ℝ) = x ^ n :=
NNReal.eq <| by simpa only [coe_rpow, coe_pow] using Real.rpow_natCast x n
#align nnreal.rpow_nat_cast NNReal.rpow_natCast
@[deprecated (since := "2024-04-17")]
alias rpow_nat_cast := rpow_natCast
@[simp]
lemma rpow_ofNat (x : ℝ≥0) (n : ℕ) [n.AtLeastTwo] :
x ^ (no_index (OfNat.ofNat n) : ℝ) = x ^ (OfNat.ofNat n : ℕ) :=
rpow_natCast x n
theorem rpow_two (x : ℝ≥0) : x ^ (2 : ℝ) = x ^ 2 := rpow_ofNat x 2
#align nnreal.rpow_two NNReal.rpow_two
theorem mul_rpow {x y : ℝ≥0} {z : ℝ} : (x * y) ^ z = x ^ z * y ^ z :=
NNReal.eq <| Real.mul_rpow x.2 y.2
#align nnreal.mul_rpow NNReal.mul_rpow
@[simps]
def rpowMonoidHom (r : ℝ) : ℝ≥0 →* ℝ≥0 where
toFun := (· ^ r)
map_one' := one_rpow _
map_mul' _x _y := mul_rpow
theorem list_prod_map_rpow (l : List ℝ≥0) (r : ℝ) :
(l.map (· ^ r)).prod = l.prod ^ r :=
l.prod_hom (rpowMonoidHom r)
theorem list_prod_map_rpow' {ι} (l : List ι) (f : ι → ℝ≥0) (r : ℝ) :
(l.map (f · ^ r)).prod = (l.map f).prod ^ r := by
rw [← list_prod_map_rpow, List.map_map]; rfl
lemma multiset_prod_map_rpow {ι} (s : Multiset ι) (f : ι → ℝ≥0) (r : ℝ) :
(s.map (f · ^ r)).prod = (s.map f).prod ^ r :=
s.prod_hom' (rpowMonoidHom r) _
lemma finset_prod_rpow {ι} (s : Finset ι) (f : ι → ℝ≥0) (r : ℝ) :
(∏ i ∈ s, f i ^ r) = (∏ i ∈ s, f i) ^ r :=
multiset_prod_map_rpow _ _ _
-- note: these don't really belong here, but they're much easier to prove in terms of the above
namespace ENNReal
noncomputable def rpow : ℝ≥0∞ → ℝ → ℝ≥0∞
| some x, y => if x = 0 ∧ y < 0 then ⊤ else (x ^ y : ℝ≥0)
| none, y => if 0 < y then ⊤ else if y = 0 then 1 else 0
#align ennreal.rpow ENNReal.rpow
noncomputable instance : Pow ℝ≥0∞ ℝ :=
⟨rpow⟩
@[simp]
theorem rpow_eq_pow (x : ℝ≥0∞) (y : ℝ) : rpow x y = x ^ y :=
rfl
#align ennreal.rpow_eq_pow ENNReal.rpow_eq_pow
@[simp]
theorem rpow_zero {x : ℝ≥0∞} : x ^ (0 : ℝ) = 1 := by
cases x <;>
· dsimp only [(· ^ ·), Pow.pow, rpow]
simp [lt_irrefl]
#align ennreal.rpow_zero ENNReal.rpow_zero
theorem top_rpow_def (y : ℝ) : (⊤ : ℝ≥0∞) ^ y = if 0 < y then ⊤ else if y = 0 then 1 else 0 :=
rfl
#align ennreal.top_rpow_def ENNReal.top_rpow_def
@[simp]
theorem top_rpow_of_pos {y : ℝ} (h : 0 < y) : (⊤ : ℝ≥0∞) ^ y = ⊤ := by simp [top_rpow_def, h]
#align ennreal.top_rpow_of_pos ENNReal.top_rpow_of_pos
@[simp]
theorem top_rpow_of_neg {y : ℝ} (h : y < 0) : (⊤ : ℝ≥0∞) ^ y = 0 := by
simp [top_rpow_def, asymm h, ne_of_lt h]
#align ennreal.top_rpow_of_neg ENNReal.top_rpow_of_neg
@[simp]
theorem zero_rpow_of_pos {y : ℝ} (h : 0 < y) : (0 : ℝ≥0∞) ^ y = 0 := by
rw [← ENNReal.coe_zero, ← ENNReal.some_eq_coe]
dsimp only [(· ^ ·), rpow, Pow.pow]
simp [h, asymm h, ne_of_gt h]
#align ennreal.zero_rpow_of_pos ENNReal.zero_rpow_of_pos
@[simp]
theorem zero_rpow_of_neg {y : ℝ} (h : y < 0) : (0 : ℝ≥0∞) ^ y = ⊤ := by
rw [← ENNReal.coe_zero, ← ENNReal.some_eq_coe]
dsimp only [(· ^ ·), rpow, Pow.pow]
simp [h, ne_of_gt h]
#align ennreal.zero_rpow_of_neg ENNReal.zero_rpow_of_neg
theorem zero_rpow_def (y : ℝ) : (0 : ℝ≥0∞) ^ y = if 0 < y then 0 else if y = 0 then 1 else ⊤ := by
rcases lt_trichotomy (0 : ℝ) y with (H | rfl | H)
· simp [H, ne_of_gt, zero_rpow_of_pos, lt_irrefl]
· simp [lt_irrefl]
· simp [H, asymm H, ne_of_lt, zero_rpow_of_neg]
#align ennreal.zero_rpow_def ENNReal.zero_rpow_def
@[simp]
theorem zero_rpow_mul_self (y : ℝ) : (0 : ℝ≥0∞) ^ y * (0 : ℝ≥0∞) ^ y = (0 : ℝ≥0∞) ^ y := by
rw [zero_rpow_def]
split_ifs
exacts [zero_mul _, one_mul _, top_mul_top]
#align ennreal.zero_rpow_mul_self ENNReal.zero_rpow_mul_self
@[norm_cast]
theorem coe_rpow_of_ne_zero {x : ℝ≥0} (h : x ≠ 0) (y : ℝ) : (x : ℝ≥0∞) ^ y = (x ^ y : ℝ≥0) := by
rw [← ENNReal.some_eq_coe]
dsimp only [(· ^ ·), Pow.pow, rpow]
simp [h]
#align ennreal.coe_rpow_of_ne_zero ENNReal.coe_rpow_of_ne_zero
@[norm_cast]
theorem coe_rpow_of_nonneg (x : ℝ≥0) {y : ℝ} (h : 0 ≤ y) : (x : ℝ≥0∞) ^ y = (x ^ y : ℝ≥0) := by
by_cases hx : x = 0
· rcases le_iff_eq_or_lt.1 h with (H | H)
· simp [hx, H.symm]
· simp [hx, zero_rpow_of_pos H, NNReal.zero_rpow (ne_of_gt H)]
· exact coe_rpow_of_ne_zero hx _
#align ennreal.coe_rpow_of_nonneg ENNReal.coe_rpow_of_nonneg
theorem coe_rpow_def (x : ℝ≥0) (y : ℝ) :
(x : ℝ≥0∞) ^ y = if x = 0 ∧ y < 0 then ⊤ else ↑(x ^ y) :=
rfl
#align ennreal.coe_rpow_def ENNReal.coe_rpow_def
@[simp]
theorem rpow_one (x : ℝ≥0∞) : x ^ (1 : ℝ) = x := by
cases x
· exact dif_pos zero_lt_one
· change ite _ _ _ = _
simp only [NNReal.rpow_one, some_eq_coe, ite_eq_right_iff, top_ne_coe, and_imp]
exact fun _ => zero_le_one.not_lt
#align ennreal.rpow_one ENNReal.rpow_one
@[simp]
theorem one_rpow (x : ℝ) : (1 : ℝ≥0∞) ^ x = 1 := by
rw [← coe_one, coe_rpow_of_ne_zero one_ne_zero]
simp
#align ennreal.one_rpow ENNReal.one_rpow
@[simp]
theorem rpow_eq_zero_iff {x : ℝ≥0∞} {y : ℝ} : x ^ y = 0 ↔ x = 0 ∧ 0 < y ∨ x = ⊤ ∧ y < 0 := by
cases' x with x
· rcases lt_trichotomy y 0 with (H | H | H) <;>
simp [H, top_rpow_of_neg, top_rpow_of_pos, le_of_lt]
· by_cases h : x = 0
· rcases lt_trichotomy y 0 with (H | H | H) <;>
simp [h, H, zero_rpow_of_neg, zero_rpow_of_pos, le_of_lt]
· simp [coe_rpow_of_ne_zero h, h]
#align ennreal.rpow_eq_zero_iff ENNReal.rpow_eq_zero_iff
lemma rpow_eq_zero_iff_of_pos {x : ℝ≥0∞} {y : ℝ} (hy : 0 < y) : x ^ y = 0 ↔ x = 0 := by
simp [hy, hy.not_lt]
@[simp]
theorem rpow_eq_top_iff {x : ℝ≥0∞} {y : ℝ} : x ^ y = ⊤ ↔ x = 0 ∧ y < 0 ∨ x = ⊤ ∧ 0 < y := by
cases' x with x
· rcases lt_trichotomy y 0 with (H | H | H) <;>
simp [H, top_rpow_of_neg, top_rpow_of_pos, le_of_lt]
· by_cases h : x = 0
· rcases lt_trichotomy y 0 with (H | H | H) <;>
simp [h, H, zero_rpow_of_neg, zero_rpow_of_pos, le_of_lt]
· simp [coe_rpow_of_ne_zero h, h]
#align ennreal.rpow_eq_top_iff ENNReal.rpow_eq_top_iff
theorem rpow_eq_top_iff_of_pos {x : ℝ≥0∞} {y : ℝ} (hy : 0 < y) : x ^ y = ⊤ ↔ x = ⊤ := by
simp [rpow_eq_top_iff, hy, asymm hy]
#align ennreal.rpow_eq_top_iff_of_pos ENNReal.rpow_eq_top_iff_of_pos
lemma rpow_lt_top_iff_of_pos {x : ℝ≥0∞} {y : ℝ} (hy : 0 < y) : x ^ y < ∞ ↔ x < ∞ := by
simp only [lt_top_iff_ne_top, Ne, rpow_eq_top_iff_of_pos hy]
theorem rpow_eq_top_of_nonneg (x : ℝ≥0∞) {y : ℝ} (hy0 : 0 ≤ y) : x ^ y = ⊤ → x = ⊤ := by
rw [ENNReal.rpow_eq_top_iff]
rintro (h|h)
· exfalso
rw [lt_iff_not_ge] at h
exact h.right hy0
· exact h.left
#align ennreal.rpow_eq_top_of_nonneg ENNReal.rpow_eq_top_of_nonneg
theorem rpow_ne_top_of_nonneg {x : ℝ≥0∞} {y : ℝ} (hy0 : 0 ≤ y) (h : x ≠ ⊤) : x ^ y ≠ ⊤ :=
mt (ENNReal.rpow_eq_top_of_nonneg x hy0) h
#align ennreal.rpow_ne_top_of_nonneg ENNReal.rpow_ne_top_of_nonneg
theorem rpow_lt_top_of_nonneg {x : ℝ≥0∞} {y : ℝ} (hy0 : 0 ≤ y) (h : x ≠ ⊤) : x ^ y < ⊤ :=
lt_top_iff_ne_top.mpr (ENNReal.rpow_ne_top_of_nonneg hy0 h)
#align ennreal.rpow_lt_top_of_nonneg ENNReal.rpow_lt_top_of_nonneg
theorem rpow_add {x : ℝ≥0∞} (y z : ℝ) (hx : x ≠ 0) (h'x : x ≠ ⊤) : x ^ (y + z) = x ^ y * x ^ z := by
cases' x with x
· exact (h'x rfl).elim
have : x ≠ 0 := fun h => by simp [h] at hx
simp [coe_rpow_of_ne_zero this, NNReal.rpow_add this]
#align ennreal.rpow_add ENNReal.rpow_add
theorem rpow_neg (x : ℝ≥0∞) (y : ℝ) : x ^ (-y) = (x ^ y)⁻¹ := by
cases' x with x
· rcases lt_trichotomy y 0 with (H | H | H) <;>
simp [top_rpow_of_pos, top_rpow_of_neg, H, neg_pos.mpr]
· by_cases h : x = 0
· rcases lt_trichotomy y 0 with (H | H | H) <;>
simp [h, zero_rpow_of_pos, zero_rpow_of_neg, H, neg_pos.mpr]
· have A : x ^ y ≠ 0 := by simp [h]
simp [coe_rpow_of_ne_zero h, ← coe_inv A, NNReal.rpow_neg]
#align ennreal.rpow_neg ENNReal.rpow_neg
theorem rpow_sub {x : ℝ≥0∞} (y z : ℝ) (hx : x ≠ 0) (h'x : x ≠ ⊤) : x ^ (y - z) = x ^ y / x ^ z := by
rw [sub_eq_add_neg, rpow_add _ _ hx h'x, rpow_neg, div_eq_mul_inv]
#align ennreal.rpow_sub ENNReal.rpow_sub
theorem rpow_neg_one (x : ℝ≥0∞) : x ^ (-1 : ℝ) = x⁻¹ := by simp [rpow_neg]
#align ennreal.rpow_neg_one ENNReal.rpow_neg_one
theorem rpow_mul (x : ℝ≥0∞) (y z : ℝ) : x ^ (y * z) = (x ^ y) ^ z := by
cases' x with x
· rcases lt_trichotomy y 0 with (Hy | Hy | Hy) <;>
rcases lt_trichotomy z 0 with (Hz | Hz | Hz) <;>
simp [Hy, Hz, zero_rpow_of_neg, zero_rpow_of_pos, top_rpow_of_neg, top_rpow_of_pos,
mul_pos_of_neg_of_neg, mul_neg_of_neg_of_pos, mul_neg_of_pos_of_neg]
· by_cases h : x = 0
· rcases lt_trichotomy y 0 with (Hy | Hy | Hy) <;>
rcases lt_trichotomy z 0 with (Hz | Hz | Hz) <;>
simp [h, Hy, Hz, zero_rpow_of_neg, zero_rpow_of_pos, top_rpow_of_neg, top_rpow_of_pos,
mul_pos_of_neg_of_neg, mul_neg_of_neg_of_pos, mul_neg_of_pos_of_neg]
· have : x ^ y ≠ 0 := by simp [h]
simp [coe_rpow_of_ne_zero h, coe_rpow_of_ne_zero this, NNReal.rpow_mul]
#align ennreal.rpow_mul ENNReal.rpow_mul
@[simp, norm_cast]
theorem rpow_natCast (x : ℝ≥0∞) (n : ℕ) : x ^ (n : ℝ) = x ^ n := by
cases x
· cases n <;> simp [top_rpow_of_pos (Nat.cast_add_one_pos _), top_pow (Nat.succ_pos _)]
· simp [coe_rpow_of_nonneg _ (Nat.cast_nonneg n)]
#align ennreal.rpow_nat_cast ENNReal.rpow_natCast
@[deprecated (since := "2024-04-17")]
alias rpow_nat_cast := rpow_natCast
@[simp]
lemma rpow_ofNat (x : ℝ≥0∞) (n : ℕ) [n.AtLeastTwo] :
x ^ (no_index (OfNat.ofNat n) : ℝ) = x ^ (OfNat.ofNat n) :=
rpow_natCast x n
@[simp, norm_cast]
lemma rpow_intCast (x : ℝ≥0∞) (n : ℤ) : x ^ (n : ℝ) = x ^ n := by
cases n <;> simp only [Int.ofNat_eq_coe, Int.cast_natCast, rpow_natCast, zpow_natCast,
Int.cast_negSucc, rpow_neg, zpow_negSucc]
@[deprecated (since := "2024-04-17")]
alias rpow_int_cast := rpow_intCast
theorem rpow_two (x : ℝ≥0∞) : x ^ (2 : ℝ) = x ^ 2 := rpow_ofNat x 2
#align ennreal.rpow_two ENNReal.rpow_two
theorem mul_rpow_eq_ite (x y : ℝ≥0∞) (z : ℝ) :
(x * y) ^ z = if (x = 0 ∧ y = ⊤ ∨ x = ⊤ ∧ y = 0) ∧ z < 0 then ⊤ else x ^ z * y ^ z := by
rcases eq_or_ne z 0 with (rfl | hz); · simp
replace hz := hz.lt_or_lt
wlog hxy : x ≤ y
· convert this y x z hz (le_of_not_le hxy) using 2 <;> simp only [mul_comm, and_comm, or_comm]
rcases eq_or_ne x 0 with (rfl | hx0)
· induction y <;> cases' hz with hz hz <;> simp [*, hz.not_lt]
rcases eq_or_ne y 0 with (rfl | hy0)
· exact (hx0 (bot_unique hxy)).elim
induction x
· cases' hz with hz hz <;> simp [hz, top_unique hxy]
induction y
· rw [ne_eq, coe_eq_zero] at hx0
cases' hz with hz hz <;> simp [*]
simp only [*, false_and_iff, and_false_iff, false_or_iff, if_false]
norm_cast at *
rw [coe_rpow_of_ne_zero (mul_ne_zero hx0 hy0), NNReal.mul_rpow]
norm_cast
#align ennreal.mul_rpow_eq_ite ENNReal.mul_rpow_eq_ite
theorem mul_rpow_of_ne_top {x y : ℝ≥0∞} (hx : x ≠ ⊤) (hy : y ≠ ⊤) (z : ℝ) :
(x * y) ^ z = x ^ z * y ^ z := by simp [*, mul_rpow_eq_ite]
#align ennreal.mul_rpow_of_ne_top ENNReal.mul_rpow_of_ne_top
@[norm_cast]
theorem coe_mul_rpow (x y : ℝ≥0) (z : ℝ) : ((x : ℝ≥0∞) * y) ^ z = (x : ℝ≥0∞) ^ z * (y : ℝ≥0∞) ^ z :=
mul_rpow_of_ne_top coe_ne_top coe_ne_top z
#align ennreal.coe_mul_rpow ENNReal.coe_mul_rpow
theorem prod_coe_rpow {ι} (s : Finset ι) (f : ι → ℝ≥0) (r : ℝ) :
∏ i ∈ s, (f i : ℝ≥0∞) ^ r = ((∏ i ∈ s, f i : ℝ≥0) : ℝ≥0∞) ^ r := by
induction s using Finset.induction with
| empty => simp
| insert hi ih => simp_rw [prod_insert hi, ih, ← coe_mul_rpow, coe_mul]
theorem mul_rpow_of_ne_zero {x y : ℝ≥0∞} (hx : x ≠ 0) (hy : y ≠ 0) (z : ℝ) :
(x * y) ^ z = x ^ z * y ^ z := by simp [*, mul_rpow_eq_ite]
#align ennreal.mul_rpow_of_ne_zero ENNReal.mul_rpow_of_ne_zero
theorem mul_rpow_of_nonneg (x y : ℝ≥0∞) {z : ℝ} (hz : 0 ≤ z) : (x * y) ^ z = x ^ z * y ^ z := by
simp [hz.not_lt, mul_rpow_eq_ite]
#align ennreal.mul_rpow_of_nonneg ENNReal.mul_rpow_of_nonneg
theorem prod_rpow_of_ne_top {ι} {s : Finset ι} {f : ι → ℝ≥0∞} (hf : ∀ i ∈ s, f i ≠ ∞) (r : ℝ) :
∏ i ∈ s, f i ^ r = (∏ i ∈ s, f i) ^ r := by
induction s using Finset.induction with
| empty => simp
| @insert i s hi ih =>
have h2f : ∀ i ∈ s, f i ≠ ∞ := fun i hi ↦ hf i <| mem_insert_of_mem hi
rw [prod_insert hi, prod_insert hi, ih h2f, ← mul_rpow_of_ne_top <| hf i <| mem_insert_self ..]
apply prod_lt_top h2f |>.ne
theorem prod_rpow_of_nonneg {ι} {s : Finset ι} {f : ι → ℝ≥0∞} {r : ℝ} (hr : 0 ≤ r) :
∏ i ∈ s, f i ^ r = (∏ i ∈ s, f i) ^ r := by
induction s using Finset.induction with
| empty => simp
| insert hi ih => simp_rw [prod_insert hi, ih, ← mul_rpow_of_nonneg _ _ hr]
theorem inv_rpow (x : ℝ≥0∞) (y : ℝ) : x⁻¹ ^ y = (x ^ y)⁻¹ := by
rcases eq_or_ne y 0 with (rfl | hy); · simp only [rpow_zero, inv_one]
replace hy := hy.lt_or_lt
rcases eq_or_ne x 0 with (rfl | h0); · cases hy <;> simp [*]
rcases eq_or_ne x ⊤ with (rfl | h_top); · cases hy <;> simp [*]
apply ENNReal.eq_inv_of_mul_eq_one_left
rw [← mul_rpow_of_ne_zero (ENNReal.inv_ne_zero.2 h_top) h0, ENNReal.inv_mul_cancel h0 h_top,
one_rpow]
#align ennreal.inv_rpow ENNReal.inv_rpow
theorem div_rpow_of_nonneg (x y : ℝ≥0∞) {z : ℝ} (hz : 0 ≤ z) : (x / y) ^ z = x ^ z / y ^ z := by
rw [div_eq_mul_inv, mul_rpow_of_nonneg _ _ hz, inv_rpow, div_eq_mul_inv]
#align ennreal.div_rpow_of_nonneg ENNReal.div_rpow_of_nonneg
theorem strictMono_rpow_of_pos {z : ℝ} (h : 0 < z) : StrictMono fun x : ℝ≥0∞ => x ^ z := by
intro x y hxy
lift x to ℝ≥0 using ne_top_of_lt hxy
rcases eq_or_ne y ∞ with (rfl | hy)
· simp only [top_rpow_of_pos h, coe_rpow_of_nonneg _ h.le, coe_lt_top]
· lift y to ℝ≥0 using hy
simp only [coe_rpow_of_nonneg _ h.le, NNReal.rpow_lt_rpow (coe_lt_coe.1 hxy) h, coe_lt_coe]
#align ennreal.strict_mono_rpow_of_pos ENNReal.strictMono_rpow_of_pos
theorem monotone_rpow_of_nonneg {z : ℝ} (h : 0 ≤ z) : Monotone fun x : ℝ≥0∞ => x ^ z :=
h.eq_or_lt.elim (fun h0 => h0 ▸ by simp only [rpow_zero, monotone_const]) fun h0 =>
(strictMono_rpow_of_pos h0).monotone
#align ennreal.monotone_rpow_of_nonneg ENNReal.monotone_rpow_of_nonneg
@[simps! apply]
def orderIsoRpow (y : ℝ) (hy : 0 < y) : ℝ≥0∞ ≃o ℝ≥0∞ :=
(strictMono_rpow_of_pos hy).orderIsoOfRightInverse (fun x => x ^ y) (fun x => x ^ (1 / y))
fun x => by
dsimp
rw [← rpow_mul, one_div_mul_cancel hy.ne.symm, rpow_one]
#align ennreal.order_iso_rpow ENNReal.orderIsoRpow
theorem orderIsoRpow_symm_apply (y : ℝ) (hy : 0 < y) :
(orderIsoRpow y hy).symm = orderIsoRpow (1 / y) (one_div_pos.2 hy) := by
simp only [orderIsoRpow, one_div_one_div]
rfl
#align ennreal.order_iso_rpow_symm_apply ENNReal.orderIsoRpow_symm_apply
@[gcongr] theorem rpow_le_rpow {x y : ℝ≥0∞} {z : ℝ} (h₁ : x ≤ y) (h₂ : 0 ≤ z) : x ^ z ≤ y ^ z :=
monotone_rpow_of_nonneg h₂ h₁
#align ennreal.rpow_le_rpow ENNReal.rpow_le_rpow
@[gcongr] theorem rpow_lt_rpow {x y : ℝ≥0∞} {z : ℝ} (h₁ : x < y) (h₂ : 0 < z) : x ^ z < y ^ z :=
strictMono_rpow_of_pos h₂ h₁
#align ennreal.rpow_lt_rpow ENNReal.rpow_lt_rpow
theorem rpow_le_rpow_iff {x y : ℝ≥0∞} {z : ℝ} (hz : 0 < z) : x ^ z ≤ y ^ z ↔ x ≤ y :=
(strictMono_rpow_of_pos hz).le_iff_le
#align ennreal.rpow_le_rpow_iff ENNReal.rpow_le_rpow_iff
theorem rpow_lt_rpow_iff {x y : ℝ≥0∞} {z : ℝ} (hz : 0 < z) : x ^ z < y ^ z ↔ x < y :=
(strictMono_rpow_of_pos hz).lt_iff_lt
#align ennreal.rpow_lt_rpow_iff ENNReal.rpow_lt_rpow_iff
theorem le_rpow_one_div_iff {x y : ℝ≥0∞} {z : ℝ} (hz : 0 < z) : x ≤ y ^ (1 / z) ↔ x ^ z ≤ y := by
nth_rw 1 [← rpow_one x]
nth_rw 1 [← @_root_.mul_inv_cancel _ _ z hz.ne']
rw [rpow_mul, ← one_div, @rpow_le_rpow_iff _ _ (1 / z) (by simp [hz])]
#align ennreal.le_rpow_one_div_iff ENNReal.le_rpow_one_div_iff
theorem lt_rpow_one_div_iff {x y : ℝ≥0∞} {z : ℝ} (hz : 0 < z) : x < y ^ (1 / z) ↔ x ^ z < y := by
nth_rw 1 [← rpow_one x]
nth_rw 1 [← @_root_.mul_inv_cancel _ _ z (ne_of_lt hz).symm]
rw [rpow_mul, ← one_div, @rpow_lt_rpow_iff _ _ (1 / z) (by simp [hz])]
#align ennreal.lt_rpow_one_div_iff ENNReal.lt_rpow_one_div_iff
theorem rpow_one_div_le_iff {x y : ℝ≥0∞} {z : ℝ} (hz : 0 < z) : x ^ (1 / z) ≤ y ↔ x ≤ y ^ z := by
nth_rw 1 [← ENNReal.rpow_one y]
nth_rw 2 [← @_root_.mul_inv_cancel _ _ z hz.ne.symm]
rw [ENNReal.rpow_mul, ← one_div, ENNReal.rpow_le_rpow_iff (one_div_pos.2 hz)]
#align ennreal.rpow_one_div_le_iff ENNReal.rpow_one_div_le_iff
theorem rpow_lt_rpow_of_exponent_lt {x : ℝ≥0∞} {y z : ℝ} (hx : 1 < x) (hx' : x ≠ ⊤) (hyz : y < z) :
x ^ y < x ^ z := by
lift x to ℝ≥0 using hx'
rw [one_lt_coe_iff] at hx
simp [coe_rpow_of_ne_zero (ne_of_gt (lt_trans zero_lt_one hx)),
NNReal.rpow_lt_rpow_of_exponent_lt hx hyz]
#align ennreal.rpow_lt_rpow_of_exponent_lt ENNReal.rpow_lt_rpow_of_exponent_lt
@[gcongr] theorem rpow_le_rpow_of_exponent_le {x : ℝ≥0∞} {y z : ℝ} (hx : 1 ≤ x) (hyz : y ≤ z) :
x ^ y ≤ x ^ z := by
cases x
· rcases lt_trichotomy y 0 with (Hy | Hy | Hy) <;>
rcases lt_trichotomy z 0 with (Hz | Hz | Hz) <;>
simp [Hy, Hz, top_rpow_of_neg, top_rpow_of_pos, le_refl] <;>
linarith
· simp only [one_le_coe_iff, some_eq_coe] at hx
simp [coe_rpow_of_ne_zero (ne_of_gt (lt_of_lt_of_le zero_lt_one hx)),
NNReal.rpow_le_rpow_of_exponent_le hx hyz]
#align ennreal.rpow_le_rpow_of_exponent_le ENNReal.rpow_le_rpow_of_exponent_le
theorem rpow_lt_rpow_of_exponent_gt {x : ℝ≥0∞} {y z : ℝ} (hx0 : 0 < x) (hx1 : x < 1) (hyz : z < y) :
x ^ y < x ^ z := by
lift x to ℝ≥0 using ne_of_lt (lt_of_lt_of_le hx1 le_top)
simp only [coe_lt_one_iff, coe_pos] at hx0 hx1
simp [coe_rpow_of_ne_zero (ne_of_gt hx0), NNReal.rpow_lt_rpow_of_exponent_gt hx0 hx1 hyz]
#align ennreal.rpow_lt_rpow_of_exponent_gt ENNReal.rpow_lt_rpow_of_exponent_gt
theorem rpow_le_rpow_of_exponent_ge {x : ℝ≥0∞} {y z : ℝ} (hx1 : x ≤ 1) (hyz : z ≤ y) :
x ^ y ≤ x ^ z := by
lift x to ℝ≥0 using ne_of_lt (lt_of_le_of_lt hx1 coe_lt_top)
by_cases h : x = 0
· rcases lt_trichotomy y 0 with (Hy | Hy | Hy) <;>
rcases lt_trichotomy z 0 with (Hz | Hz | Hz) <;>
simp [Hy, Hz, h, zero_rpow_of_neg, zero_rpow_of_pos, le_refl] <;>
linarith
· rw [coe_le_one_iff] at hx1
simp [coe_rpow_of_ne_zero h,
NNReal.rpow_le_rpow_of_exponent_ge (bot_lt_iff_ne_bot.mpr h) hx1 hyz]
#align ennreal.rpow_le_rpow_of_exponent_ge ENNReal.rpow_le_rpow_of_exponent_ge
theorem rpow_le_self_of_le_one {x : ℝ≥0∞} {z : ℝ} (hx : x ≤ 1) (h_one_le : 1 ≤ z) : x ^ z ≤ x := by
nth_rw 2 [← ENNReal.rpow_one x]
exact ENNReal.rpow_le_rpow_of_exponent_ge hx h_one_le
#align ennreal.rpow_le_self_of_le_one ENNReal.rpow_le_self_of_le_one
theorem le_rpow_self_of_one_le {x : ℝ≥0∞} {z : ℝ} (hx : 1 ≤ x) (h_one_le : 1 ≤ z) : x ≤ x ^ z := by
nth_rw 1 [← ENNReal.rpow_one x]
exact ENNReal.rpow_le_rpow_of_exponent_le hx h_one_le
#align ennreal.le_rpow_self_of_one_le ENNReal.le_rpow_self_of_one_le
theorem rpow_pos_of_nonneg {p : ℝ} {x : ℝ≥0∞} (hx_pos : 0 < x) (hp_nonneg : 0 ≤ p) : 0 < x ^ p := by
by_cases hp_zero : p = 0
· simp [hp_zero, zero_lt_one]
· rw [← Ne] at hp_zero
have hp_pos := lt_of_le_of_ne hp_nonneg hp_zero.symm
rw [← zero_rpow_of_pos hp_pos]
exact rpow_lt_rpow hx_pos hp_pos
#align ennreal.rpow_pos_of_nonneg ENNReal.rpow_pos_of_nonneg
theorem rpow_pos {p : ℝ} {x : ℝ≥0∞} (hx_pos : 0 < x) (hx_ne_top : x ≠ ⊤) : 0 < x ^ p := by
cases' lt_or_le 0 p with hp_pos hp_nonpos
· exact rpow_pos_of_nonneg hx_pos (le_of_lt hp_pos)
· rw [← neg_neg p, rpow_neg, ENNReal.inv_pos]
exact rpow_ne_top_of_nonneg (Right.nonneg_neg_iff.mpr hp_nonpos) hx_ne_top
#align ennreal.rpow_pos ENNReal.rpow_pos
| Mathlib/Analysis/SpecialFunctions/Pow/NNReal.lean | 798 | 801 | theorem rpow_lt_one {x : ℝ≥0∞} {z : ℝ} (hx : x < 1) (hz : 0 < z) : x ^ z < 1 := by |
lift x to ℝ≥0 using ne_of_lt (lt_of_lt_of_le hx le_top)
simp only [coe_lt_one_iff] at hx
simp [coe_rpow_of_nonneg _ (le_of_lt hz), NNReal.rpow_lt_one hx hz]
|
import Mathlib.Combinatorics.Enumerative.DoubleCounting
import Mathlib.Combinatorics.SimpleGraph.AdjMatrix
import Mathlib.Combinatorics.SimpleGraph.Basic
import Mathlib.Data.Set.Finite
#align_import combinatorics.simple_graph.strongly_regular from "leanprover-community/mathlib"@"2b35fc7bea4640cb75e477e83f32fbd538920822"
open Finset
universe u
namespace SimpleGraph
variable {V : Type u} [Fintype V] [DecidableEq V]
variable (G : SimpleGraph V) [DecidableRel G.Adj]
structure IsSRGWith (n k ℓ μ : ℕ) : Prop where
card : Fintype.card V = n
regular : G.IsRegularOfDegree k
of_adj : ∀ v w : V, G.Adj v w → Fintype.card (G.commonNeighbors v w) = ℓ
of_not_adj : Pairwise fun v w => ¬G.Adj v w → Fintype.card (G.commonNeighbors v w) = μ
set_option linter.uppercaseLean3 false in
#align simple_graph.is_SRG_with SimpleGraph.IsSRGWith
variable {G} {n k ℓ μ : ℕ}
theorem bot_strongly_regular : (⊥ : SimpleGraph V).IsSRGWith (Fintype.card V) 0 ℓ 0 where
card := rfl
regular := bot_degree
of_adj := fun v w h => h.elim
of_not_adj := fun v w _h => by
simp only [card_eq_zero, Fintype.card_ofFinset, forall_true_left, not_false_iff, bot_adj]
ext
simp [mem_commonNeighbors]
#align simple_graph.bot_strongly_regular SimpleGraph.bot_strongly_regular
theorem IsSRGWith.top :
(⊤ : SimpleGraph V).IsSRGWith (Fintype.card V) (Fintype.card V - 1) (Fintype.card V - 2) μ where
card := rfl
regular := IsRegularOfDegree.top
of_adj := fun v w h => by
rw [card_commonNeighbors_top]
exact h
of_not_adj := fun v w h h' => False.elim (h' ((top_adj v w).2 h))
set_option linter.uppercaseLean3 false in
#align simple_graph.is_SRG_with.top SimpleGraph.IsSRGWith.top
theorem IsSRGWith.card_neighborFinset_union_eq {v w : V} (h : G.IsSRGWith n k ℓ μ) :
(G.neighborFinset v ∪ G.neighborFinset w).card =
2 * k - Fintype.card (G.commonNeighbors v w) := by
apply Nat.add_right_cancel (m := Fintype.card (G.commonNeighbors v w))
rw [Nat.sub_add_cancel, ← Set.toFinset_card]
-- Porting note: Set.toFinset_inter needs workaround to use unification to solve for one of the
-- instance arguments:
· simp [commonNeighbors, @Set.toFinset_inter _ _ _ _ _ _ (_),
← neighborFinset_def, Finset.card_union_add_card_inter, card_neighborFinset_eq_degree,
h.regular.degree_eq, two_mul]
· apply le_trans (card_commonNeighbors_le_degree_left _ _ _)
simp [h.regular.degree_eq, two_mul]
set_option linter.uppercaseLean3 false in
#align simple_graph.is_SRG_with.card_neighbor_finset_union_eq SimpleGraph.IsSRGWith.card_neighborFinset_union_eq
theorem IsSRGWith.card_neighborFinset_union_of_not_adj {v w : V} (h : G.IsSRGWith n k ℓ μ)
(hne : v ≠ w) (ha : ¬G.Adj v w) :
(G.neighborFinset v ∪ G.neighborFinset w).card = 2 * k - μ := by
rw [← h.of_not_adj hne ha]
apply h.card_neighborFinset_union_eq
set_option linter.uppercaseLean3 false in
#align simple_graph.is_SRG_with.card_neighbor_finset_union_of_not_adj SimpleGraph.IsSRGWith.card_neighborFinset_union_of_not_adj
| Mathlib/Combinatorics/SimpleGraph/StronglyRegular.lean | 110 | 113 | theorem IsSRGWith.card_neighborFinset_union_of_adj {v w : V} (h : G.IsSRGWith n k ℓ μ)
(ha : G.Adj v w) : (G.neighborFinset v ∪ G.neighborFinset w).card = 2 * k - ℓ := by |
rw [← h.of_adj v w ha]
apply h.card_neighborFinset_union_eq
|
import Mathlib.CategoryTheory.Sites.Sheaf
#align_import category_theory.sites.plus from "leanprover-community/mathlib"@"70fd9563a21e7b963887c9360bd29b2393e6225a"
namespace CategoryTheory.GrothendieckTopology
open CategoryTheory
open CategoryTheory.Limits
open Opposite
universe w v u
variable {C : Type u} [Category.{v} C] (J : GrothendieckTopology C)
variable {D : Type w} [Category.{max v u} D]
noncomputable section
variable [∀ (P : Cᵒᵖ ⥤ D) (X : C) (S : J.Cover X), HasMultiequalizer (S.index P)]
variable (P : Cᵒᵖ ⥤ D)
@[simps]
def diagram (X : C) : (J.Cover X)ᵒᵖ ⥤ D where
obj S := multiequalizer (S.unop.index P)
map {S _} f :=
Multiequalizer.lift _ _ (fun I => Multiequalizer.ι (S.unop.index P) (I.map f.unop)) fun I =>
Multiequalizer.condition (S.unop.index P) (I.map f.unop)
#align category_theory.grothendieck_topology.diagram CategoryTheory.GrothendieckTopology.diagram
@[simps]
def diagramPullback {X Y : C} (f : X ⟶ Y) : J.diagram P Y ⟶ (J.pullback f).op ⋙ J.diagram P X where
app S :=
Multiequalizer.lift _ _ (fun I => Multiequalizer.ι (S.unop.index P) I.base) fun I =>
Multiequalizer.condition (S.unop.index P) I.base
naturality S T f := Multiequalizer.hom_ext _ _ _ (fun I => by dsimp; simp; rfl)
#align category_theory.grothendieck_topology.diagram_pullback CategoryTheory.GrothendieckTopology.diagramPullback
@[simps]
def diagramNatTrans {P Q : Cᵒᵖ ⥤ D} (η : P ⟶ Q) (X : C) : J.diagram P X ⟶ J.diagram Q X where
app W :=
Multiequalizer.lift _ _ (fun i => Multiequalizer.ι _ _ ≫ η.app _) (fun i => by
dsimp only
erw [Category.assoc, Category.assoc, ← η.naturality, ← η.naturality,
Multiequalizer.condition_assoc]
rfl)
#align category_theory.grothendieck_topology.diagram_nat_trans CategoryTheory.GrothendieckTopology.diagramNatTrans
@[simp]
theorem diagramNatTrans_id (X : C) (P : Cᵒᵖ ⥤ D) :
J.diagramNatTrans (𝟙 P) X = 𝟙 (J.diagram P X) := by
ext : 2
refine Multiequalizer.hom_ext _ _ _ (fun i => ?_)
dsimp
simp only [limit.lift_π, Multifork.ofι_pt, Multifork.ofι_π_app, Category.id_comp]
erw [Category.comp_id]
#align category_theory.grothendieck_topology.diagram_nat_trans_id CategoryTheory.GrothendieckTopology.diagramNatTrans_id
@[simp]
theorem diagramNatTrans_zero [Preadditive D] (X : C) (P Q : Cᵒᵖ ⥤ D) :
J.diagramNatTrans (0 : P ⟶ Q) X = 0 := by
ext : 2
refine Multiequalizer.hom_ext _ _ _ (fun i => ?_)
dsimp
rw [zero_comp, Multiequalizer.lift_ι, comp_zero]
#align category_theory.grothendieck_topology.diagram_nat_trans_zero CategoryTheory.GrothendieckTopology.diagramNatTrans_zero
@[simp]
theorem diagramNatTrans_comp {P Q R : Cᵒᵖ ⥤ D} (η : P ⟶ Q) (γ : Q ⟶ R) (X : C) :
J.diagramNatTrans (η ≫ γ) X = J.diagramNatTrans η X ≫ J.diagramNatTrans γ X := by
ext : 2
refine Multiequalizer.hom_ext _ _ _ (fun i => ?_)
dsimp
simp
#align category_theory.grothendieck_topology.diagram_nat_trans_comp CategoryTheory.GrothendieckTopology.diagramNatTrans_comp
variable (D)
@[simps]
def diagramFunctor (X : C) : (Cᵒᵖ ⥤ D) ⥤ (J.Cover X)ᵒᵖ ⥤ D where
obj P := J.diagram P X
map η := J.diagramNatTrans η X
#align category_theory.grothendieck_topology.diagram_functor CategoryTheory.GrothendieckTopology.diagramFunctor
variable {D}
variable [∀ X : C, HasColimitsOfShape (J.Cover X)ᵒᵖ D]
def plusObj : Cᵒᵖ ⥤ D where
obj X := colimit (J.diagram P X.unop)
map f := colimMap (J.diagramPullback P f.unop) ≫ colimit.pre _ _
map_id := by
intro X
refine colimit.hom_ext (fun S => ?_)
dsimp
simp only [diagramPullback_app, colimit.ι_pre, ι_colimMap_assoc, Category.comp_id]
let e := S.unop.pullbackId
dsimp only [Functor.op, pullback_obj]
erw [← colimit.w _ e.inv.op, ← Category.assoc]
convert Category.id_comp (colimit.ι (diagram J P (unop X)) S)
refine Multiequalizer.hom_ext _ _ _ (fun I => ?_)
dsimp
simp only [Multiequalizer.lift_ι, Category.id_comp, Category.assoc]
dsimp [Cover.Arrow.map, Cover.Arrow.base]
cases I
congr
simp
map_comp := by
intro X Y Z f g
refine colimit.hom_ext (fun S => ?_)
dsimp
simp only [diagramPullback_app, colimit.ι_pre_assoc, colimit.ι_pre, ι_colimMap_assoc,
Category.assoc]
let e := S.unop.pullbackComp g.unop f.unop
dsimp only [Functor.op, pullback_obj]
erw [← colimit.w _ e.inv.op, ← Category.assoc, ← Category.assoc]
congr 1
refine Multiequalizer.hom_ext _ _ _ (fun I => ?_)
dsimp
simp only [Multiequalizer.lift_ι, Category.assoc]
cases I
dsimp only [Cover.Arrow.base, Cover.Arrow.map]
congr 2
simp
#align category_theory.grothendieck_topology.plus_obj CategoryTheory.GrothendieckTopology.plusObj
def plusMap {P Q : Cᵒᵖ ⥤ D} (η : P ⟶ Q) : J.plusObj P ⟶ J.plusObj Q where
app X := colimMap (J.diagramNatTrans η X.unop)
naturality := by
intro X Y f
dsimp [plusObj]
ext
simp only [diagramPullback_app, ι_colimMap, colimit.ι_pre_assoc, colimit.ι_pre,
ι_colimMap_assoc, Category.assoc]
simp_rw [← Category.assoc]
congr 1
exact Multiequalizer.hom_ext _ _ _ (fun I => by dsimp; simp)
#align category_theory.grothendieck_topology.plus_map CategoryTheory.GrothendieckTopology.plusMap
@[simp]
theorem plusMap_id (P : Cᵒᵖ ⥤ D) : J.plusMap (𝟙 P) = 𝟙 _ := by
ext : 2
dsimp only [plusMap, plusObj]
rw [J.diagramNatTrans_id, NatTrans.id_app]
ext
dsimp
simp
#align category_theory.grothendieck_topology.plus_map_id CategoryTheory.GrothendieckTopology.plusMap_id
@[simp]
theorem plusMap_zero [Preadditive D] (P Q : Cᵒᵖ ⥤ D) : J.plusMap (0 : P ⟶ Q) = 0 := by
ext : 2
refine colimit.hom_ext (fun S => ?_)
erw [comp_zero, colimit.ι_map, J.diagramNatTrans_zero, zero_comp]
#align category_theory.grothendieck_topology.plus_map_zero CategoryTheory.GrothendieckTopology.plusMap_zero
@[simp, reassoc]
theorem plusMap_comp {P Q R : Cᵒᵖ ⥤ D} (η : P ⟶ Q) (γ : Q ⟶ R) :
J.plusMap (η ≫ γ) = J.plusMap η ≫ J.plusMap γ := by
ext : 2
refine colimit.hom_ext (fun S => ?_)
simp [plusMap, J.diagramNatTrans_comp]
#align category_theory.grothendieck_topology.plus_map_comp CategoryTheory.GrothendieckTopology.plusMap_comp
variable (D)
@[simps]
def plusFunctor : (Cᵒᵖ ⥤ D) ⥤ Cᵒᵖ ⥤ D where
obj P := J.plusObj P
map η := J.plusMap η
#align category_theory.grothendieck_topology.plus_functor CategoryTheory.GrothendieckTopology.plusFunctor
variable {D}
def toPlus : P ⟶ J.plusObj P where
app X := Cover.toMultiequalizer (⊤ : J.Cover X.unop) P ≫ colimit.ι (J.diagram P X.unop) (op ⊤)
naturality := by
intro X Y f
dsimp [plusObj]
delta Cover.toMultiequalizer
simp only [diagramPullback_app, colimit.ι_pre, ι_colimMap_assoc, Category.assoc]
dsimp only [Functor.op, unop_op]
let e : (J.pullback f.unop).obj ⊤ ⟶ ⊤ := homOfLE (OrderTop.le_top _)
rw [← colimit.w _ e.op, ← Category.assoc, ← Category.assoc, ← Category.assoc]
congr 1
refine Multiequalizer.hom_ext _ _ _ (fun I => ?_)
simp only [Multiequalizer.lift_ι, Category.assoc]
dsimp [Cover.Arrow.base]
simp
#align category_theory.grothendieck_topology.to_plus CategoryTheory.GrothendieckTopology.toPlus
@[reassoc (attr := simp)]
theorem toPlus_naturality {P Q : Cᵒᵖ ⥤ D} (η : P ⟶ Q) :
η ≫ J.toPlus Q = J.toPlus _ ≫ J.plusMap η := by
ext
dsimp [toPlus, plusMap]
delta Cover.toMultiequalizer
simp only [ι_colimMap, Category.assoc]
simp_rw [← Category.assoc]
congr 1
exact Multiequalizer.hom_ext _ _ _ (fun I => by dsimp; simp)
#align category_theory.grothendieck_topology.to_plus_naturality CategoryTheory.GrothendieckTopology.toPlus_naturality
variable (D)
@[simps]
def toPlusNatTrans : 𝟭 (Cᵒᵖ ⥤ D) ⟶ J.plusFunctor D where
app P := J.toPlus P
#align category_theory.grothendieck_topology.to_plus_nat_trans CategoryTheory.GrothendieckTopology.toPlusNatTrans
variable {D}
@[simp]
theorem plusMap_toPlus : J.plusMap (J.toPlus P) = J.toPlus (J.plusObj P) := by
ext X : 2
refine colimit.hom_ext (fun S => ?_)
dsimp only [plusMap, toPlus]
let e : S.unop ⟶ ⊤ := homOfLE (OrderTop.le_top _)
rw [ι_colimMap, ← colimit.w _ e.op, ← Category.assoc, ← Category.assoc]
congr 1
refine Multiequalizer.hom_ext _ _ _ (fun I => ?_)
erw [Multiequalizer.lift_ι]
simp only [unop_op, op_unop, diagram_map, Category.assoc, limit.lift_π,
Multifork.ofι_π_app]
let ee : (J.pullback (I.map e).f).obj S.unop ⟶ ⊤ := homOfLE (OrderTop.le_top _)
erw [← colimit.w _ ee.op, ι_colimMap_assoc, colimit.ι_pre, diagramPullback_app,
← Category.assoc, ← Category.assoc]
congr 1
refine Multiequalizer.hom_ext _ _ _ (fun II => ?_)
convert (Multiequalizer.condition (S.unop.index P)
⟨_, _, _, II.f, 𝟙 _, I.f, II.f ≫ I.f, I.hf,
Sieve.downward_closed _ I.hf _, by simp⟩) using 1
· dsimp [diagram]
cases I
simp only [Category.assoc, limit.lift_π, Multifork.ofι_pt, Multifork.ofι_π_app,
Cover.Arrow.map_Y, Cover.Arrow.map_f]
rfl
· erw [Multiequalizer.lift_ι]
dsimp [Cover.index]
simp only [Functor.map_id, Category.comp_id]
rfl
#align category_theory.grothendieck_topology.plus_map_to_plus CategoryTheory.GrothendieckTopology.plusMap_toPlus
theorem isIso_toPlus_of_isSheaf (hP : Presheaf.IsSheaf J P) : IsIso (J.toPlus P) := by
rw [Presheaf.isSheaf_iff_multiequalizer] at hP
suffices ∀ X, IsIso ((J.toPlus P).app X) from NatIso.isIso_of_isIso_app _
intro X
suffices IsIso (colimit.ι (J.diagram P X.unop) (op ⊤)) from IsIso.comp_isIso
suffices ∀ (S T : (J.Cover X.unop)ᵒᵖ) (f : S ⟶ T), IsIso ((J.diagram P X.unop).map f) from
isIso_ι_of_isInitial (initialOpOfTerminal isTerminalTop) _
intro S T e
have : S.unop.toMultiequalizer P ≫ (J.diagram P X.unop).map e = T.unop.toMultiequalizer P :=
Multiequalizer.hom_ext _ _ _ (fun II => by dsimp; simp)
have :
(J.diagram P X.unop).map e = inv (S.unop.toMultiequalizer P) ≫ T.unop.toMultiequalizer P := by
simp [← this]
rw [this]
infer_instance
#align category_theory.grothendieck_topology.is_iso_to_plus_of_is_sheaf CategoryTheory.GrothendieckTopology.isIso_toPlus_of_isSheaf
def isoToPlus (hP : Presheaf.IsSheaf J P) : P ≅ J.plusObj P :=
letI := isIso_toPlus_of_isSheaf J P hP
asIso (J.toPlus P)
#align category_theory.grothendieck_topology.iso_to_plus CategoryTheory.GrothendieckTopology.isoToPlus
@[simp]
theorem isoToPlus_hom (hP : Presheaf.IsSheaf J P) : (J.isoToPlus P hP).hom = J.toPlus P :=
rfl
#align category_theory.grothendieck_topology.iso_to_plus_hom CategoryTheory.GrothendieckTopology.isoToPlus_hom
def plusLift {P Q : Cᵒᵖ ⥤ D} (η : P ⟶ Q) (hQ : Presheaf.IsSheaf J Q) : J.plusObj P ⟶ Q :=
J.plusMap η ≫ (J.isoToPlus Q hQ).inv
#align category_theory.grothendieck_topology.plus_lift CategoryTheory.GrothendieckTopology.plusLift
@[reassoc (attr := simp)]
theorem toPlus_plusLift {P Q : Cᵒᵖ ⥤ D} (η : P ⟶ Q) (hQ : Presheaf.IsSheaf J Q) :
J.toPlus P ≫ J.plusLift η hQ = η := by
dsimp [plusLift]
rw [← Category.assoc]
rw [Iso.comp_inv_eq]
dsimp only [isoToPlus, asIso]
rw [toPlus_naturality]
#align category_theory.grothendieck_topology.to_plus_plus_lift CategoryTheory.GrothendieckTopology.toPlus_plusLift
theorem plusLift_unique {P Q : Cᵒᵖ ⥤ D} (η : P ⟶ Q) (hQ : Presheaf.IsSheaf J Q)
(γ : J.plusObj P ⟶ Q) (hγ : J.toPlus P ≫ γ = η) : γ = J.plusLift η hQ := by
dsimp only [plusLift]
rw [Iso.eq_comp_inv, ← hγ, plusMap_comp]
simp
#align category_theory.grothendieck_topology.plus_lift_unique CategoryTheory.GrothendieckTopology.plusLift_unique
theorem plus_hom_ext {P Q : Cᵒᵖ ⥤ D} (η γ : J.plusObj P ⟶ Q) (hQ : Presheaf.IsSheaf J Q)
(h : J.toPlus P ≫ η = J.toPlus P ≫ γ) : η = γ := by
have : γ = J.plusLift (J.toPlus P ≫ γ) hQ := by
apply plusLift_unique
rfl
rw [this]
apply plusLift_unique
exact h
#align category_theory.grothendieck_topology.plus_hom_ext CategoryTheory.GrothendieckTopology.plus_hom_ext
@[simp]
theorem isoToPlus_inv (hP : Presheaf.IsSheaf J P) :
(J.isoToPlus P hP).inv = J.plusLift (𝟙 _) hP := by
apply J.plusLift_unique
rw [Iso.comp_inv_eq, Category.id_comp]
rfl
#align category_theory.grothendieck_topology.iso_to_plus_inv CategoryTheory.GrothendieckTopology.isoToPlus_inv
@[simp]
| Mathlib/CategoryTheory/Sites/Plus.lean | 342 | 345 | theorem plusMap_plusLift {P Q R : Cᵒᵖ ⥤ D} (η : P ⟶ Q) (γ : Q ⟶ R) (hR : Presheaf.IsSheaf J R) :
J.plusMap η ≫ J.plusLift γ hR = J.plusLift (η ≫ γ) hR := by |
apply J.plusLift_unique
rw [← Category.assoc, ← J.toPlus_naturality, Category.assoc, J.toPlus_plusLift]
|
import Mathlib.LinearAlgebra.AffineSpace.Basis
import Mathlib.LinearAlgebra.Matrix.NonsingularInverse
#align_import linear_algebra.affine_space.matrix from "leanprover-community/mathlib"@"2de9c37fa71dde2f1c6feff19876dd6a7b1519f0"
open Affine Matrix
open Set
universe u₁ u₂ u₃ u₄
variable {ι : Type u₁} {k : Type u₂} {V : Type u₃} {P : Type u₄}
variable [AddCommGroup V] [AffineSpace V P]
namespace AffineBasis
section Ring
variable [Ring k] [Module k V] (b : AffineBasis ι k P)
noncomputable def toMatrix {ι' : Type*} (q : ι' → P) : Matrix ι' ι k :=
fun i j => b.coord j (q i)
#align affine_basis.to_matrix AffineBasis.toMatrix
@[simp]
theorem toMatrix_apply {ι' : Type*} (q : ι' → P) (i : ι') (j : ι) :
b.toMatrix q i j = b.coord j (q i) := rfl
#align affine_basis.to_matrix_apply AffineBasis.toMatrix_apply
@[simp]
theorem toMatrix_self [DecidableEq ι] : b.toMatrix b = (1 : Matrix ι ι k) := by
ext i j
rw [toMatrix_apply, coord_apply, Matrix.one_eq_pi_single, Pi.single_apply]
#align affine_basis.to_matrix_self AffineBasis.toMatrix_self
variable {ι' : Type*}
theorem toMatrix_row_sum_one [Fintype ι] (q : ι' → P) (i : ι') : ∑ j, b.toMatrix q i j = 1 := by
simp
#align affine_basis.to_matrix_row_sum_one AffineBasis.toMatrix_row_sum_one
theorem affineIndependent_of_toMatrix_right_inv [Fintype ι] [Finite ι'] [DecidableEq ι']
(p : ι' → P) {A : Matrix ι ι' k} (hA : b.toMatrix p * A = 1) : AffineIndependent k p := by
cases nonempty_fintype ι'
rw [affineIndependent_iff_eq_of_fintype_affineCombination_eq]
intro w₁ w₂ hw₁ hw₂ hweq
have hweq' : w₁ ᵥ* b.toMatrix p = w₂ ᵥ* b.toMatrix p := by
ext j
change (∑ i, w₁ i • b.coord j (p i)) = ∑ i, w₂ i • b.coord j (p i)
-- Porting note: Added `u` because `∘` was causing trouble
have u : (fun i => b.coord j (p i)) = b.coord j ∘ p := by simp only [(· ∘ ·)]
rw [← Finset.univ.affineCombination_eq_linear_combination _ _ hw₁,
← Finset.univ.affineCombination_eq_linear_combination _ _ hw₂, u,
← Finset.univ.map_affineCombination p w₁ hw₁, ← Finset.univ.map_affineCombination p w₂ hw₂,
hweq]
replace hweq' := congr_arg (fun w => w ᵥ* A) hweq'
simpa only [Matrix.vecMul_vecMul, hA, Matrix.vecMul_one] using hweq'
#align affine_basis.affine_independent_of_to_matrix_right_inv AffineBasis.affineIndependent_of_toMatrix_right_inv
theorem affineSpan_eq_top_of_toMatrix_left_inv [Finite ι] [Fintype ι'] [DecidableEq ι]
[Nontrivial k] (p : ι' → P) {A : Matrix ι ι' k} (hA : A * b.toMatrix p = 1) :
affineSpan k (range p) = ⊤ := by
cases nonempty_fintype ι
suffices ∀ i, b i ∈ affineSpan k (range p) by
rw [eq_top_iff, ← b.tot, affineSpan_le]
rintro q ⟨i, rfl⟩
exact this i
intro i
have hAi : ∑ j, A i j = 1 := by
calc
∑ j, A i j = ∑ j, A i j * ∑ l, b.toMatrix p j l := by simp
_ = ∑ j, ∑ l, A i j * b.toMatrix p j l := by simp_rw [Finset.mul_sum]
_ = ∑ l, ∑ j, A i j * b.toMatrix p j l := by rw [Finset.sum_comm]
_ = ∑ l, (A * b.toMatrix p) i l := rfl
_ = 1 := by simp [hA, Matrix.one_apply, Finset.filter_eq]
have hbi : b i = Finset.univ.affineCombination k p (A i) := by
apply b.ext_elem
intro j
rw [b.coord_apply, Finset.univ.map_affineCombination _ _ hAi,
Finset.univ.affineCombination_eq_linear_combination _ _ hAi]
change _ = (A * b.toMatrix p) i j
simp_rw [hA, Matrix.one_apply, @eq_comm _ i j]
rw [hbi]
exact affineCombination_mem_affineSpan hAi p
#align affine_basis.affine_span_eq_top_of_to_matrix_left_inv AffineBasis.affineSpan_eq_top_of_toMatrix_left_inv
variable [Fintype ι] (b₂ : AffineBasis ι k P)
@[simp]
| Mathlib/LinearAlgebra/AffineSpace/Matrix.lean | 114 | 119 | theorem toMatrix_vecMul_coords (x : P) : b₂.coords x ᵥ* b.toMatrix b₂ = b.coords x := by |
ext j
change _ = b.coord j x
conv_rhs => rw [← b₂.affineCombination_coord_eq_self x]
rw [Finset.map_affineCombination _ _ _ (b₂.sum_coord_apply_eq_one x)]
simp [Matrix.vecMul, Matrix.dotProduct, toMatrix_apply, coords]
|
import Mathlib.LinearAlgebra.Quotient
import Mathlib.LinearAlgebra.Prod
#align_import linear_algebra.projection from "leanprover-community/mathlib"@"6d584f1709bedbed9175bd9350df46599bdd7213"
noncomputable section Ring
variable {R : Type*} [Ring R] {E : Type*} [AddCommGroup E] [Module R E]
variable {F : Type*} [AddCommGroup F] [Module R F] {G : Type*} [AddCommGroup G] [Module R G]
variable (p q : Submodule R E)
variable {S : Type*} [Semiring S] {M : Type*} [AddCommMonoid M] [Module S M] (m : Submodule S M)
namespace LinearMap
open Submodule
def ofIsCompl {p q : Submodule R E} (h : IsCompl p q) (φ : p →ₗ[R] F) (ψ : q →ₗ[R] F) : E →ₗ[R] F :=
LinearMap.coprod φ ψ ∘ₗ ↑(Submodule.prodEquivOfIsCompl _ _ h).symm
#align linear_map.of_is_compl LinearMap.ofIsCompl
variable {p q}
@[simp]
theorem ofIsCompl_left_apply (h : IsCompl p q) {φ : p →ₗ[R] F} {ψ : q →ₗ[R] F} (u : p) :
ofIsCompl h φ ψ (u : E) = φ u := by simp [ofIsCompl]
#align linear_map.of_is_compl_left_apply LinearMap.ofIsCompl_left_apply
@[simp]
theorem ofIsCompl_right_apply (h : IsCompl p q) {φ : p →ₗ[R] F} {ψ : q →ₗ[R] F} (v : q) :
ofIsCompl h φ ψ (v : E) = ψ v := by simp [ofIsCompl]
#align linear_map.of_is_compl_right_apply LinearMap.ofIsCompl_right_apply
theorem ofIsCompl_eq (h : IsCompl p q) {φ : p →ₗ[R] F} {ψ : q →ₗ[R] F} {χ : E →ₗ[R] F}
(hφ : ∀ u, φ u = χ u) (hψ : ∀ u, ψ u = χ u) : ofIsCompl h φ ψ = χ := by
ext x
obtain ⟨_, _, rfl, _⟩ := existsUnique_add_of_isCompl h x
simp [ofIsCompl, hφ, hψ]
#align linear_map.of_is_compl_eq LinearMap.ofIsCompl_eq
theorem ofIsCompl_eq' (h : IsCompl p q) {φ : p →ₗ[R] F} {ψ : q →ₗ[R] F} {χ : E →ₗ[R] F}
(hφ : φ = χ.comp p.subtype) (hψ : ψ = χ.comp q.subtype) : ofIsCompl h φ ψ = χ :=
ofIsCompl_eq h (fun _ => hφ.symm ▸ rfl) fun _ => hψ.symm ▸ rfl
#align linear_map.of_is_compl_eq' LinearMap.ofIsCompl_eq'
@[simp]
theorem ofIsCompl_zero (h : IsCompl p q) : (ofIsCompl h 0 0 : E →ₗ[R] F) = 0 :=
ofIsCompl_eq _ (fun _ => rfl) fun _ => rfl
#align linear_map.of_is_compl_zero LinearMap.ofIsCompl_zero
@[simp]
theorem ofIsCompl_add (h : IsCompl p q) {φ₁ φ₂ : p →ₗ[R] F} {ψ₁ ψ₂ : q →ₗ[R] F} :
ofIsCompl h (φ₁ + φ₂) (ψ₁ + ψ₂) = ofIsCompl h φ₁ ψ₁ + ofIsCompl h φ₂ ψ₂ :=
ofIsCompl_eq _ (by simp) (by simp)
#align linear_map.of_is_compl_add LinearMap.ofIsCompl_add
@[simp]
theorem ofIsCompl_smul {R : Type*} [CommRing R] {E : Type*} [AddCommGroup E] [Module R E]
{F : Type*} [AddCommGroup F] [Module R F] {p q : Submodule R E} (h : IsCompl p q)
{φ : p →ₗ[R] F} {ψ : q →ₗ[R] F} (c : R) : ofIsCompl h (c • φ) (c • ψ) = c • ofIsCompl h φ ψ :=
ofIsCompl_eq _ (by simp) (by simp)
#align linear_map.of_is_compl_smul LinearMap.ofIsCompl_smul
section
variable {R₁ : Type*} [CommRing R₁] [Module R₁ E] [Module R₁ F]
def ofIsComplProd {p q : Submodule R₁ E} (h : IsCompl p q) :
(p →ₗ[R₁] F) × (q →ₗ[R₁] F) →ₗ[R₁] E →ₗ[R₁] F where
toFun φ := ofIsCompl h φ.1 φ.2
map_add' := by intro φ ψ; dsimp only; rw [Prod.snd_add, Prod.fst_add, ofIsCompl_add]
map_smul' := by intro c φ; simp [Prod.smul_snd, Prod.smul_fst, ofIsCompl_smul]
#align linear_map.of_is_compl_prod LinearMap.ofIsComplProd
@[simp]
theorem ofIsComplProd_apply {p q : Submodule R₁ E} (h : IsCompl p q)
(φ : (p →ₗ[R₁] F) × (q →ₗ[R₁] F)) : ofIsComplProd h φ = ofIsCompl h φ.1 φ.2 :=
rfl
#align linear_map.of_is_compl_prod_apply LinearMap.ofIsComplProd_apply
def ofIsComplProdEquiv {p q : Submodule R₁ E} (h : IsCompl p q) :
((p →ₗ[R₁] F) × (q →ₗ[R₁] F)) ≃ₗ[R₁] E →ₗ[R₁] F :=
{ ofIsComplProd h with
invFun := fun φ => ⟨φ.domRestrict p, φ.domRestrict q⟩
left_inv := fun φ ↦ by
ext x
· exact ofIsCompl_left_apply h x
· exact ofIsCompl_right_apply h x
right_inv := fun φ ↦ by
ext x
obtain ⟨a, b, hab, _⟩ := existsUnique_add_of_isCompl h x
rw [← hab]; simp }
#align linear_map.of_is_compl_prod_equiv LinearMap.ofIsComplProdEquiv
end
@[simp, nolint simpNF] -- Porting note: linter claims that LHS doesn't simplify, but it does
| Mathlib/LinearAlgebra/Projection.lean | 308 | 313 | theorem linearProjOfIsCompl_of_proj (f : E →ₗ[R] p) (hf : ∀ x : p, f x = x) :
p.linearProjOfIsCompl (ker f) (isCompl_of_proj hf) = f := by |
ext x
have : x ∈ p ⊔ (ker f) := by simp only [(isCompl_of_proj hf).sup_eq_top, mem_top]
rcases mem_sup'.1 this with ⟨x, y, rfl⟩
simp [hf]
|
import Aesop
import Mathlib.Algebra.Group.Defs
import Mathlib.Data.Nat.Defs
import Mathlib.Data.Int.Defs
import Mathlib.Logic.Function.Basic
import Mathlib.Tactic.Cases
import Mathlib.Tactic.SimpRw
import Mathlib.Tactic.SplitIfs
#align_import algebra.group.basic from "leanprover-community/mathlib"@"a07d750983b94c530ab69a726862c2ab6802b38c"
assert_not_exists MonoidWithZero
assert_not_exists DenselyOrdered
open Function
universe u
variable {α β G M : Type*}
@[to_additive]
instance CommMagma.to_isCommutative [CommMagma G] : Std.Commutative (α := G) (· * ·) := ⟨mul_comm⟩
#align comm_semigroup.to_is_commutative CommMagma.to_isCommutative
#align add_comm_semigroup.to_is_commutative AddCommMagma.to_isCommutative
attribute [local simp] mul_assoc sub_eq_add_neg
section Group
variable [Group G] {a b c d : G} {n : ℤ}
@[to_additive (attr := simp)]
theorem div_eq_inv_self : a / b = b⁻¹ ↔ a = 1 := by rw [div_eq_mul_inv, mul_left_eq_self]
#align div_eq_inv_self div_eq_inv_self
#align sub_eq_neg_self sub_eq_neg_self
@[to_additive]
theorem mul_left_surjective (a : G) : Surjective (a * ·) :=
fun x ↦ ⟨a⁻¹ * x, mul_inv_cancel_left a x⟩
#align mul_left_surjective mul_left_surjective
#align add_left_surjective add_left_surjective
@[to_additive]
theorem mul_right_surjective (a : G) : Function.Surjective fun x ↦ x * a := fun x ↦
⟨x * a⁻¹, inv_mul_cancel_right x a⟩
#align mul_right_surjective mul_right_surjective
#align add_right_surjective add_right_surjective
@[to_additive]
theorem eq_mul_inv_of_mul_eq (h : a * c = b) : a = b * c⁻¹ := by simp [h.symm]
#align eq_mul_inv_of_mul_eq eq_mul_inv_of_mul_eq
#align eq_add_neg_of_add_eq eq_add_neg_of_add_eq
@[to_additive]
theorem eq_inv_mul_of_mul_eq (h : b * a = c) : a = b⁻¹ * c := by simp [h.symm]
#align eq_inv_mul_of_mul_eq eq_inv_mul_of_mul_eq
#align eq_neg_add_of_add_eq eq_neg_add_of_add_eq
@[to_additive]
| Mathlib/Algebra/Group/Basic.lean | 890 | 890 | theorem inv_mul_eq_of_eq_mul (h : b = a * c) : a⁻¹ * b = c := by | simp [h]
|
import Mathlib.SetTheory.Cardinal.Finite
#align_import data.set.ncard from "leanprover-community/mathlib"@"74c2af38a828107941029b03839882c5c6f87a04"
namespace Set
variable {α β : Type*} {s t : Set α}
noncomputable def encard (s : Set α) : ℕ∞ := PartENat.withTopEquiv (PartENat.card s)
@[simp] theorem encard_univ_coe (s : Set α) : encard (univ : Set s) = encard s := by
rw [encard, encard, PartENat.card_congr (Equiv.Set.univ ↑s)]
theorem encard_univ (α : Type*) :
encard (univ : Set α) = PartENat.withTopEquiv (PartENat.card α) := by
rw [encard, PartENat.card_congr (Equiv.Set.univ α)]
theorem Finite.encard_eq_coe_toFinset_card (h : s.Finite) : s.encard = h.toFinset.card := by
have := h.fintype
rw [encard, PartENat.card_eq_coe_fintype_card,
PartENat.withTopEquiv_natCast, toFinite_toFinset, toFinset_card]
theorem encard_eq_coe_toFinset_card (s : Set α) [Fintype s] : encard s = s.toFinset.card := by
have h := toFinite s
rw [h.encard_eq_coe_toFinset_card, toFinite_toFinset]
theorem encard_coe_eq_coe_finsetCard (s : Finset α) : encard (s : Set α) = s.card := by
rw [Finite.encard_eq_coe_toFinset_card (Finset.finite_toSet s)]; simp
theorem Infinite.encard_eq {s : Set α} (h : s.Infinite) : s.encard = ⊤ := by
have := h.to_subtype
rw [encard, ← PartENat.withTopEquiv.symm.injective.eq_iff, Equiv.symm_apply_apply,
PartENat.withTopEquiv_symm_top, PartENat.card_eq_top_of_infinite]
@[simp] theorem encard_eq_zero : s.encard = 0 ↔ s = ∅ := by
rw [encard, ← PartENat.withTopEquiv.symm.injective.eq_iff, Equiv.symm_apply_apply,
PartENat.withTopEquiv_symm_zero, PartENat.card_eq_zero_iff_empty, isEmpty_subtype,
eq_empty_iff_forall_not_mem]
@[simp] theorem encard_empty : (∅ : Set α).encard = 0 := by
rw [encard_eq_zero]
theorem nonempty_of_encard_ne_zero (h : s.encard ≠ 0) : s.Nonempty := by
rwa [nonempty_iff_ne_empty, Ne, ← encard_eq_zero]
theorem encard_ne_zero : s.encard ≠ 0 ↔ s.Nonempty := by
rw [ne_eq, encard_eq_zero, nonempty_iff_ne_empty]
@[simp] theorem encard_pos : 0 < s.encard ↔ s.Nonempty := by
rw [pos_iff_ne_zero, encard_ne_zero]
@[simp] theorem encard_singleton (e : α) : ({e} : Set α).encard = 1 := by
rw [encard, ← PartENat.withTopEquiv.symm.injective.eq_iff, Equiv.symm_apply_apply,
PartENat.card_eq_coe_fintype_card, Fintype.card_ofSubsingleton, Nat.cast_one]; rfl
theorem encard_union_eq (h : Disjoint s t) : (s ∪ t).encard = s.encard + t.encard := by
classical
have e := (Equiv.Set.union (by rwa [subset_empty_iff, ← disjoint_iff_inter_eq_empty])).symm
simp [encard, ← PartENat.card_congr e, PartENat.card_sum, PartENat.withTopEquiv]
theorem encard_insert_of_not_mem {a : α} (has : a ∉ s) : (insert a s).encard = s.encard + 1 := by
rw [← union_singleton, encard_union_eq (by simpa), encard_singleton]
theorem Finite.encard_lt_top (h : s.Finite) : s.encard < ⊤ := by
refine h.induction_on (by simp) ?_
rintro a t hat _ ht'
rw [encard_insert_of_not_mem hat]
exact lt_tsub_iff_right.1 ht'
theorem Finite.encard_eq_coe (h : s.Finite) : s.encard = ENat.toNat s.encard :=
(ENat.coe_toNat h.encard_lt_top.ne).symm
theorem Finite.exists_encard_eq_coe (h : s.Finite) : ∃ (n : ℕ), s.encard = n :=
⟨_, h.encard_eq_coe⟩
@[simp] theorem encard_lt_top_iff : s.encard < ⊤ ↔ s.Finite :=
⟨fun h ↦ by_contra fun h' ↦ h.ne (Infinite.encard_eq h'), Finite.encard_lt_top⟩
@[simp] theorem encard_eq_top_iff : s.encard = ⊤ ↔ s.Infinite := by
rw [← not_iff_not, ← Ne, ← lt_top_iff_ne_top, encard_lt_top_iff, not_infinite]
theorem encard_ne_top_iff : s.encard ≠ ⊤ ↔ s.Finite := by
simp
theorem finite_of_encard_le_coe {k : ℕ} (h : s.encard ≤ k) : s.Finite := by
rw [← encard_lt_top_iff]; exact h.trans_lt (WithTop.coe_lt_top _)
theorem finite_of_encard_eq_coe {k : ℕ} (h : s.encard = k) : s.Finite :=
finite_of_encard_le_coe h.le
theorem encard_le_coe_iff {k : ℕ} : s.encard ≤ k ↔ s.Finite ∧ ∃ (n₀ : ℕ), s.encard = n₀ ∧ n₀ ≤ k :=
⟨fun h ↦ ⟨finite_of_encard_le_coe h, by rwa [ENat.le_coe_iff] at h⟩,
fun ⟨_,⟨n₀,hs, hle⟩⟩ ↦ by rwa [hs, Nat.cast_le]⟩
section InsertErase
variable {a b : α}
theorem encard_insert_le (s : Set α) (x : α) : (insert x s).encard ≤ s.encard + 1 := by
rw [← union_singleton, ← encard_singleton x]; apply encard_union_le
| Mathlib/Data/Set/Card.lean | 240 | 241 | theorem encard_singleton_inter (s : Set α) (x : α) : ({x} ∩ s).encard ≤ 1 := by |
rw [← encard_singleton x]; exact encard_le_card inter_subset_left
|
import Mathlib.Analysis.NormedSpace.Basic
import Mathlib.Analysis.Normed.Group.Hom
import Mathlib.Data.Real.Sqrt
import Mathlib.RingTheory.Ideal.QuotientOperations
import Mathlib.Topology.MetricSpace.HausdorffDistance
#align_import analysis.normed.group.quotient from "leanprover-community/mathlib"@"2196ab363eb097c008d4497125e0dde23fb36db2"
noncomputable section
open QuotientAddGroup Metric Set Topology NNReal
variable {M N : Type*} [SeminormedAddCommGroup M] [SeminormedAddCommGroup N]
noncomputable instance normOnQuotient (S : AddSubgroup M) : Norm (M ⧸ S) where
norm x := sInf (norm '' { m | mk' S m = x })
#align norm_on_quotient normOnQuotient
theorem AddSubgroup.quotient_norm_eq {S : AddSubgroup M} (x : M ⧸ S) :
‖x‖ = sInf (norm '' { m : M | (m : M ⧸ S) = x }) :=
rfl
#align add_subgroup.quotient_norm_eq AddSubgroup.quotient_norm_eq
theorem QuotientAddGroup.norm_eq_infDist {S : AddSubgroup M} (x : M ⧸ S) :
‖x‖ = infDist 0 { m : M | (m : M ⧸ S) = x } := by
simp only [AddSubgroup.quotient_norm_eq, infDist_eq_iInf, sInf_image', dist_zero_left]
theorem QuotientAddGroup.norm_mk {S : AddSubgroup M} (x : M) :
‖(x : M ⧸ S)‖ = infDist x S := by
rw [norm_eq_infDist, ← infDist_image (IsometryEquiv.subLeft x).isometry,
IsometryEquiv.subLeft_apply, sub_zero, ← IsometryEquiv.preimage_symm]
congr 1 with y
simp only [mem_preimage, IsometryEquiv.subLeft_symm_apply, mem_setOf_eq, QuotientAddGroup.eq,
neg_add, neg_neg, neg_add_cancel_right, SetLike.mem_coe]
theorem image_norm_nonempty {S : AddSubgroup M} (x : M ⧸ S) :
(norm '' { m | mk' S m = x }).Nonempty :=
.image _ <| Quot.exists_rep x
#align image_norm_nonempty image_norm_nonempty
theorem bddBelow_image_norm (s : Set M) : BddBelow (norm '' s) :=
⟨0, forall_mem_image.2 fun _ _ ↦ norm_nonneg _⟩
#align bdd_below_image_norm bddBelow_image_norm
theorem isGLB_quotient_norm {S : AddSubgroup M} (x : M ⧸ S) :
IsGLB (norm '' { m | mk' S m = x }) (‖x‖) :=
isGLB_csInf (image_norm_nonempty x) (bddBelow_image_norm _)
theorem quotient_norm_neg {S : AddSubgroup M} (x : M ⧸ S) : ‖-x‖ = ‖x‖ := by
simp only [AddSubgroup.quotient_norm_eq]
congr 1 with r
constructor <;> { rintro ⟨m, hm, rfl⟩; use -m; simpa [neg_eq_iff_eq_neg] using hm }
#align quotient_norm_neg quotient_norm_neg
theorem quotient_norm_sub_rev {S : AddSubgroup M} (x y : M ⧸ S) : ‖x - y‖ = ‖y - x‖ := by
rw [← neg_sub, quotient_norm_neg]
#align quotient_norm_sub_rev quotient_norm_sub_rev
theorem quotient_norm_mk_le (S : AddSubgroup M) (m : M) : ‖mk' S m‖ ≤ ‖m‖ :=
csInf_le (bddBelow_image_norm _) <| Set.mem_image_of_mem _ rfl
#align quotient_norm_mk_le quotient_norm_mk_le
theorem quotient_norm_mk_le' (S : AddSubgroup M) (m : M) : ‖(m : M ⧸ S)‖ ≤ ‖m‖ :=
quotient_norm_mk_le S m
#align quotient_norm_mk_le' quotient_norm_mk_le'
theorem quotient_norm_mk_eq (S : AddSubgroup M) (m : M) :
‖mk' S m‖ = sInf ((‖m + ·‖) '' S) := by
rw [mk'_apply, norm_mk, sInf_image', ← infDist_image isometry_neg, image_neg,
neg_coe_set (H := S), infDist_eq_iInf]
simp only [dist_eq_norm', sub_neg_eq_add, add_comm]
#align quotient_norm_mk_eq quotient_norm_mk_eq
theorem quotient_norm_nonneg (S : AddSubgroup M) (x : M ⧸ S) : 0 ≤ ‖x‖ :=
Real.sInf_nonneg _ <| forall_mem_image.2 fun _ _ ↦ norm_nonneg _
#align quotient_norm_nonneg quotient_norm_nonneg
theorem norm_mk_nonneg (S : AddSubgroup M) (m : M) : 0 ≤ ‖mk' S m‖ :=
quotient_norm_nonneg S _
#align norm_mk_nonneg norm_mk_nonneg
theorem quotient_norm_eq_zero_iff (S : AddSubgroup M) (m : M) :
‖mk' S m‖ = 0 ↔ m ∈ closure (S : Set M) := by
rw [mk'_apply, norm_mk, ← mem_closure_iff_infDist_zero]
exact ⟨0, S.zero_mem⟩
#align quotient_norm_eq_zero_iff quotient_norm_eq_zero_iff
theorem QuotientAddGroup.norm_lt_iff {S : AddSubgroup M} {x : M ⧸ S} {r : ℝ} :
‖x‖ < r ↔ ∃ m : M, ↑m = x ∧ ‖m‖ < r := by
rw [isGLB_lt_iff (isGLB_quotient_norm _), exists_mem_image]
rfl
theorem norm_mk_lt {S : AddSubgroup M} (x : M ⧸ S) {ε : ℝ} (hε : 0 < ε) :
∃ m : M, mk' S m = x ∧ ‖m‖ < ‖x‖ + ε :=
norm_lt_iff.1 <| lt_add_of_pos_right _ hε
#align norm_mk_lt norm_mk_lt
theorem norm_mk_lt' (S : AddSubgroup M) (m : M) {ε : ℝ} (hε : 0 < ε) :
∃ s ∈ S, ‖m + s‖ < ‖mk' S m‖ + ε := by
obtain ⟨n : M, hn : mk' S n = mk' S m, hn' : ‖n‖ < ‖mk' S m‖ + ε⟩ :=
norm_mk_lt (QuotientAddGroup.mk' S m) hε
erw [eq_comm, QuotientAddGroup.eq] at hn
use -m + n, hn
rwa [add_neg_cancel_left]
#align norm_mk_lt' norm_mk_lt'
set_option backward.synthInstance.canonInstances false in -- See https://github.com/leanprover-community/mathlib4/issues/12532
theorem quotient_norm_add_le (S : AddSubgroup M) (x y : M ⧸ S) : ‖x + y‖ ≤ ‖x‖ + ‖y‖ := by
rcases And.intro (mk_surjective x) (mk_surjective y) with ⟨⟨x, rfl⟩, ⟨y, rfl⟩⟩
simp only [← mk'_apply, ← map_add, quotient_norm_mk_eq, sInf_image']
refine le_ciInf_add_ciInf fun a b ↦ ?_
refine ciInf_le_of_le ⟨0, forall_mem_range.2 fun _ ↦ norm_nonneg _⟩ (a + b) ?_
exact (congr_arg norm (add_add_add_comm _ _ _ _)).trans_le (norm_add_le _ _)
#align quotient_norm_add_le quotient_norm_add_le
theorem norm_mk_zero (S : AddSubgroup M) : ‖(0 : M ⧸ S)‖ = 0 := by
erw [quotient_norm_eq_zero_iff]
exact subset_closure S.zero_mem
#align norm_mk_zero norm_mk_zero
theorem norm_mk_eq_zero (S : AddSubgroup M) (hS : IsClosed (S : Set M)) (m : M)
(h : ‖mk' S m‖ = 0) : m ∈ S := by rwa [quotient_norm_eq_zero_iff, hS.closure_eq] at h
#align norm_zero_eq_zero norm_mk_eq_zero
| Mathlib/Analysis/Normed/Group/Quotient.lean | 231 | 238 | theorem quotient_nhd_basis (S : AddSubgroup M) :
(𝓝 (0 : M ⧸ S)).HasBasis (fun ε ↦ 0 < ε) fun ε ↦ { x | ‖x‖ < ε } := by |
have : ∀ ε : ℝ, mk '' ball (0 : M) ε = { x : M ⧸ S | ‖x‖ < ε } := by
refine fun ε ↦ Set.ext <| forall_mk.2 fun x ↦ ?_
rw [ball_zero_eq, mem_setOf_eq, norm_lt_iff, mem_image]
exact exists_congr fun _ ↦ and_comm
rw [← mk_zero, nhds_eq, ← funext this]
exact .map _ Metric.nhds_basis_ball
|
import Mathlib.Data.SetLike.Fintype
import Mathlib.Algebra.Divisibility.Prod
import Mathlib.RingTheory.Nakayama
import Mathlib.RingTheory.SimpleModule
import Mathlib.Tactic.RSuffices
#align_import ring_theory.artinian from "leanprover-community/mathlib"@"210657c4ea4a4a7b234392f70a3a2a83346dfa90"
open Set Filter Pointwise
class IsArtinian (R M) [Semiring R] [AddCommMonoid M] [Module R M] : Prop where
wellFounded_submodule_lt' : WellFounded ((· < ·) : Submodule R M → Submodule R M → Prop)
#align is_artinian IsArtinian
section
variable {R M P N : Type*}
variable [Ring R] [AddCommGroup M] [AddCommGroup P] [AddCommGroup N]
variable [Module R M] [Module R P] [Module R N]
open IsArtinian
theorem IsArtinian.wellFounded_submodule_lt (R M) [Semiring R] [AddCommMonoid M] [Module R M]
[IsArtinian R M] : WellFounded ((· < ·) : Submodule R M → Submodule R M → Prop) :=
IsArtinian.wellFounded_submodule_lt'
#align is_artinian.well_founded_submodule_lt IsArtinian.wellFounded_submodule_lt
theorem isArtinian_of_injective (f : M →ₗ[R] P) (h : Function.Injective f) [IsArtinian R P] :
IsArtinian R M :=
⟨Subrelation.wf
(fun {A B} hAB => show A.map f < B.map f from Submodule.map_strictMono_of_injective h hAB)
(InvImage.wf (Submodule.map f) (IsArtinian.wellFounded_submodule_lt R P))⟩
#align is_artinian_of_injective isArtinian_of_injective
instance isArtinian_submodule' [IsArtinian R M] (N : Submodule R M) : IsArtinian R N :=
isArtinian_of_injective N.subtype Subtype.val_injective
#align is_artinian_submodule' isArtinian_submodule'
theorem isArtinian_of_le {s t : Submodule R M} [IsArtinian R t] (h : s ≤ t) : IsArtinian R s :=
isArtinian_of_injective (Submodule.inclusion h) (Submodule.inclusion_injective h)
#align is_artinian_of_le isArtinian_of_le
variable (M)
theorem isArtinian_of_surjective (f : M →ₗ[R] P) (hf : Function.Surjective f) [IsArtinian R M] :
IsArtinian R P :=
⟨Subrelation.wf
(fun {A B} hAB =>
show A.comap f < B.comap f from Submodule.comap_strictMono_of_surjective hf hAB)
(InvImage.wf (Submodule.comap f) (IsArtinian.wellFounded_submodule_lt R M))⟩
#align is_artinian_of_surjective isArtinian_of_surjective
variable {M}
theorem isArtinian_of_linearEquiv (f : M ≃ₗ[R] P) [IsArtinian R M] : IsArtinian R P :=
isArtinian_of_surjective _ f.toLinearMap f.toEquiv.surjective
#align is_artinian_of_linear_equiv isArtinian_of_linearEquiv
theorem isArtinian_of_range_eq_ker [IsArtinian R M] [IsArtinian R P] (f : M →ₗ[R] N) (g : N →ₗ[R] P)
(hf : Function.Injective f) (hg : Function.Surjective g)
(h : LinearMap.range f = LinearMap.ker g) : IsArtinian R N :=
⟨wellFounded_lt_exact_sequence (IsArtinian.wellFounded_submodule_lt R M)
(IsArtinian.wellFounded_submodule_lt R P) (LinearMap.range f) (Submodule.map f)
(Submodule.comap f) (Submodule.comap g) (Submodule.map g) (Submodule.gciMapComap hf)
(Submodule.giMapComap hg)
(by simp [Submodule.map_comap_eq, inf_comm]) (by simp [Submodule.comap_map_eq, h])⟩
#align is_artinian_of_range_eq_ker isArtinian_of_range_eq_ker
instance isArtinian_prod [IsArtinian R M] [IsArtinian R P] : IsArtinian R (M × P) :=
isArtinian_of_range_eq_ker (LinearMap.inl R M P) (LinearMap.snd R M P) LinearMap.inl_injective
LinearMap.snd_surjective (LinearMap.range_inl R M P)
#align is_artinian_prod isArtinian_prod
instance (priority := 100) isArtinian_of_finite [Finite M] : IsArtinian R M :=
⟨Finite.wellFounded_of_trans_of_irrefl _⟩
#align is_artinian_of_finite isArtinian_of_finite
-- Porting note: elab_as_elim can only be global and cannot be changed on an imported decl
-- attribute [local elab_as_elim] Finite.induction_empty_option
instance isArtinian_pi {R ι : Type*} [Finite ι] :
∀ {M : ι → Type*} [Ring R] [∀ i, AddCommGroup (M i)],
∀ [∀ i, Module R (M i)], ∀ [∀ i, IsArtinian R (M i)], IsArtinian R (∀ i, M i) := by
apply Finite.induction_empty_option _ _ _ ι
· intro α β e hα M _ _ _ _
have := @hα
exact isArtinian_of_linearEquiv (LinearEquiv.piCongrLeft R M e)
· intro M _ _ _ _
infer_instance
· intro α _ ih M _ _ _ _
have := @ih
exact isArtinian_of_linearEquiv (LinearEquiv.piOptionEquivProd R).symm
#align is_artinian_pi isArtinian_pi
instance isArtinian_pi' {R ι M : Type*} [Ring R] [AddCommGroup M] [Module R M] [Finite ι]
[IsArtinian R M] : IsArtinian R (ι → M) :=
isArtinian_pi
#align is_artinian_pi' isArtinian_pi'
--porting note (#10754): new instance
instance isArtinian_finsupp {R ι M : Type*} [Ring R] [AddCommGroup M] [Module R M] [Finite ι]
[IsArtinian R M] : IsArtinian R (ι →₀ M) :=
isArtinian_of_linearEquiv (Finsupp.linearEquivFunOnFinite _ _ _).symm
end
open IsArtinian Submodule Function
section Ring
variable {R M : Type*} [Ring R] [AddCommGroup M] [Module R M]
theorem isArtinian_iff_wellFounded :
IsArtinian R M ↔ WellFounded ((· < ·) : Submodule R M → Submodule R M → Prop) :=
⟨fun h => h.1, IsArtinian.mk⟩
#align is_artinian_iff_well_founded isArtinian_iff_wellFounded
theorem IsArtinian.finite_of_linearIndependent [Nontrivial R] [IsArtinian R M] {s : Set M}
(hs : LinearIndependent R ((↑) : s → M)) : s.Finite := by
refine by_contradiction fun hf => (RelEmbedding.wellFounded_iff_no_descending_seq.1
(wellFounded_submodule_lt (R := R) (M := M))).elim' ?_
have f : ℕ ↪ s := Set.Infinite.natEmbedding s hf
have : ∀ n, (↑) ∘ f '' { m | n ≤ m } ⊆ s := by
rintro n x ⟨y, _, rfl⟩
exact (f y).2
have : ∀ a b : ℕ, a ≤ b ↔
span R (Subtype.val ∘ f '' { m | b ≤ m }) ≤ span R (Subtype.val ∘ f '' { m | a ≤ m }) := by
intro a b
rw [span_le_span_iff hs (this b) (this a),
Set.image_subset_image_iff (Subtype.coe_injective.comp f.injective), Set.subset_def]
simp only [Set.mem_setOf_eq]
exact ⟨fun hab x => le_trans hab, fun h => h _ le_rfl⟩
exact ⟨⟨fun n => span R (Subtype.val ∘ f '' { m | n ≤ m }), fun x y => by
rw [le_antisymm_iff, ← this y x, ← this x y]
exact fun ⟨h₁, h₂⟩ => le_antisymm_iff.2 ⟨h₂, h₁⟩⟩, by
intro a b
conv_rhs => rw [GT.gt, lt_iff_le_not_le, this, this, ← lt_iff_le_not_le]
rfl⟩
#align is_artinian.finite_of_linear_independent IsArtinian.finite_of_linearIndependent
theorem set_has_minimal_iff_artinian :
(∀ a : Set <| Submodule R M, a.Nonempty → ∃ M' ∈ a, ∀ I ∈ a, ¬I < M') ↔ IsArtinian R M := by
rw [isArtinian_iff_wellFounded, WellFounded.wellFounded_iff_has_min]
#align set_has_minimal_iff_artinian set_has_minimal_iff_artinian
theorem IsArtinian.set_has_minimal [IsArtinian R M] (a : Set <| Submodule R M) (ha : a.Nonempty) :
∃ M' ∈ a, ∀ I ∈ a, ¬I < M' :=
set_has_minimal_iff_artinian.mpr ‹_› a ha
#align is_artinian.set_has_minimal IsArtinian.set_has_minimal
theorem monotone_stabilizes_iff_artinian :
(∀ f : ℕ →o (Submodule R M)ᵒᵈ, ∃ n, ∀ m, n ≤ m → f n = f m) ↔ IsArtinian R M := by
rw [isArtinian_iff_wellFounded]
exact WellFounded.monotone_chain_condition.symm
#align monotone_stabilizes_iff_artinian monotone_stabilizes_iff_artinian
namespace LinearMap
variable [IsArtinian R M]
theorem eventually_codisjoint_ker_pow_range_pow (f : M →ₗ[R] M) :
∀ᶠ n in atTop, Codisjoint (LinearMap.ker (f ^ n)) (LinearMap.range (f ^ n)) := by
obtain ⟨n, hn : ∀ m, n ≤ m → LinearMap.range (f ^ n) = LinearMap.range (f ^ m)⟩ :=
monotone_stabilizes f.iterateRange
refine eventually_atTop.mpr ⟨n, fun m hm ↦ codisjoint_iff.mpr ?_⟩
simp_rw [← hn _ hm, Submodule.eq_top_iff', Submodule.mem_sup]
intro x
rsuffices ⟨y, hy⟩ : ∃ y, (f ^ m) ((f ^ n) y) = (f ^ m) x
· exact ⟨x - (f ^ n) y, by simp [hy], (f ^ n) y, by simp⟩
-- Note: #8386 had to change `mem_range` into `mem_range (f := _)`
simp_rw [f.pow_apply n, f.pow_apply m, ← iterate_add_apply, ← f.pow_apply (m + n),
← f.pow_apply m, ← mem_range (f := _), ← hn _ (n.le_add_left m), hn _ hm]
exact LinearMap.mem_range_self (f ^ m) x
#align is_artinian.exists_endomorphism_iterate_ker_sup_range_eq_top LinearMap.eventually_codisjoint_ker_pow_range_pow
lemma eventually_iInf_range_pow_eq (f : Module.End R M) :
∀ᶠ n in atTop, ⨅ m, LinearMap.range (f ^ m) = LinearMap.range (f ^ n) := by
obtain ⟨n, hn : ∀ m, n ≤ m → LinearMap.range (f ^ n) = LinearMap.range (f ^ m)⟩ :=
monotone_stabilizes f.iterateRange
refine eventually_atTop.mpr ⟨n, fun l hl ↦ le_antisymm (iInf_le _ _) (le_iInf fun m ↦ ?_)⟩
rcases le_or_lt l m with h | h
· rw [← hn _ (hl.trans h), hn _ hl]
· exact f.iterateRange.monotone h.le
| Mathlib/RingTheory/Artinian.lean | 270 | 274 | theorem eventually_isCompl_ker_pow_range_pow [IsNoetherian R M] (f : M →ₗ[R] M) :
∀ᶠ n in atTop, IsCompl (LinearMap.ker (f ^ n)) (LinearMap.range (f ^ n)) := by |
filter_upwards [f.eventually_disjoint_ker_pow_range_pow.and
f.eventually_codisjoint_ker_pow_range_pow] with n hn
simpa only [isCompl_iff]
|
import Mathlib.Algebra.CharP.Defs
import Mathlib.RingTheory.Multiplicity
import Mathlib.RingTheory.PowerSeries.Basic
#align_import ring_theory.power_series.basic from "leanprover-community/mathlib"@"2d5739b61641ee4e7e53eca5688a08f66f2e6a60"
noncomputable section
open Polynomial
open Finset (antidiagonal mem_antidiagonal)
namespace PowerSeries
open Finsupp (single)
variable {R : Type*}
section OrderBasic
open multiplicity
variable [Semiring R] {φ : R⟦X⟧}
theorem exists_coeff_ne_zero_iff_ne_zero : (∃ n : ℕ, coeff R n φ ≠ 0) ↔ φ ≠ 0 := by
refine not_iff_not.mp ?_
push_neg
-- FIXME: the `FunLike.coe` doesn't seem to be picked up in the expression after #8386?
simp [PowerSeries.ext_iff, (coeff R _).map_zero]
#align power_series.exists_coeff_ne_zero_iff_ne_zero PowerSeries.exists_coeff_ne_zero_iff_ne_zero
def order (φ : R⟦X⟧) : PartENat :=
letI := Classical.decEq R
letI := Classical.decEq R⟦X⟧
if h : φ = 0 then ⊤ else Nat.find (exists_coeff_ne_zero_iff_ne_zero.mpr h)
#align power_series.order PowerSeries.order
@[simp]
theorem order_zero : order (0 : R⟦X⟧) = ⊤ :=
dif_pos rfl
#align power_series.order_zero PowerSeries.order_zero
theorem order_finite_iff_ne_zero : (order φ).Dom ↔ φ ≠ 0 := by
simp only [order]
constructor
· split_ifs with h <;> intro H
· simp only [PartENat.top_eq_none, Part.not_none_dom] at H
· exact h
· intro h
simp [h]
#align power_series.order_finite_iff_ne_zero PowerSeries.order_finite_iff_ne_zero
theorem coeff_order (h : (order φ).Dom) : coeff R (φ.order.get h) φ ≠ 0 := by
classical
simp only [order, order_finite_iff_ne_zero.mp h, not_false_iff, dif_neg, PartENat.get_natCast']
generalize_proofs h
exact Nat.find_spec h
#align power_series.coeff_order PowerSeries.coeff_order
theorem order_le (n : ℕ) (h : coeff R n φ ≠ 0) : order φ ≤ n := by
classical
rw [order, dif_neg]
· simp only [PartENat.coe_le_coe]
exact Nat.find_le h
· exact exists_coeff_ne_zero_iff_ne_zero.mp ⟨n, h⟩
#align power_series.order_le PowerSeries.order_le
theorem coeff_of_lt_order (n : ℕ) (h : ↑n < order φ) : coeff R n φ = 0 := by
contrapose! h
exact order_le _ h
#align power_series.coeff_of_lt_order PowerSeries.coeff_of_lt_order
@[simp]
theorem order_eq_top {φ : R⟦X⟧} : φ.order = ⊤ ↔ φ = 0 :=
PartENat.not_dom_iff_eq_top.symm.trans order_finite_iff_ne_zero.not_left
#align power_series.order_eq_top PowerSeries.order_eq_top
theorem nat_le_order (φ : R⟦X⟧) (n : ℕ) (h : ∀ i < n, coeff R i φ = 0) : ↑n ≤ order φ := by
by_contra H; rw [not_le] at H
have : (order φ).Dom := PartENat.dom_of_le_natCast H.le
rw [← PartENat.natCast_get this, PartENat.coe_lt_coe] at H
exact coeff_order this (h _ H)
#align power_series.nat_le_order PowerSeries.nat_le_order
theorem le_order (φ : R⟦X⟧) (n : PartENat) (h : ∀ i : ℕ, ↑i < n → coeff R i φ = 0) :
n ≤ order φ := by
induction n using PartENat.casesOn
· show _ ≤ _
rw [top_le_iff, order_eq_top]
ext i
exact h _ (PartENat.natCast_lt_top i)
· apply nat_le_order
simpa only [PartENat.coe_lt_coe] using h
#align power_series.le_order PowerSeries.le_order
| Mathlib/RingTheory/PowerSeries/Order.lean | 134 | 139 | theorem order_eq_nat {φ : R⟦X⟧} {n : ℕ} :
order φ = n ↔ coeff R n φ ≠ 0 ∧ ∀ i, i < n → coeff R i φ = 0 := by |
classical
rcases eq_or_ne φ 0 with (rfl | hφ)
· simpa [(coeff R _).map_zero] using (PartENat.natCast_ne_top _).symm
simp [order, dif_neg hφ, Nat.find_eq_iff]
|
import Mathlib.Algebra.Polynomial.Eval
import Mathlib.LinearAlgebra.Dimension.Constructions
#align_import algebra.linear_recurrence from "leanprover-community/mathlib"@"039a089d2a4b93c761b234f3e5f5aeb752bac60f"
noncomputable section
open Finset
open Polynomial
structure LinearRecurrence (α : Type*) [CommSemiring α] where
order : ℕ
coeffs : Fin order → α
#align linear_recurrence LinearRecurrence
instance (α : Type*) [CommSemiring α] : Inhabited (LinearRecurrence α) :=
⟨⟨0, default⟩⟩
namespace LinearRecurrence
section CommSemiring
variable {α : Type*} [CommSemiring α] (E : LinearRecurrence α)
def IsSolution (u : ℕ → α) :=
∀ n, u (n + E.order) = ∑ i, E.coeffs i * u (n + i)
#align linear_recurrence.is_solution LinearRecurrence.IsSolution
def mkSol (init : Fin E.order → α) : ℕ → α
| n =>
if h : n < E.order then init ⟨n, h⟩
else
∑ k : Fin E.order,
have _ : n - E.order + k < n := by
rw [add_comm, ← add_tsub_assoc_of_le (not_lt.mp h), tsub_lt_iff_left]
· exact add_lt_add_right k.is_lt n
· convert add_le_add (zero_le (k : ℕ)) (not_lt.mp h)
simp only [zero_add]
E.coeffs k * mkSol init (n - E.order + k)
#align linear_recurrence.mk_sol LinearRecurrence.mkSol
theorem is_sol_mkSol (init : Fin E.order → α) : E.IsSolution (E.mkSol init) := by
intro n
rw [mkSol]
simp
#align linear_recurrence.is_sol_mk_sol LinearRecurrence.is_sol_mkSol
| Mathlib/Algebra/LinearRecurrence.lean | 92 | 95 | theorem mkSol_eq_init (init : Fin E.order → α) : ∀ n : Fin E.order, E.mkSol init n = init n := by |
intro n
rw [mkSol]
simp only [n.is_lt, dif_pos, Fin.mk_val, Fin.eta]
|
import Mathlib.CategoryTheory.Monoidal.Free.Coherence
import Mathlib.Tactic.CategoryTheory.Coherence
import Mathlib.CategoryTheory.Closed.Monoidal
import Mathlib.Tactic.ApplyFun
#align_import category_theory.monoidal.rigid.basic from "leanprover-community/mathlib"@"3d7987cda72abc473c7cdbbb075170e9ac620042"
open CategoryTheory MonoidalCategory
universe v v₁ v₂ v₃ u u₁ u₂ u₃
noncomputable section
namespace CategoryTheory
variable {C : Type u₁} [Category.{v₁} C] [MonoidalCategory C]
class ExactPairing (X Y : C) where
coevaluation' : 𝟙_ C ⟶ X ⊗ Y
evaluation' : Y ⊗ X ⟶ 𝟙_ C
coevaluation_evaluation' :
Y ◁ coevaluation' ≫ (α_ _ _ _).inv ≫ evaluation' ▷ Y = (ρ_ Y).hom ≫ (λ_ Y).inv := by
aesop_cat
evaluation_coevaluation' :
coevaluation' ▷ X ≫ (α_ _ _ _).hom ≫ X ◁ evaluation' = (λ_ X).hom ≫ (ρ_ X).inv := by
aesop_cat
#align category_theory.exact_pairing CategoryTheory.ExactPairing
attribute [reassoc (attr := simp)] ExactPairing.coevaluation_evaluation
attribute [reassoc (attr := simp)] ExactPairing.evaluation_coevaluation
instance exactPairingUnit : ExactPairing (𝟙_ C) (𝟙_ C) where
coevaluation' := (ρ_ _).inv
evaluation' := (ρ_ _).hom
coevaluation_evaluation' := by rw [← id_tensorHom, ← tensorHom_id]; coherence
evaluation_coevaluation' := by rw [← id_tensorHom, ← tensorHom_id]; coherence
#align category_theory.exact_pairing_unit CategoryTheory.exactPairingUnit
class HasRightDual (X : C) where
rightDual : C
[exact : ExactPairing X rightDual]
#align category_theory.has_right_dual CategoryTheory.HasRightDual
class HasLeftDual (Y : C) where
leftDual : C
[exact : ExactPairing leftDual Y]
#align category_theory.has_left_dual CategoryTheory.HasLeftDual
attribute [instance] HasRightDual.exact
attribute [instance] HasLeftDual.exact
open ExactPairing HasRightDual HasLeftDual MonoidalCategory
@[inherit_doc] prefix:1024 "ᘁ" => leftDual
@[inherit_doc] postfix:1024 "ᘁ" => rightDual
instance hasRightDualUnit : HasRightDual (𝟙_ C) where
rightDual := 𝟙_ C
#align category_theory.has_right_dual_unit CategoryTheory.hasRightDualUnit
instance hasLeftDualUnit : HasLeftDual (𝟙_ C) where
leftDual := 𝟙_ C
#align category_theory.has_left_dual_unit CategoryTheory.hasLeftDualUnit
instance hasRightDualLeftDual {X : C} [HasLeftDual X] : HasRightDual ᘁX where
rightDual := X
#align category_theory.has_right_dual_left_dual CategoryTheory.hasRightDualLeftDual
instance hasLeftDualRightDual {X : C} [HasRightDual X] : HasLeftDual Xᘁ where
leftDual := X
#align category_theory.has_left_dual_right_dual CategoryTheory.hasLeftDualRightDual
@[simp]
theorem leftDual_rightDual {X : C} [HasRightDual X] : ᘁXᘁ = X :=
rfl
#align category_theory.left_dual_right_dual CategoryTheory.leftDual_rightDual
@[simp]
theorem rightDual_leftDual {X : C} [HasLeftDual X] : (ᘁX)ᘁ = X :=
rfl
#align category_theory.right_dual_left_dual CategoryTheory.rightDual_leftDual
def rightAdjointMate {X Y : C} [HasRightDual X] [HasRightDual Y] (f : X ⟶ Y) : Yᘁ ⟶ Xᘁ :=
(ρ_ _).inv ≫ _ ◁ η_ _ _ ≫ _ ◁ f ▷ _ ≫ (α_ _ _ _).inv ≫ ε_ _ _ ▷ _ ≫ (λ_ _).hom
#align category_theory.right_adjoint_mate CategoryTheory.rightAdjointMate
def leftAdjointMate {X Y : C} [HasLeftDual X] [HasLeftDual Y] (f : X ⟶ Y) : ᘁY ⟶ ᘁX :=
(λ_ _).inv ≫ η_ (ᘁX) X ▷ _ ≫ (_ ◁ f) ▷ _ ≫ (α_ _ _ _).hom ≫ _ ◁ ε_ _ _ ≫ (ρ_ _).hom
#align category_theory.left_adjoint_mate CategoryTheory.leftAdjointMate
@[inherit_doc] notation f "ᘁ" => rightAdjointMate f
@[inherit_doc] notation "ᘁ" f => leftAdjointMate f
@[simp]
theorem rightAdjointMate_id {X : C} [HasRightDual X] : (𝟙 X)ᘁ = 𝟙 (Xᘁ) := by
simp [rightAdjointMate]
#align category_theory.right_adjoint_mate_id CategoryTheory.rightAdjointMate_id
@[simp]
theorem leftAdjointMate_id {X : C} [HasLeftDual X] : (ᘁ(𝟙 X)) = 𝟙 (ᘁX) := by
simp [leftAdjointMate]
#align category_theory.left_adjoint_mate_id CategoryTheory.leftAdjointMate_id
theorem rightAdjointMate_comp {X Y Z : C} [HasRightDual X] [HasRightDual Y] {f : X ⟶ Y}
{g : Xᘁ ⟶ Z} :
fᘁ ≫ g =
(ρ_ (Yᘁ)).inv ≫
_ ◁ η_ X (Xᘁ) ≫ _ ◁ (f ⊗ g) ≫ (α_ (Yᘁ) Y Z).inv ≫ ε_ Y (Yᘁ) ▷ _ ≫ (λ_ Z).hom :=
calc
_ = 𝟙 _ ⊗≫ Yᘁ ◁ η_ X Xᘁ ≫ Yᘁ ◁ f ▷ Xᘁ ⊗≫ (ε_ Y Yᘁ ▷ Xᘁ ≫ 𝟙_ C ◁ g) ⊗≫ 𝟙 _ := by
dsimp only [rightAdjointMate]; coherence
_ = _ := by
rw [← whisker_exchange, tensorHom_def]; coherence
#align category_theory.right_adjoint_mate_comp CategoryTheory.rightAdjointMate_comp
theorem leftAdjointMate_comp {X Y Z : C} [HasLeftDual X] [HasLeftDual Y] {f : X ⟶ Y}
{g : (ᘁX) ⟶ Z} :
(ᘁf) ≫ g =
(λ_ _).inv ≫
η_ (ᘁX) X ▷ _ ≫ (g ⊗ f) ▷ _ ≫ (α_ _ _ _).hom ≫ _ ◁ ε_ _ _ ≫ (ρ_ _).hom :=
calc
_ = 𝟙 _ ⊗≫ η_ (ᘁX) X ▷ (ᘁY) ⊗≫ (ᘁX) ◁ f ▷ (ᘁY) ⊗≫ ((ᘁX) ◁ ε_ (ᘁY) Y ≫ g ▷ 𝟙_ C) ⊗≫ 𝟙 _ := by
dsimp only [leftAdjointMate]; coherence
_ = _ := by
rw [whisker_exchange, tensorHom_def']; coherence
#align category_theory.left_adjoint_mate_comp CategoryTheory.leftAdjointMate_comp
@[reassoc]
theorem comp_rightAdjointMate {X Y Z : C} [HasRightDual X] [HasRightDual Y] [HasRightDual Z]
{f : X ⟶ Y} {g : Y ⟶ Z} : (f ≫ g)ᘁ = gᘁ ≫ fᘁ := by
rw [rightAdjointMate_comp]
simp only [rightAdjointMate, comp_whiskerRight]
simp only [← Category.assoc]; congr 3; simp only [Category.assoc]
simp only [← MonoidalCategory.whiskerLeft_comp]; congr 2
symm
calc
_ = 𝟙 _ ⊗≫ (η_ Y Yᘁ ▷ 𝟙_ C ≫ (Y ⊗ Yᘁ) ◁ η_ X Xᘁ) ⊗≫ Y ◁ Yᘁ ◁ f ▷ Xᘁ ⊗≫
Y ◁ ε_ Y Yᘁ ▷ Xᘁ ⊗≫ g ▷ Xᘁ ⊗≫ 𝟙 _ := by
rw [tensorHom_def']; coherence
_ = η_ X Xᘁ ⊗≫ (η_ Y Yᘁ ▷ (X ⊗ Xᘁ) ≫ (Y ⊗ Yᘁ) ◁ f ▷ Xᘁ) ⊗≫
Y ◁ ε_ Y Yᘁ ▷ Xᘁ ⊗≫ g ▷ Xᘁ ⊗≫ 𝟙 _ := by
rw [← whisker_exchange]; coherence
_ = η_ X Xᘁ ⊗≫ f ▷ Xᘁ ⊗≫ (η_ Y Yᘁ ▷ Y ⊗≫ Y ◁ ε_ Y Yᘁ) ▷ Xᘁ ⊗≫ g ▷ Xᘁ ⊗≫ 𝟙 _ := by
rw [← whisker_exchange]; coherence
_ = η_ X Xᘁ ≫ f ▷ Xᘁ ≫ g ▷ Xᘁ := by
rw [evaluation_coevaluation'']; coherence
#align category_theory.comp_right_adjoint_mate CategoryTheory.comp_rightAdjointMate
@[reassoc]
theorem comp_leftAdjointMate {X Y Z : C} [HasLeftDual X] [HasLeftDual Y] [HasLeftDual Z] {f : X ⟶ Y}
{g : Y ⟶ Z} : (ᘁf ≫ g) = (ᘁg) ≫ ᘁf := by
rw [leftAdjointMate_comp]
simp only [leftAdjointMate, MonoidalCategory.whiskerLeft_comp]
simp only [← Category.assoc]; congr 3; simp only [Category.assoc]
simp only [← comp_whiskerRight]; congr 2
symm
calc
_ = 𝟙 _ ⊗≫ ((𝟙_ C) ◁ η_ (ᘁY) Y ≫ η_ (ᘁX) X ▷ ((ᘁY) ⊗ Y)) ⊗≫ (ᘁX) ◁ f ▷ (ᘁY) ▷ Y ⊗≫
(ᘁX) ◁ ε_ (ᘁY) Y ▷ Y ⊗≫ (ᘁX) ◁ g := by
rw [tensorHom_def]; coherence
_ = η_ (ᘁX) X ⊗≫ (((ᘁX) ⊗ X) ◁ η_ (ᘁY) Y ≫ ((ᘁX) ◁ f) ▷ ((ᘁY) ⊗ Y)) ⊗≫
(ᘁX) ◁ ε_ (ᘁY) Y ▷ Y ⊗≫ (ᘁX) ◁ g := by
rw [whisker_exchange]; coherence
_ = η_ (ᘁX) X ⊗≫ ((ᘁX) ◁ f) ⊗≫ (ᘁX) ◁ (Y ◁ η_ (ᘁY) Y ⊗≫ ε_ (ᘁY) Y ▷ Y) ⊗≫ (ᘁX) ◁ g := by
rw [whisker_exchange]; coherence
_ = η_ (ᘁX) X ≫ (ᘁX) ◁ f ≫ (ᘁX) ◁ g := by
rw [coevaluation_evaluation'']; coherence
#align category_theory.comp_left_adjoint_mate CategoryTheory.comp_leftAdjointMate
def tensorLeftHomEquiv (X Y Y' Z : C) [ExactPairing Y Y'] : (Y' ⊗ X ⟶ Z) ≃ (X ⟶ Y ⊗ Z) where
toFun f := (λ_ _).inv ≫ η_ _ _ ▷ _ ≫ (α_ _ _ _).hom ≫ _ ◁ f
invFun f := Y' ◁ f ≫ (α_ _ _ _).inv ≫ ε_ _ _ ▷ _ ≫ (λ_ _).hom
left_inv f := by
calc
_ = 𝟙 _ ⊗≫ Y' ◁ η_ Y Y' ▷ X ⊗≫ ((Y' ⊗ Y) ◁ f ≫ ε_ Y Y' ▷ Z) ⊗≫ 𝟙 _ := by
coherence
_ = 𝟙 _ ⊗≫ (Y' ◁ η_ Y Y' ⊗≫ ε_ Y Y' ▷ Y') ▷ X ⊗≫ f := by
rw [whisker_exchange]; coherence
_ = f := by
rw [coevaluation_evaluation'']; coherence
right_inv f := by
calc
_ = 𝟙 _ ⊗≫ (η_ Y Y' ▷ X ≫ (Y ⊗ Y') ◁ f) ⊗≫ Y ◁ ε_ Y Y' ▷ Z ⊗≫ 𝟙 _ := by
coherence
_ = f ⊗≫ (η_ Y Y' ▷ Y ⊗≫ Y ◁ ε_ Y Y') ▷ Z ⊗≫ 𝟙 _ := by
rw [← whisker_exchange]; coherence
_ = f := by
rw [evaluation_coevaluation'']; coherence
#align category_theory.tensor_left_hom_equiv CategoryTheory.tensorLeftHomEquiv
def tensorRightHomEquiv (X Y Y' Z : C) [ExactPairing Y Y'] : (X ⊗ Y ⟶ Z) ≃ (X ⟶ Z ⊗ Y') where
toFun f := (ρ_ _).inv ≫ _ ◁ η_ _ _ ≫ (α_ _ _ _).inv ≫ f ▷ _
invFun f := f ▷ _ ≫ (α_ _ _ _).hom ≫ _ ◁ ε_ _ _ ≫ (ρ_ _).hom
left_inv f := by
calc
_ = 𝟙 _ ⊗≫ X ◁ η_ Y Y' ▷ Y ⊗≫ (f ▷ (Y' ⊗ Y) ≫ Z ◁ ε_ Y Y') ⊗≫ 𝟙 _ := by
coherence
_ = 𝟙 _ ⊗≫ X ◁ (η_ Y Y' ▷ Y ⊗≫ Y ◁ ε_ Y Y') ⊗≫ f := by
rw [← whisker_exchange]; coherence
_ = f := by
rw [evaluation_coevaluation'']; coherence
right_inv f := by
calc
_ = 𝟙 _ ⊗≫ (X ◁ η_ Y Y' ≫ f ▷ (Y ⊗ Y')) ⊗≫ Z ◁ ε_ Y Y' ▷ Y' ⊗≫ 𝟙 _ := by
coherence
_ = f ⊗≫ Z ◁ (Y' ◁ η_ Y Y' ⊗≫ ε_ Y Y' ▷ Y') ⊗≫ 𝟙 _ := by
rw [whisker_exchange]; coherence
_ = f := by
rw [coevaluation_evaluation'']; coherence
#align category_theory.tensor_right_hom_equiv CategoryTheory.tensorRightHomEquiv
theorem tensorLeftHomEquiv_naturality {X Y Y' Z Z' : C} [ExactPairing Y Y'] (f : Y' ⊗ X ⟶ Z)
(g : Z ⟶ Z') :
(tensorLeftHomEquiv X Y Y' Z') (f ≫ g) = (tensorLeftHomEquiv X Y Y' Z) f ≫ Y ◁ g := by
simp [tensorLeftHomEquiv]
#align category_theory.tensor_left_hom_equiv_naturality CategoryTheory.tensorLeftHomEquiv_naturality
| Mathlib/CategoryTheory/Monoidal/Rigid/Basic.lean | 339 | 343 | theorem tensorLeftHomEquiv_symm_naturality {X X' Y Y' Z : C} [ExactPairing Y Y'] (f : X ⟶ X')
(g : X' ⟶ Y ⊗ Z) :
(tensorLeftHomEquiv X Y Y' Z).symm (f ≫ g) =
_ ◁ f ≫ (tensorLeftHomEquiv X' Y Y' Z).symm g := by |
simp [tensorLeftHomEquiv]
|
import Mathlib.CategoryTheory.GlueData
import Mathlib.Topology.Category.TopCat.Limits.Pullbacks
import Mathlib.Topology.Category.TopCat.Opens
import Mathlib.Tactic.Generalize
import Mathlib.CategoryTheory.Elementwise
#align_import topology.gluing from "leanprover-community/mathlib"@"178a32653e369dce2da68dc6b2694e385d484ef1"
noncomputable section
open TopologicalSpace CategoryTheory
universe v u
open CategoryTheory.Limits
namespace TopCat
-- porting note (#5171): removed @[nolint has_nonempty_instance]
structure GlueData extends GlueData TopCat where
f_open : ∀ i j, OpenEmbedding (f i j)
f_mono := fun i j => (TopCat.mono_iff_injective _).mpr (f_open i j).toEmbedding.inj
set_option linter.uppercaseLean3 false in
#align Top.glue_data TopCat.GlueData
namespace GlueData
variable (D : GlueData.{u})
local notation "𝖣" => D.toGlueData
theorem π_surjective : Function.Surjective 𝖣.π :=
(TopCat.epi_iff_surjective 𝖣.π).mp inferInstance
set_option linter.uppercaseLean3 false in
#align Top.glue_data.π_surjective TopCat.GlueData.π_surjective
theorem isOpen_iff (U : Set 𝖣.glued) : IsOpen U ↔ ∀ i, IsOpen (𝖣.ι i ⁻¹' U) := by
delta CategoryTheory.GlueData.ι
simp_rw [← Multicoequalizer.ι_sigmaπ 𝖣.diagram]
rw [← (homeoOfIso (Multicoequalizer.isoCoequalizer 𝖣.diagram).symm).isOpen_preimage]
rw [coequalizer_isOpen_iff]
dsimp only [GlueData.diagram_l, GlueData.diagram_left, GlueData.diagram_r, GlueData.diagram_right,
parallelPair_obj_one]
rw [colimit_isOpen_iff.{_,u}] -- Porting note: changed `.{u}` to `.{_,u}`. fun fact: the proof
-- breaks down if this `rw` is merged with the `rw` above.
constructor
· intro h j; exact h ⟨j⟩
· intro h j; cases j; apply h
set_option linter.uppercaseLean3 false in
#align Top.glue_data.is_open_iff TopCat.GlueData.isOpen_iff
theorem ι_jointly_surjective (x : 𝖣.glued) : ∃ (i : _) (y : D.U i), 𝖣.ι i y = x :=
𝖣.ι_jointly_surjective (forget TopCat) x
set_option linter.uppercaseLean3 false in
#align Top.glue_data.ι_jointly_surjective TopCat.GlueData.ι_jointly_surjective
def Rel (a b : Σ i, ((D.U i : TopCat) : Type _)) : Prop :=
a = b ∨ ∃ x : D.V (a.1, b.1), D.f _ _ x = a.2 ∧ D.f _ _ (D.t _ _ x) = b.2
set_option linter.uppercaseLean3 false in
#align Top.glue_data.rel TopCat.GlueData.Rel
theorem rel_equiv : Equivalence D.Rel :=
⟨fun x => Or.inl (refl x), by
rintro a b (⟨⟨⟩⟩ | ⟨x, e₁, e₂⟩)
exacts [Or.inl rfl, Or.inr ⟨D.t _ _ x, e₂, by erw [← e₁, D.t_inv_apply]⟩], by
-- previous line now `erw` after #13170
rintro ⟨i, a⟩ ⟨j, b⟩ ⟨k, c⟩ (⟨⟨⟩⟩ | ⟨x, e₁, e₂⟩)
· exact id
rintro (⟨⟨⟩⟩ | ⟨y, e₃, e₄⟩)
· exact Or.inr ⟨x, e₁, e₂⟩
let z := (pullbackIsoProdSubtype (D.f j i) (D.f j k)).inv ⟨⟨_, _⟩, e₂.trans e₃.symm⟩
have eq₁ : (D.t j i) ((pullback.fst : _ ⟶ D.V (j, i)) z) = x := by
dsimp only [coe_of, z]
erw [pullbackIsoProdSubtype_inv_fst_apply, D.t_inv_apply]-- now `erw` after #13170
have eq₂ : (pullback.snd : _ ⟶ D.V _) z = y := pullbackIsoProdSubtype_inv_snd_apply _ _ _
clear_value z
right
use (pullback.fst : _ ⟶ D.V (i, k)) (D.t' _ _ _ z)
dsimp only at *
substs eq₁ eq₂ e₁ e₃ e₄
have h₁ : D.t' j i k ≫ pullback.fst ≫ D.f i k = pullback.fst ≫ D.t j i ≫ D.f i j := by
rw [← 𝖣.t_fac_assoc]; congr 1; exact pullback.condition
have h₂ : D.t' j i k ≫ pullback.fst ≫ D.t i k ≫ D.f k i = pullback.snd ≫ D.t j k ≫ D.f k j := by
rw [← 𝖣.t_fac_assoc]
apply @Epi.left_cancellation _ _ _ _ (D.t' k j i)
rw [𝖣.cocycle_assoc, 𝖣.t_fac_assoc, 𝖣.t_inv_assoc]
exact pullback.condition.symm
exact ⟨ContinuousMap.congr_fun h₁ z, ContinuousMap.congr_fun h₂ z⟩⟩
set_option linter.uppercaseLean3 false in
#align Top.glue_data.rel_equiv TopCat.GlueData.rel_equiv
open CategoryTheory.Limits.WalkingParallelPair
theorem eqvGen_of_π_eq
-- Porting note: was `{x y : ∐ D.U} (h : 𝖣.π x = 𝖣.π y)`
{x y : sigmaObj (β := D.toGlueData.J) (C := TopCat) D.toGlueData.U}
(h : 𝖣.π x = 𝖣.π y) :
EqvGen
-- Porting note: was (Types.CoequalizerRel 𝖣.diagram.fstSigmaMap 𝖣.diagram.sndSigmaMap)
(Types.CoequalizerRel
(X := sigmaObj (β := D.toGlueData.diagram.L) (C := TopCat) (D.toGlueData.diagram).left)
(Y := sigmaObj (β := D.toGlueData.diagram.R) (C := TopCat) (D.toGlueData.diagram).right)
𝖣.diagram.fstSigmaMap 𝖣.diagram.sndSigmaMap)
x y := by
delta GlueData.π Multicoequalizer.sigmaπ at h
-- Porting note: inlined `inferInstance` instead of leaving as a side goal.
replace h := (TopCat.mono_iff_injective (Multicoequalizer.isoCoequalizer 𝖣.diagram).inv).mp
inferInstance h
let diagram := parallelPair 𝖣.diagram.fstSigmaMap 𝖣.diagram.sndSigmaMap ⋙ forget _
have : colimit.ι diagram one x = colimit.ι diagram one y := by
dsimp only [coequalizer.π, ContinuousMap.toFun_eq_coe] at h
-- This used to be `rw`, but we need `erw` after leanprover/lean4#2644
erw [← ι_preservesColimitsIso_hom, forget_map_eq_coe, types_comp_apply, h]
simp
rfl
have :
(colimit.ι diagram _ ≫ colim.map _ ≫ (colimit.isoColimitCocone _).hom) _ =
(colimit.ι diagram _ ≫ colim.map _ ≫ (colimit.isoColimitCocone _).hom) _ :=
(congr_arg
(colim.map (diagramIsoParallelPair diagram).hom ≫
(colimit.isoColimitCocone (Types.coequalizerColimit _ _)).hom)
this :
_)
-- Porting note: was
-- simp only [eqToHom_refl, types_comp_apply, colimit.ι_map_assoc,
-- diagramIsoParallelPair_hom_app, colimit.isoColimitCocone_ι_hom, types_id_apply] at this
-- See https://github.com/leanprover-community/mathlib4/issues/5026
rw [colimit.ι_map_assoc, diagramIsoParallelPair_hom_app, eqToHom_refl,
colimit.isoColimitCocone_ι_hom, types_comp_apply, types_id_apply, types_comp_apply,
types_id_apply] at this
exact Quot.eq.1 this
set_option linter.uppercaseLean3 false in
#align Top.glue_data.eqv_gen_of_π_eq TopCat.GlueData.eqvGen_of_π_eq
theorem ι_eq_iff_rel (i j : D.J) (x : D.U i) (y : D.U j) :
𝖣.ι i x = 𝖣.ι j y ↔ D.Rel ⟨i, x⟩ ⟨j, y⟩ := by
constructor
· delta GlueData.ι
simp_rw [← Multicoequalizer.ι_sigmaπ]
intro h
rw [←
show _ = Sigma.mk i x from ConcreteCategory.congr_hom (sigmaIsoSigma.{_, u} D.U).inv_hom_id _]
rw [←
show _ = Sigma.mk j y from ConcreteCategory.congr_hom (sigmaIsoSigma.{_, u} D.U).inv_hom_id _]
change InvImage D.Rel (sigmaIsoSigma.{_, u} D.U).hom _ _
rw [← (InvImage.equivalence _ _ D.rel_equiv).eqvGen_iff]
refine EqvGen.mono ?_ (D.eqvGen_of_π_eq h : _)
rintro _ _ ⟨x⟩
obtain ⟨⟨⟨i, j⟩, y⟩, rfl⟩ :=
(ConcreteCategory.bijective_of_isIso (sigmaIsoSigma.{u, u} _).inv).2 x
unfold InvImage MultispanIndex.fstSigmaMap MultispanIndex.sndSigmaMap
simp only [forget_map_eq_coe]
erw [TopCat.comp_app, sigmaIsoSigma_inv_apply, ← comp_apply, ← comp_apply,
colimit.ι_desc_assoc, ← comp_apply, ← comp_apply, colimit.ι_desc_assoc]
-- previous line now `erw` after #13170
erw [sigmaIsoSigma_hom_ι_apply, sigmaIsoSigma_hom_ι_apply]
exact Or.inr ⟨y, ⟨rfl, rfl⟩⟩
· rintro (⟨⟨⟩⟩ | ⟨z, e₁, e₂⟩)
· rfl
dsimp only at *
-- Porting note: there were `subst e₁` and `subst e₂`, instead of the `rw`
rw [← e₁, ← e₂] at *
erw [D.glue_condition_apply] -- now `erw` after #13170
rfl -- now `rfl` after #13170
set_option linter.uppercaseLean3 false in
#align Top.glue_data.ι_eq_iff_rel TopCat.GlueData.ι_eq_iff_rel
theorem ι_injective (i : D.J) : Function.Injective (𝖣.ι i) := by
intro x y h
rcases (D.ι_eq_iff_rel _ _ _ _).mp h with (⟨⟨⟩⟩ | ⟨_, e₁, e₂⟩)
· rfl
· dsimp only at *
-- Porting note: there were `cases e₁` and `cases e₂`, instead of the `rw`
rw [← e₁, ← e₂]
simp
set_option linter.uppercaseLean3 false in
#align Top.glue_data.ι_injective TopCat.GlueData.ι_injective
instance ι_mono (i : D.J) : Mono (𝖣.ι i) :=
(TopCat.mono_iff_injective _).mpr (D.ι_injective _)
set_option linter.uppercaseLean3 false in
#align Top.glue_data.ι_mono TopCat.GlueData.ι_mono
theorem image_inter (i j : D.J) :
Set.range (𝖣.ι i) ∩ Set.range (𝖣.ι j) = Set.range (D.f i j ≫ 𝖣.ι _) := by
ext x
constructor
· rintro ⟨⟨x₁, eq₁⟩, ⟨x₂, eq₂⟩⟩
obtain ⟨⟨⟩⟩ | ⟨y, e₁, -⟩ := (D.ι_eq_iff_rel _ _ _ _).mp (eq₁.trans eq₂.symm)
· exact ⟨inv (D.f i i) x₁, by
-- porting note (#10745): was `simp [eq₁]`
-- See https://github.com/leanprover-community/mathlib4/issues/5026
rw [TopCat.comp_app]
erw [CategoryTheory.IsIso.inv_hom_id_apply]
rw [eq₁]⟩
· -- Porting note: was
-- dsimp only at *; substs e₁ eq₁; exact ⟨y, by simp⟩
dsimp only at *
substs eq₁
exact ⟨y, by simp [e₁]⟩
· rintro ⟨x, hx⟩
refine ⟨⟨D.f i j x, hx⟩, ⟨D.f j i (D.t _ _ x), ?_⟩⟩
erw [D.glue_condition_apply] -- now `erw` after #13170
exact hx
set_option linter.uppercaseLean3 false in
#align Top.glue_data.image_inter TopCat.GlueData.image_inter
theorem preimage_range (i j : D.J) : 𝖣.ι j ⁻¹' Set.range (𝖣.ι i) = Set.range (D.f j i) := by
rw [← Set.preimage_image_eq (Set.range (D.f j i)) (D.ι_injective j), ← Set.image_univ, ←
Set.image_univ, ← Set.image_comp, ← coe_comp, Set.image_univ, Set.image_univ, ← image_inter,
Set.preimage_range_inter]
set_option linter.uppercaseLean3 false in
#align Top.glue_data.preimage_range TopCat.GlueData.preimage_range
theorem preimage_image_eq_image (i j : D.J) (U : Set (𝖣.U i)) :
𝖣.ι j ⁻¹' (𝖣.ι i '' U) = D.f _ _ '' ((D.t j i ≫ D.f _ _) ⁻¹' U) := by
have : D.f _ _ ⁻¹' (𝖣.ι j ⁻¹' (𝖣.ι i '' U)) = (D.t j i ≫ D.f _ _) ⁻¹' U := by
ext x
conv_rhs => rw [← Set.preimage_image_eq U (D.ι_injective _)]
generalize 𝖣.ι i '' U = U' -- next 4 lines were `simp` before #13170
simp only [GlueData.diagram_l, GlueData.diagram_r, Set.mem_preimage, coe_comp,
Function.comp_apply]
erw [D.glue_condition_apply]
rfl
rw [← this, Set.image_preimage_eq_inter_range]
symm
apply Set.inter_eq_self_of_subset_left
rw [← D.preimage_range i j]
exact Set.preimage_mono (Set.image_subset_range _ _)
set_option linter.uppercaseLean3 false in
#align Top.glue_data.preimage_image_eq_image TopCat.GlueData.preimage_image_eq_image
theorem preimage_image_eq_image' (i j : D.J) (U : Set (𝖣.U i)) :
𝖣.ι j ⁻¹' (𝖣.ι i '' U) = (D.t i j ≫ D.f _ _) '' (D.f _ _ ⁻¹' U) := by
convert D.preimage_image_eq_image i j U using 1
rw [coe_comp, coe_comp]
-- Porting note: `show` was not needed, since `rw [← Set.image_image]` worked.
show (fun x => ((forget TopCat).map _ ((forget TopCat).map _ x))) '' _ = _
rw [← Set.image_image]
-- Porting note: `congr 1` was here, instead of `congr_arg`, however, it did nothing.
refine congr_arg ?_ ?_
rw [← Set.eq_preimage_iff_image_eq, Set.preimage_preimage]
· change _ = (D.t i j ≫ D.t j i ≫ _) ⁻¹' _
rw [𝖣.t_inv_assoc]
rw [← isIso_iff_bijective]
apply (forget TopCat).map_isIso
set_option linter.uppercaseLean3 false in
#align Top.glue_data.preimage_image_eq_image' TopCat.GlueData.preimage_image_eq_image'
-- Porting note: the goal was simply `IsOpen (𝖣.ι i '' U)`.
-- I had to manually add the explicit type ascription.
theorem open_image_open (i : D.J) (U : Opens (𝖣.U i)) : IsOpen (𝖣.ι i '' (U : Set (D.U i))) := by
rw [isOpen_iff]
intro j
rw [preimage_image_eq_image]
apply (D.f_open _ _).isOpenMap
apply (D.t j i ≫ D.f i j).continuous_toFun.isOpen_preimage
exact U.isOpen
set_option linter.uppercaseLean3 false in
#align Top.glue_data.open_image_open TopCat.GlueData.open_image_open
theorem ι_openEmbedding (i : D.J) : OpenEmbedding (𝖣.ι i) :=
openEmbedding_of_continuous_injective_open (𝖣.ι i).continuous_toFun (D.ι_injective i) fun U h =>
D.open_image_open i ⟨U, h⟩
set_option linter.uppercaseLean3 false in
#align Top.glue_data.ι_open_embedding TopCat.GlueData.ι_openEmbedding
-- Porting note(#5171): removed `@[nolint has_nonempty_instance]`
structure MkCore where
{J : Type u}
U : J → TopCat.{u}
V : ∀ i, J → Opens (U i)
t : ∀ i j, (Opens.toTopCat _).obj (V i j) ⟶ (Opens.toTopCat _).obj (V j i)
V_id : ∀ i, V i i = ⊤
t_id : ∀ i, ⇑(t i i) = id
t_inter : ∀ ⦃i j⦄ (k) (x : V i j), ↑x ∈ V i k → (((↑) : (V j i) → (U j)) (t i j x)) ∈ V j k
cocycle :
∀ (i j k) (x : V i j) (h : ↑x ∈ V i k),
-- Porting note: the underscore in the next line was `↑(t i j x)`, but Lean type-mismatched
(((↑) : (V k j) → (U k)) (t j k ⟨_, t_inter k x h⟩)) = ((↑) : (V k i) → (U k)) (t i k ⟨x, h⟩)
set_option linter.uppercaseLean3 false in
#align Top.glue_data.mk_core TopCat.GlueData.MkCore
theorem MkCore.t_inv (h : MkCore) (i j : h.J) (x : h.V j i) : h.t i j ((h.t j i) x) = x := by
have := h.cocycle j i j x ?_
· rw [h.t_id] at this
· convert Subtype.eq this
rw [h.V_id]
trivial
set_option linter.uppercaseLean3 false in
#align Top.glue_data.mk_core.t_inv TopCat.GlueData.MkCore.t_inv
instance (h : MkCore.{u}) (i j : h.J) : IsIso (h.t i j) := by
use h.t j i; constructor <;> ext1; exacts [h.t_inv _ _ _, h.t_inv _ _ _]
def MkCore.t' (h : MkCore.{u}) (i j k : h.J) :
pullback (h.V i j).inclusion (h.V i k).inclusion ⟶
pullback (h.V j k).inclusion (h.V j i).inclusion := by
refine (pullbackIsoProdSubtype _ _).hom ≫ ⟨?_, ?_⟩ ≫ (pullbackIsoProdSubtype _ _).inv
· intro x
refine ⟨⟨⟨(h.t i j x.1.1).1, ?_⟩, h.t i j x.1.1⟩, rfl⟩
rcases x with ⟨⟨⟨x, hx⟩, ⟨x', hx'⟩⟩, rfl : x = x'⟩
exact h.t_inter _ ⟨x, hx⟩ hx'
-- Porting note: was `continuity`, see https://github.com/leanprover-community/mathlib4/issues/5030
have : Continuous (h.t i j) := map_continuous (self := ContinuousMap.toContinuousMapClass) _
set_option tactic.skipAssignedInstances false in
exact ((Continuous.subtype_mk (by continuity) _).prod_mk (by continuity)).subtype_mk _
set_option linter.uppercaseLean3 false in
#align Top.glue_data.mk_core.t' TopCat.GlueData.MkCore.t'
def mk' (h : MkCore.{u}) : TopCat.GlueData where
J := h.J
U := h.U
V i := (Opens.toTopCat _).obj (h.V i.1 i.2)
f i j := (h.V i j).inclusion
f_id i := by
-- Porting note (#12129): additional beta reduction needed
beta_reduce
exact (h.V_id i).symm ▸ (Opens.inclusionTopIso (h.U i)).isIso_hom
f_open := fun i j : h.J => (h.V i j).openEmbedding
t := h.t
t_id i := by ext; erw [h.t_id]; rfl -- now `erw` after #13170
t' := h.t'
t_fac i j k := by
delta MkCore.t'
rw [Category.assoc, Category.assoc, pullbackIsoProdSubtype_inv_snd, ← Iso.eq_inv_comp,
pullbackIsoProdSubtype_inv_fst_assoc]
ext ⟨⟨⟨x, hx⟩, ⟨x', hx'⟩⟩, rfl : x = x'⟩
rfl
cocycle i j k := by
delta MkCore.t'
simp_rw [← Category.assoc]
rw [Iso.comp_inv_eq]
simp only [Iso.inv_hom_id_assoc, Category.assoc, Category.id_comp]
rw [← Iso.eq_inv_comp, Iso.inv_hom_id]
ext1 ⟨⟨⟨x, hx⟩, ⟨x', hx'⟩⟩, rfl : x = x'⟩
-- The next 9 tactics (up to `convert ...` were a single `rw` before leanprover/lean4#2644
-- rw [comp_app, ContinuousMap.coe_mk, comp_app, id_app, ContinuousMap.coe_mk, Subtype.mk_eq_mk,
-- Prod.mk.inj_iff, Subtype.mk_eq_mk, Subtype.ext_iff, and_self_iff]
erw [comp_app] --, comp_app, id_app] -- now `erw` after #13170
-- erw [ContinuousMap.coe_mk]
conv_lhs => erw [ContinuousMap.coe_mk]
erw [id_app]
rw [ContinuousMap.coe_mk]
erw [Subtype.mk_eq_mk]
rw [Prod.mk.inj_iff]
erw [Subtype.mk_eq_mk]
rw [Subtype.ext_iff]
rw [and_self_iff]
convert congr_arg Subtype.val (h.t_inv k i ⟨x, hx'⟩) using 3
refine Subtype.ext ?_
exact h.cocycle i j k ⟨x, hx⟩ hx'
-- Porting note: was not necessary in mathlib3
f_mono i j := (TopCat.mono_iff_injective _).mpr fun x y h => Subtype.ext h
set_option linter.uppercaseLean3 false in
#align Top.glue_data.mk' TopCat.GlueData.mk'
variable {α : Type u} [TopologicalSpace α] {J : Type u} (U : J → Opens α)
@[simps! toGlueData_J toGlueData_U toGlueData_V toGlueData_t toGlueData_f]
def ofOpenSubsets : TopCat.GlueData.{u} :=
mk'.{u}
{ J
U := fun i => (Opens.toTopCat <| TopCat.of α).obj (U i)
V := fun i j => (Opens.map <| Opens.inclusion _).obj (U j)
t := fun i j => ⟨fun x => ⟨⟨x.1.1, x.2⟩, x.1.2⟩, by
-- Porting note: was `continuity`, see https://github.com/leanprover-community/mathlib4/issues/5030
refine Continuous.subtype_mk ?_ ?_
refine Continuous.subtype_mk ?_ ?_
continuity⟩
V_id := fun i => by
ext
-- Porting note: no longer needed `cases U i`!
simp
t_id := fun i => by ext; rfl
t_inter := fun i j k x hx => hx
cocycle := fun i j k x h => rfl }
set_option linter.uppercaseLean3 false in
#align Top.glue_data.of_open_subsets TopCat.GlueData.ofOpenSubsets
def fromOpenSubsetsGlue : (ofOpenSubsets U).toGlueData.glued ⟶ TopCat.of α :=
Multicoequalizer.desc _ _ (fun x => Opens.inclusion _) (by rintro ⟨i, j⟩; ext x; rfl)
set_option linter.uppercaseLean3 false in
#align Top.glue_data.from_open_subsets_glue TopCat.GlueData.fromOpenSubsetsGlue
-- Porting note: `elementwise` here produces a bad lemma,
-- where too much has been simplified, despite the `nosimp`.
@[simp, elementwise nosimp]
theorem ι_fromOpenSubsetsGlue (i : J) :
(ofOpenSubsets U).toGlueData.ι i ≫ fromOpenSubsetsGlue U = Opens.inclusion _ :=
Multicoequalizer.π_desc _ _ _ _ _
set_option linter.uppercaseLean3 false in
#align Top.glue_data.ι_from_open_subsets_glue TopCat.GlueData.ι_fromOpenSubsetsGlue
| Mathlib/Topology/Gluing.lean | 488 | 499 | theorem fromOpenSubsetsGlue_injective : Function.Injective (fromOpenSubsetsGlue U) := by |
intro x y e
obtain ⟨i, ⟨x, hx⟩, rfl⟩ := (ofOpenSubsets U).ι_jointly_surjective x
obtain ⟨j, ⟨y, hy⟩, rfl⟩ := (ofOpenSubsets U).ι_jointly_surjective y
-- Porting note: now it is `erw`, it was `rw`
-- see the porting note on `ι_fromOpenSubsetsGlue`
erw [ι_fromOpenSubsetsGlue_apply, ι_fromOpenSubsetsGlue_apply] at e
change x = y at e
subst e
rw [(ofOpenSubsets U).ι_eq_iff_rel]
right
exact ⟨⟨⟨x, hx⟩, hy⟩, rfl, rfl⟩
|
import Mathlib.Algebra.Polynomial.AlgebraMap
import Mathlib.Algebra.Polynomial.BigOperators
import Mathlib.Algebra.Polynomial.Degree.Lemmas
import Mathlib.Algebra.Polynomial.Div
#align_import data.polynomial.ring_division from "leanprover-community/mathlib"@"8efcf8022aac8e01df8d302dcebdbc25d6a886c8"
noncomputable section
open Polynomial
open Finset
namespace Polynomial
universe u v w z
variable {R : Type u} {S : Type v} {T : Type w} {a b : R} {n : ℕ}
section NoZeroDivisors
variable [Semiring R] [NoZeroDivisors R] {p q : R[X]}
instance : NoZeroDivisors R[X] where
eq_zero_or_eq_zero_of_mul_eq_zero h := by
rw [← leadingCoeff_eq_zero, ← leadingCoeff_eq_zero]
refine eq_zero_or_eq_zero_of_mul_eq_zero ?_
rw [← leadingCoeff_zero, ← leadingCoeff_mul, h]
theorem natDegree_mul (hp : p ≠ 0) (hq : q ≠ 0) : (p*q).natDegree = p.natDegree + q.natDegree := by
rw [← Nat.cast_inj (R := WithBot ℕ), ← degree_eq_natDegree (mul_ne_zero hp hq),
Nat.cast_add, ← degree_eq_natDegree hp, ← degree_eq_natDegree hq, degree_mul]
#align polynomial.nat_degree_mul Polynomial.natDegree_mul
theorem trailingDegree_mul : (p * q).trailingDegree = p.trailingDegree + q.trailingDegree := by
by_cases hp : p = 0
· rw [hp, zero_mul, trailingDegree_zero, top_add]
by_cases hq : q = 0
· rw [hq, mul_zero, trailingDegree_zero, add_top]
· rw [trailingDegree_eq_natTrailingDegree hp, trailingDegree_eq_natTrailingDegree hq,
trailingDegree_eq_natTrailingDegree (mul_ne_zero hp hq), natTrailingDegree_mul hp hq]
apply WithTop.coe_add
#align polynomial.trailing_degree_mul Polynomial.trailingDegree_mul
@[simp]
theorem natDegree_pow (p : R[X]) (n : ℕ) : natDegree (p ^ n) = n * natDegree p := by
classical
obtain rfl | hp := eq_or_ne p 0
· obtain rfl | hn := eq_or_ne n 0 <;> simp [*]
exact natDegree_pow' $ by
rw [← leadingCoeff_pow, Ne, leadingCoeff_eq_zero]; exact pow_ne_zero _ hp
#align polynomial.nat_degree_pow Polynomial.natDegree_pow
theorem degree_le_mul_left (p : R[X]) (hq : q ≠ 0) : degree p ≤ degree (p * q) := by
classical
exact if hp : p = 0 then by simp only [hp, zero_mul, le_refl]
else by
rw [degree_mul, degree_eq_natDegree hp, degree_eq_natDegree hq];
exact WithBot.coe_le_coe.2 (Nat.le_add_right _ _)
#align polynomial.degree_le_mul_left Polynomial.degree_le_mul_left
theorem natDegree_le_of_dvd {p q : R[X]} (h1 : p ∣ q) (h2 : q ≠ 0) : p.natDegree ≤ q.natDegree := by
rcases h1 with ⟨q, rfl⟩; rw [mul_ne_zero_iff] at h2
rw [natDegree_mul h2.1 h2.2]; exact Nat.le_add_right _ _
#align polynomial.nat_degree_le_of_dvd Polynomial.natDegree_le_of_dvd
theorem degree_le_of_dvd {p q : R[X]} (h1 : p ∣ q) (h2 : q ≠ 0) : degree p ≤ degree q := by
rcases h1 with ⟨q, rfl⟩; rw [mul_ne_zero_iff] at h2
exact degree_le_mul_left p h2.2
#align polynomial.degree_le_of_dvd Polynomial.degree_le_of_dvd
| Mathlib/Algebra/Polynomial/RingDivision.lean | 166 | 169 | theorem eq_zero_of_dvd_of_degree_lt {p q : R[X]} (h₁ : p ∣ q) (h₂ : degree q < degree p) :
q = 0 := by |
by_contra hc
exact (lt_iff_not_ge _ _).mp h₂ (degree_le_of_dvd h₁ hc)
|
import Mathlib.MeasureTheory.Measure.MeasureSpace
open scoped ENNReal NNReal Topology
open Set MeasureTheory Measure Filter MeasurableSpace ENNReal Function
variable {R α β δ γ ι : Type*}
@[simp]
theorem ae_restrict_iUnion_eq [Countable ι] (s : ι → Set α) :
ae (μ.restrict (⋃ i, s i)) = ⨆ i, ae (μ.restrict (s i)) :=
le_antisymm ((ae_sum_eq fun i => μ.restrict (s i)) ▸ ae_mono restrict_iUnion_le) <|
iSup_le fun i => ae_mono <| restrict_mono (subset_iUnion s i) le_rfl
#align measure_theory.ae_restrict_Union_eq MeasureTheory.ae_restrict_iUnion_eq
@[simp]
theorem ae_restrict_union_eq (s t : Set α) :
ae (μ.restrict (s ∪ t)) = ae (μ.restrict s) ⊔ ae (μ.restrict t) := by
simp [union_eq_iUnion, iSup_bool_eq]
#align measure_theory.ae_restrict_union_eq MeasureTheory.ae_restrict_union_eq
theorem ae_restrict_biUnion_eq (s : ι → Set α) {t : Set ι} (ht : t.Countable) :
ae (μ.restrict (⋃ i ∈ t, s i)) = ⨆ i ∈ t, ae (μ.restrict (s i)) := by
haveI := ht.to_subtype
rw [biUnion_eq_iUnion, ae_restrict_iUnion_eq, ← iSup_subtype'']
#align measure_theory.ae_restrict_bUnion_eq MeasureTheory.ae_restrict_biUnion_eq
theorem ae_restrict_biUnion_finset_eq (s : ι → Set α) (t : Finset ι) :
ae (μ.restrict (⋃ i ∈ t, s i)) = ⨆ i ∈ t, ae (μ.restrict (s i)) :=
ae_restrict_biUnion_eq s t.countable_toSet
#align measure_theory.ae_restrict_bUnion_finset_eq MeasureTheory.ae_restrict_biUnion_finset_eq
theorem ae_restrict_iUnion_iff [Countable ι] (s : ι → Set α) (p : α → Prop) :
(∀ᵐ x ∂μ.restrict (⋃ i, s i), p x) ↔ ∀ i, ∀ᵐ x ∂μ.restrict (s i), p x := by simp
#align measure_theory.ae_restrict_Union_iff MeasureTheory.ae_restrict_iUnion_iff
theorem ae_restrict_union_iff (s t : Set α) (p : α → Prop) :
(∀ᵐ x ∂μ.restrict (s ∪ t), p x) ↔ (∀ᵐ x ∂μ.restrict s, p x) ∧ ∀ᵐ x ∂μ.restrict t, p x := by simp
#align measure_theory.ae_restrict_union_iff MeasureTheory.ae_restrict_union_iff
theorem ae_restrict_biUnion_iff (s : ι → Set α) {t : Set ι} (ht : t.Countable) (p : α → Prop) :
(∀ᵐ x ∂μ.restrict (⋃ i ∈ t, s i), p x) ↔ ∀ i ∈ t, ∀ᵐ x ∂μ.restrict (s i), p x := by
simp_rw [Filter.Eventually, ae_restrict_biUnion_eq s ht, mem_iSup]
#align measure_theory.ae_restrict_bUnion_iff MeasureTheory.ae_restrict_biUnion_iff
@[simp]
theorem ae_restrict_biUnion_finset_iff (s : ι → Set α) (t : Finset ι) (p : α → Prop) :
(∀ᵐ x ∂μ.restrict (⋃ i ∈ t, s i), p x) ↔ ∀ i ∈ t, ∀ᵐ x ∂μ.restrict (s i), p x := by
simp_rw [Filter.Eventually, ae_restrict_biUnion_finset_eq s, mem_iSup]
#align measure_theory.ae_restrict_bUnion_finset_iff MeasureTheory.ae_restrict_biUnion_finset_iff
theorem ae_eq_restrict_iUnion_iff [Countable ι] (s : ι → Set α) (f g : α → δ) :
f =ᵐ[μ.restrict (⋃ i, s i)] g ↔ ∀ i, f =ᵐ[μ.restrict (s i)] g := by
simp_rw [EventuallyEq, ae_restrict_iUnion_eq, eventually_iSup]
#align measure_theory.ae_eq_restrict_Union_iff MeasureTheory.ae_eq_restrict_iUnion_iff
theorem ae_eq_restrict_biUnion_iff (s : ι → Set α) {t : Set ι} (ht : t.Countable) (f g : α → δ) :
f =ᵐ[μ.restrict (⋃ i ∈ t, s i)] g ↔ ∀ i ∈ t, f =ᵐ[μ.restrict (s i)] g := by
simp_rw [ae_restrict_biUnion_eq s ht, EventuallyEq, eventually_iSup]
#align measure_theory.ae_eq_restrict_bUnion_iff MeasureTheory.ae_eq_restrict_biUnion_iff
theorem ae_eq_restrict_biUnion_finset_iff (s : ι → Set α) (t : Finset ι) (f g : α → δ) :
f =ᵐ[μ.restrict (⋃ i ∈ t, s i)] g ↔ ∀ i ∈ t, f =ᵐ[μ.restrict (s i)] g :=
ae_eq_restrict_biUnion_iff s t.countable_toSet f g
#align measure_theory.ae_eq_restrict_bUnion_finset_iff MeasureTheory.ae_eq_restrict_biUnion_finset_iff
theorem ae_restrict_uIoc_eq [LinearOrder α] (a b : α) :
ae (μ.restrict (Ι a b)) = ae (μ.restrict (Ioc a b)) ⊔ ae (μ.restrict (Ioc b a)) := by
simp only [uIoc_eq_union, ae_restrict_union_eq]
#align measure_theory.ae_restrict_uIoc_eq MeasureTheory.ae_restrict_uIoc_eq
| Mathlib/MeasureTheory/Measure/Restrict.lean | 608 | 611 | theorem ae_restrict_uIoc_iff [LinearOrder α] {a b : α} {P : α → Prop} :
(∀ᵐ x ∂μ.restrict (Ι a b), P x) ↔
(∀ᵐ x ∂μ.restrict (Ioc a b), P x) ∧ ∀ᵐ x ∂μ.restrict (Ioc b a), P x := by |
rw [ae_restrict_uIoc_eq, eventually_sup]
|
import Mathlib.Algebra.Group.Nat
import Mathlib.Algebra.Order.Sub.Canonical
import Mathlib.Data.List.Perm
import Mathlib.Data.Set.List
import Mathlib.Init.Quot
import Mathlib.Order.Hom.Basic
#align_import data.multiset.basic from "leanprover-community/mathlib"@"65a1391a0106c9204fe45bc73a039f056558cb83"
universe v
open List Subtype Nat Function
variable {α : Type*} {β : Type v} {γ : Type*}
def Multiset.{u} (α : Type u) : Type u :=
Quotient (List.isSetoid α)
#align multiset Multiset
namespace Multiset
-- Porting note: new
@[coe]
def ofList : List α → Multiset α :=
Quot.mk _
instance : Coe (List α) (Multiset α) :=
⟨ofList⟩
@[simp]
theorem quot_mk_to_coe (l : List α) : @Eq (Multiset α) ⟦l⟧ l :=
rfl
#align multiset.quot_mk_to_coe Multiset.quot_mk_to_coe
@[simp]
theorem quot_mk_to_coe' (l : List α) : @Eq (Multiset α) (Quot.mk (· ≈ ·) l) l :=
rfl
#align multiset.quot_mk_to_coe' Multiset.quot_mk_to_coe'
@[simp]
theorem quot_mk_to_coe'' (l : List α) : @Eq (Multiset α) (Quot.mk Setoid.r l) l :=
rfl
#align multiset.quot_mk_to_coe'' Multiset.quot_mk_to_coe''
@[simp]
theorem coe_eq_coe {l₁ l₂ : List α} : (l₁ : Multiset α) = l₂ ↔ l₁ ~ l₂ :=
Quotient.eq
#align multiset.coe_eq_coe Multiset.coe_eq_coe
-- Porting note: new instance;
-- Porting note (#11215): TODO: move to better place
instance [DecidableEq α] (l₁ l₂ : List α) : Decidable (l₁ ≈ l₂) :=
inferInstanceAs (Decidable (l₁ ~ l₂))
-- Porting note: `Quotient.recOnSubsingleton₂ s₁ s₂` was in parens which broke elaboration
instance decidableEq [DecidableEq α] : DecidableEq (Multiset α)
| s₁, s₂ => Quotient.recOnSubsingleton₂ s₁ s₂ fun _ _ => decidable_of_iff' _ Quotient.eq
#align multiset.has_decidable_eq Multiset.decidableEq
protected
def sizeOf [SizeOf α] (s : Multiset α) : ℕ :=
(Quot.liftOn s SizeOf.sizeOf) fun _ _ => Perm.sizeOf_eq_sizeOf
#align multiset.sizeof Multiset.sizeOf
instance [SizeOf α] : SizeOf (Multiset α) :=
⟨Multiset.sizeOf⟩
protected def zero : Multiset α :=
@nil α
#align multiset.zero Multiset.zero
instance : Zero (Multiset α) :=
⟨Multiset.zero⟩
instance : EmptyCollection (Multiset α) :=
⟨0⟩
instance inhabitedMultiset : Inhabited (Multiset α) :=
⟨0⟩
#align multiset.inhabited_multiset Multiset.inhabitedMultiset
instance [IsEmpty α] : Unique (Multiset α) where
default := 0
uniq := by rintro ⟨_ | ⟨a, l⟩⟩; exacts [rfl, isEmptyElim a]
@[simp]
theorem coe_nil : (@nil α : Multiset α) = 0 :=
rfl
#align multiset.coe_nil Multiset.coe_nil
@[simp]
theorem empty_eq_zero : (∅ : Multiset α) = 0 :=
rfl
#align multiset.empty_eq_zero Multiset.empty_eq_zero
@[simp]
theorem coe_eq_zero (l : List α) : (l : Multiset α) = 0 ↔ l = [] :=
Iff.trans coe_eq_coe perm_nil
#align multiset.coe_eq_zero Multiset.coe_eq_zero
theorem coe_eq_zero_iff_isEmpty (l : List α) : (l : Multiset α) = 0 ↔ l.isEmpty :=
Iff.trans (coe_eq_zero l) isEmpty_iff_eq_nil.symm
#align multiset.coe_eq_zero_iff_empty Multiset.coe_eq_zero_iff_isEmpty
def cons (a : α) (s : Multiset α) : Multiset α :=
Quot.liftOn s (fun l => (a :: l : Multiset α)) fun _ _ p => Quot.sound (p.cons a)
#align multiset.cons Multiset.cons
@[inherit_doc Multiset.cons]
infixr:67 " ::ₘ " => Multiset.cons
instance : Insert α (Multiset α) :=
⟨cons⟩
@[simp]
theorem insert_eq_cons (a : α) (s : Multiset α) : insert a s = a ::ₘ s :=
rfl
#align multiset.insert_eq_cons Multiset.insert_eq_cons
@[simp]
theorem cons_coe (a : α) (l : List α) : (a ::ₘ l : Multiset α) = (a :: l : List α) :=
rfl
#align multiset.cons_coe Multiset.cons_coe
@[simp]
theorem cons_inj_left {a b : α} (s : Multiset α) : a ::ₘ s = b ::ₘ s ↔ a = b :=
⟨Quot.inductionOn s fun l e =>
have : [a] ++ l ~ [b] ++ l := Quotient.exact e
singleton_perm_singleton.1 <| (perm_append_right_iff _).1 this,
congr_arg (· ::ₘ _)⟩
#align multiset.cons_inj_left Multiset.cons_inj_left
@[simp]
theorem cons_inj_right (a : α) : ∀ {s t : Multiset α}, a ::ₘ s = a ::ₘ t ↔ s = t := by
rintro ⟨l₁⟩ ⟨l₂⟩; simp
#align multiset.cons_inj_right Multiset.cons_inj_right
@[elab_as_elim]
protected theorem induction {p : Multiset α → Prop} (empty : p 0)
(cons : ∀ (a : α) (s : Multiset α), p s → p (a ::ₘ s)) : ∀ s, p s := by
rintro ⟨l⟩; induction' l with _ _ ih <;> [exact empty; exact cons _ _ ih]
#align multiset.induction Multiset.induction
@[elab_as_elim]
protected theorem induction_on {p : Multiset α → Prop} (s : Multiset α) (empty : p 0)
(cons : ∀ (a : α) (s : Multiset α), p s → p (a ::ₘ s)) : p s :=
Multiset.induction empty cons s
#align multiset.induction_on Multiset.induction_on
theorem cons_swap (a b : α) (s : Multiset α) : a ::ₘ b ::ₘ s = b ::ₘ a ::ₘ s :=
Quot.inductionOn s fun _ => Quotient.sound <| Perm.swap _ _ _
#align multiset.cons_swap Multiset.cons_swap
instance : Singleton α (Multiset α) :=
⟨fun a => a ::ₘ 0⟩
instance : LawfulSingleton α (Multiset α) :=
⟨fun _ => rfl⟩
@[simp]
theorem cons_zero (a : α) : a ::ₘ 0 = {a} :=
rfl
#align multiset.cons_zero Multiset.cons_zero
@[simp, norm_cast]
theorem coe_singleton (a : α) : ([a] : Multiset α) = {a} :=
rfl
#align multiset.coe_singleton Multiset.coe_singleton
@[simp]
theorem mem_singleton {a b : α} : b ∈ ({a} : Multiset α) ↔ b = a := by
simp only [← cons_zero, mem_cons, iff_self_iff, or_false_iff, not_mem_zero]
#align multiset.mem_singleton Multiset.mem_singleton
theorem mem_singleton_self (a : α) : a ∈ ({a} : Multiset α) := by
rw [← cons_zero]
exact mem_cons_self _ _
#align multiset.mem_singleton_self Multiset.mem_singleton_self
@[simp]
theorem singleton_inj {a b : α} : ({a} : Multiset α) = {b} ↔ a = b := by
simp_rw [← cons_zero]
exact cons_inj_left _
#align multiset.singleton_inj Multiset.singleton_inj
@[simp, norm_cast]
theorem coe_eq_singleton {l : List α} {a : α} : (l : Multiset α) = {a} ↔ l = [a] := by
rw [← coe_singleton, coe_eq_coe, List.perm_singleton]
#align multiset.coe_eq_singleton Multiset.coe_eq_singleton
@[simp]
theorem singleton_eq_cons_iff {a b : α} (m : Multiset α) : {a} = b ::ₘ m ↔ a = b ∧ m = 0 := by
rw [← cons_zero, cons_eq_cons]
simp [eq_comm]
#align multiset.singleton_eq_cons_iff Multiset.singleton_eq_cons_iff
theorem pair_comm (x y : α) : ({x, y} : Multiset α) = {y, x} :=
cons_swap x y 0
#align multiset.pair_comm Multiset.pair_comm
protected def Le (s t : Multiset α) : Prop :=
(Quotient.liftOn₂ s t (· <+~ ·)) fun _ _ _ _ p₁ p₂ =>
propext (p₂.subperm_left.trans p₁.subperm_right)
#align multiset.le Multiset.Le
instance : PartialOrder (Multiset α) where
le := Multiset.Le
le_refl := by rintro ⟨l⟩; exact Subperm.refl _
le_trans := by rintro ⟨l₁⟩ ⟨l₂⟩ ⟨l₃⟩; exact @Subperm.trans _ _ _ _
le_antisymm := by rintro ⟨l₁⟩ ⟨l₂⟩ h₁ h₂; exact Quot.sound (Subperm.antisymm h₁ h₂)
instance decidableLE [DecidableEq α] : DecidableRel ((· ≤ ·) : Multiset α → Multiset α → Prop) :=
fun s t => Quotient.recOnSubsingleton₂ s t List.decidableSubperm
#align multiset.decidable_le Multiset.decidableLE
section
variable {s t : Multiset α} {a : α}
theorem subset_of_le : s ≤ t → s ⊆ t :=
Quotient.inductionOn₂ s t fun _ _ => Subperm.subset
#align multiset.subset_of_le Multiset.subset_of_le
alias Le.subset := subset_of_le
#align multiset.le.subset Multiset.Le.subset
theorem mem_of_le (h : s ≤ t) : a ∈ s → a ∈ t :=
mem_of_subset (subset_of_le h)
#align multiset.mem_of_le Multiset.mem_of_le
theorem not_mem_mono (h : s ⊆ t) : a ∉ t → a ∉ s :=
mt <| @h _
#align multiset.not_mem_mono Multiset.not_mem_mono
@[simp]
theorem coe_le {l₁ l₂ : List α} : (l₁ : Multiset α) ≤ l₂ ↔ l₁ <+~ l₂ :=
Iff.rfl
#align multiset.coe_le Multiset.coe_le
@[elab_as_elim]
theorem leInductionOn {C : Multiset α → Multiset α → Prop} {s t : Multiset α} (h : s ≤ t)
(H : ∀ {l₁ l₂ : List α}, l₁ <+ l₂ → C l₁ l₂) : C s t :=
Quotient.inductionOn₂ s t (fun l₁ _ ⟨l, p, s⟩ => (show ⟦l⟧ = ⟦l₁⟧ from Quot.sound p) ▸ H s) h
#align multiset.le_induction_on Multiset.leInductionOn
theorem zero_le (s : Multiset α) : 0 ≤ s :=
Quot.inductionOn s fun l => (nil_sublist l).subperm
#align multiset.zero_le Multiset.zero_le
instance : OrderBot (Multiset α) where
bot := 0
bot_le := zero_le
@[simp]
theorem bot_eq_zero : (⊥ : Multiset α) = 0 :=
rfl
#align multiset.bot_eq_zero Multiset.bot_eq_zero
theorem le_zero : s ≤ 0 ↔ s = 0 :=
le_bot_iff
#align multiset.le_zero Multiset.le_zero
theorem lt_cons_self (s : Multiset α) (a : α) : s < a ::ₘ s :=
Quot.inductionOn s fun l =>
suffices l <+~ a :: l ∧ ¬l ~ a :: l by simpa [lt_iff_le_and_ne]
⟨(sublist_cons _ _).subperm, fun p => _root_.ne_of_lt (lt_succ_self (length l)) p.length_eq⟩
#align multiset.lt_cons_self Multiset.lt_cons_self
theorem le_cons_self (s : Multiset α) (a : α) : s ≤ a ::ₘ s :=
le_of_lt <| lt_cons_self _ _
#align multiset.le_cons_self Multiset.le_cons_self
theorem cons_le_cons_iff (a : α) : a ::ₘ s ≤ a ::ₘ t ↔ s ≤ t :=
Quotient.inductionOn₂ s t fun _ _ => subperm_cons a
#align multiset.cons_le_cons_iff Multiset.cons_le_cons_iff
theorem cons_le_cons (a : α) : s ≤ t → a ::ₘ s ≤ a ::ₘ t :=
(cons_le_cons_iff a).2
#align multiset.cons_le_cons Multiset.cons_le_cons
@[simp] lemma cons_lt_cons_iff : a ::ₘ s < a ::ₘ t ↔ s < t :=
lt_iff_lt_of_le_iff_le' (cons_le_cons_iff _) (cons_le_cons_iff _)
lemma cons_lt_cons (a : α) (h : s < t) : a ::ₘ s < a ::ₘ t := cons_lt_cons_iff.2 h
theorem le_cons_of_not_mem (m : a ∉ s) : s ≤ a ::ₘ t ↔ s ≤ t := by
refine ⟨?_, fun h => le_trans h <| le_cons_self _ _⟩
suffices ∀ {t'}, s ≤ t' → a ∈ t' → a ::ₘ s ≤ t' by
exact fun h => (cons_le_cons_iff a).1 (this h (mem_cons_self _ _))
introv h
revert m
refine leInductionOn h ?_
introv s m₁ m₂
rcases append_of_mem m₂ with ⟨r₁, r₂, rfl⟩
exact
perm_middle.subperm_left.2
((subperm_cons _).2 <| ((sublist_or_mem_of_sublist s).resolve_right m₁).subperm)
#align multiset.le_cons_of_not_mem Multiset.le_cons_of_not_mem
@[simp]
theorem singleton_ne_zero (a : α) : ({a} : Multiset α) ≠ 0 :=
ne_of_gt (lt_cons_self _ _)
#align multiset.singleton_ne_zero Multiset.singleton_ne_zero
@[simp]
theorem singleton_le {a : α} {s : Multiset α} : {a} ≤ s ↔ a ∈ s :=
⟨fun h => mem_of_le h (mem_singleton_self _), fun h =>
let ⟨_t, e⟩ := exists_cons_of_mem h
e.symm ▸ cons_le_cons _ (zero_le _)⟩
#align multiset.singleton_le Multiset.singleton_le
@[simp] lemma le_singleton : s ≤ {a} ↔ s = 0 ∨ s = {a} :=
Quot.induction_on s fun l ↦ by simp only [cons_zero, ← coe_singleton, quot_mk_to_coe'', coe_le,
coe_eq_zero, coe_eq_coe, perm_singleton, subperm_singleton_iff]
@[simp] lemma lt_singleton : s < {a} ↔ s = 0 := by
simp only [lt_iff_le_and_ne, le_singleton, or_and_right, Ne, and_not_self, or_false,
and_iff_left_iff_imp]
rintro rfl
exact (singleton_ne_zero _).symm
@[simp] lemma ssubset_singleton_iff : s ⊂ {a} ↔ s = 0 := by
refine ⟨fun hs ↦ eq_zero_of_subset_zero fun b hb ↦ (hs.2 ?_).elim, ?_⟩
· obtain rfl := mem_singleton.1 (hs.1 hb)
rwa [singleton_subset]
· rintro rfl
simp
end
protected def add (s₁ s₂ : Multiset α) : Multiset α :=
(Quotient.liftOn₂ s₁ s₂ fun l₁ l₂ => ((l₁ ++ l₂ : List α) : Multiset α)) fun _ _ _ _ p₁ p₂ =>
Quot.sound <| p₁.append p₂
#align multiset.add Multiset.add
instance : Add (Multiset α) :=
⟨Multiset.add⟩
@[simp]
theorem coe_add (s t : List α) : (s + t : Multiset α) = (s ++ t : List α) :=
rfl
#align multiset.coe_add Multiset.coe_add
@[simp]
theorem singleton_add (a : α) (s : Multiset α) : {a} + s = a ::ₘ s :=
rfl
#align multiset.singleton_add Multiset.singleton_add
private theorem add_le_add_iff_left' {s t u : Multiset α} : s + t ≤ s + u ↔ t ≤ u :=
Quotient.inductionOn₃ s t u fun _ _ _ => subperm_append_left _
instance : CovariantClass (Multiset α) (Multiset α) (· + ·) (· ≤ ·) :=
⟨fun _s _t _u => add_le_add_iff_left'.2⟩
instance : ContravariantClass (Multiset α) (Multiset α) (· + ·) (· ≤ ·) :=
⟨fun _s _t _u => add_le_add_iff_left'.1⟩
instance : OrderedCancelAddCommMonoid (Multiset α) where
zero := 0
add := (· + ·)
add_comm := fun s t => Quotient.inductionOn₂ s t fun l₁ l₂ => Quot.sound perm_append_comm
add_assoc := fun s₁ s₂ s₃ =>
Quotient.inductionOn₃ s₁ s₂ s₃ fun l₁ l₂ l₃ => congr_arg _ <| append_assoc l₁ l₂ l₃
zero_add := fun s => Quot.inductionOn s fun l => rfl
add_zero := fun s => Quotient.inductionOn s fun l => congr_arg _ <| append_nil l
add_le_add_left := fun s₁ s₂ => add_le_add_left
le_of_add_le_add_left := fun s₁ s₂ s₃ => le_of_add_le_add_left
nsmul := nsmulRec
theorem le_add_right (s t : Multiset α) : s ≤ s + t := by simpa using add_le_add_left (zero_le t) s
#align multiset.le_add_right Multiset.le_add_right
theorem le_add_left (s t : Multiset α) : s ≤ t + s := by simpa using add_le_add_right (zero_le t) s
#align multiset.le_add_left Multiset.le_add_left
theorem le_iff_exists_add {s t : Multiset α} : s ≤ t ↔ ∃ u, t = s + u :=
⟨fun h =>
leInductionOn h fun s =>
let ⟨l, p⟩ := s.exists_perm_append
⟨l, Quot.sound p⟩,
fun ⟨_u, e⟩ => e.symm ▸ le_add_right _ _⟩
#align multiset.le_iff_exists_add Multiset.le_iff_exists_add
instance : CanonicallyOrderedAddCommMonoid (Multiset α) where
__ := inferInstanceAs (OrderBot (Multiset α))
le_self_add := le_add_right
exists_add_of_le h := leInductionOn h fun s =>
let ⟨l, p⟩ := s.exists_perm_append
⟨l, Quot.sound p⟩
@[simp]
theorem cons_add (a : α) (s t : Multiset α) : a ::ₘ s + t = a ::ₘ (s + t) := by
rw [← singleton_add, ← singleton_add, add_assoc]
#align multiset.cons_add Multiset.cons_add
@[simp]
theorem add_cons (a : α) (s t : Multiset α) : s + a ::ₘ t = a ::ₘ (s + t) := by
rw [add_comm, cons_add, add_comm]
#align multiset.add_cons Multiset.add_cons
@[simp]
theorem mem_add {a : α} {s t : Multiset α} : a ∈ s + t ↔ a ∈ s ∨ a ∈ t :=
Quotient.inductionOn₂ s t fun _l₁ _l₂ => mem_append
#align multiset.mem_add Multiset.mem_add
theorem mem_of_mem_nsmul {a : α} {s : Multiset α} {n : ℕ} (h : a ∈ n • s) : a ∈ s := by
induction' n with n ih
· rw [zero_nsmul] at h
exact absurd h (not_mem_zero _)
· rw [succ_nsmul, mem_add] at h
exact h.elim ih id
#align multiset.mem_of_mem_nsmul Multiset.mem_of_mem_nsmul
@[simp]
theorem mem_nsmul {a : α} {s : Multiset α} {n : ℕ} (h0 : n ≠ 0) : a ∈ n • s ↔ a ∈ s := by
refine ⟨mem_of_mem_nsmul, fun h => ?_⟩
obtain ⟨n, rfl⟩ := exists_eq_succ_of_ne_zero h0
rw [succ_nsmul, mem_add]
exact Or.inr h
#align multiset.mem_nsmul Multiset.mem_nsmul
theorem nsmul_cons {s : Multiset α} (n : ℕ) (a : α) :
n • (a ::ₘ s) = n • ({a} : Multiset α) + n • s := by
rw [← singleton_add, nsmul_add]
#align multiset.nsmul_cons Multiset.nsmul_cons
def card : Multiset α →+ ℕ where
toFun s := (Quot.liftOn s length) fun _l₁ _l₂ => Perm.length_eq
map_zero' := rfl
map_add' s t := Quotient.inductionOn₂ s t length_append
#align multiset.card Multiset.card
@[simp]
theorem coe_card (l : List α) : card (l : Multiset α) = length l :=
rfl
#align multiset.coe_card Multiset.coe_card
@[simp]
theorem length_toList (s : Multiset α) : s.toList.length = card s := by
rw [← coe_card, coe_toList]
#align multiset.length_to_list Multiset.length_toList
@[simp, nolint simpNF] -- Porting note (#10675): `dsimp` can not prove this, yet linter complains
theorem card_zero : @card α 0 = 0 :=
rfl
#align multiset.card_zero Multiset.card_zero
theorem card_add (s t : Multiset α) : card (s + t) = card s + card t :=
card.map_add s t
#align multiset.card_add Multiset.card_add
theorem card_nsmul (s : Multiset α) (n : ℕ) : card (n • s) = n * card s := by
rw [card.map_nsmul s n, Nat.nsmul_eq_mul]
#align multiset.card_nsmul Multiset.card_nsmul
@[simp]
theorem card_cons (a : α) (s : Multiset α) : card (a ::ₘ s) = card s + 1 :=
Quot.inductionOn s fun _l => rfl
#align multiset.card_cons Multiset.card_cons
@[simp]
theorem card_singleton (a : α) : card ({a} : Multiset α) = 1 := by
simp only [← cons_zero, card_zero, eq_self_iff_true, zero_add, card_cons]
#align multiset.card_singleton Multiset.card_singleton
theorem card_pair (a b : α) : card {a, b} = 2 := by
rw [insert_eq_cons, card_cons, card_singleton]
#align multiset.card_pair Multiset.card_pair
theorem card_eq_one {s : Multiset α} : card s = 1 ↔ ∃ a, s = {a} :=
⟨Quot.inductionOn s fun _l h => (List.length_eq_one.1 h).imp fun _a => congr_arg _,
fun ⟨_a, e⟩ => e.symm ▸ rfl⟩
#align multiset.card_eq_one Multiset.card_eq_one
theorem card_le_card {s t : Multiset α} (h : s ≤ t) : card s ≤ card t :=
leInductionOn h Sublist.length_le
#align multiset.card_le_of_le Multiset.card_le_card
@[mono]
theorem card_mono : Monotone (@card α) := fun _a _b => card_le_card
#align multiset.card_mono Multiset.card_mono
theorem eq_of_le_of_card_le {s t : Multiset α} (h : s ≤ t) : card t ≤ card s → s = t :=
leInductionOn h fun s h₂ => congr_arg _ <| s.eq_of_length_le h₂
#align multiset.eq_of_le_of_card_le Multiset.eq_of_le_of_card_le
theorem card_lt_card {s t : Multiset α} (h : s < t) : card s < card t :=
lt_of_not_ge fun h₂ => _root_.ne_of_lt h <| eq_of_le_of_card_le (le_of_lt h) h₂
#align multiset.card_lt_card Multiset.card_lt_card
lemma card_strictMono : StrictMono (card : Multiset α → ℕ) := fun _ _ ↦ card_lt_card
theorem lt_iff_cons_le {s t : Multiset α} : s < t ↔ ∃ a, a ::ₘ s ≤ t :=
⟨Quotient.inductionOn₂ s t fun _l₁ _l₂ h =>
Subperm.exists_of_length_lt (le_of_lt h) (card_lt_card h),
fun ⟨_a, h⟩ => lt_of_lt_of_le (lt_cons_self _ _) h⟩
#align multiset.lt_iff_cons_le Multiset.lt_iff_cons_le
@[simp]
theorem card_eq_zero {s : Multiset α} : card s = 0 ↔ s = 0 :=
⟨fun h => (eq_of_le_of_card_le (zero_le _) (le_of_eq h)).symm, fun e => by simp [e]⟩
#align multiset.card_eq_zero Multiset.card_eq_zero
theorem card_pos {s : Multiset α} : 0 < card s ↔ s ≠ 0 :=
Nat.pos_iff_ne_zero.trans <| not_congr card_eq_zero
#align multiset.card_pos Multiset.card_pos
theorem card_pos_iff_exists_mem {s : Multiset α} : 0 < card s ↔ ∃ a, a ∈ s :=
Quot.inductionOn s fun _l => length_pos_iff_exists_mem
#align multiset.card_pos_iff_exists_mem Multiset.card_pos_iff_exists_mem
theorem card_eq_two {s : Multiset α} : card s = 2 ↔ ∃ x y, s = {x, y} :=
⟨Quot.inductionOn s fun _l h =>
(List.length_eq_two.mp h).imp fun _a => Exists.imp fun _b => congr_arg _,
fun ⟨_a, _b, e⟩ => e.symm ▸ rfl⟩
#align multiset.card_eq_two Multiset.card_eq_two
theorem card_eq_three {s : Multiset α} : card s = 3 ↔ ∃ x y z, s = {x, y, z} :=
⟨Quot.inductionOn s fun _l h =>
(List.length_eq_three.mp h).imp fun _a =>
Exists.imp fun _b => Exists.imp fun _c => congr_arg _,
fun ⟨_a, _b, _c, e⟩ => e.symm ▸ rfl⟩
#align multiset.card_eq_three Multiset.card_eq_three
@[elab_as_elim]
def strongInductionOn {p : Multiset α → Sort*} (s : Multiset α) (ih : ∀ s, (∀ t < s, p t) → p s) :
p s :=
(ih s) fun t _h =>
strongInductionOn t ih
termination_by card s
decreasing_by exact card_lt_card _h
#align multiset.strong_induction_on Multiset.strongInductionOnₓ -- Porting note: reorderd universes
| Mathlib/Data/Multiset/Basic.lean | 862 | 864 | theorem strongInductionOn_eq {p : Multiset α → Sort*} (s : Multiset α) (H) :
@strongInductionOn _ p s H = H s fun t _h => @strongInductionOn _ p t H := by |
rw [strongInductionOn]
|
import Mathlib.Algebra.Homology.Additive
import Mathlib.CategoryTheory.Abelian.Pseudoelements
import Mathlib.CategoryTheory.Limits.Preserves.Shapes.Kernels
import Mathlib.CategoryTheory.Limits.Preserves.Shapes.Images
#align_import category_theory.abelian.homology from "leanprover-community/mathlib"@"956af7c76589f444f2e1313911bad16366ea476d"
open CategoryTheory.Limits
open CategoryTheory
noncomputable section
universe v u
variable {A : Type u} [Category.{v} A] [Abelian A]
variable {X Y Z : A} (f : X ⟶ Y) (g : Y ⟶ Z) (w : f ≫ g = 0)
def homology'IsoKernelDesc : homology' f g w ≅ kernel (cokernel.desc f g w) :=
homology'IsoCokernelLift _ _ _ ≪≫ asIso (CategoryTheory.Abelian.homologyCToK _ _ _)
#align homology_iso_kernel_desc homology'IsoKernelDesc
namespace homology'
-- `homology'.π` is taken
def π' : kernel g ⟶ homology' f g w :=
cokernel.π _ ≫ (homology'IsoCokernelLift _ _ _).inv
#align homology.π' homology'.π'
def ι : homology' f g w ⟶ cokernel f :=
(homology'IsoKernelDesc _ _ _).hom ≫ kernel.ι _
#align homology.ι homology'.ι
def desc' {W : A} (e : kernel g ⟶ W) (he : kernel.lift g f w ≫ e = 0) : homology' f g w ⟶ W :=
(homology'IsoCokernelLift _ _ _).hom ≫ cokernel.desc _ e he
#align homology.desc' homology'.desc'
def lift {W : A} (e : W ⟶ cokernel f) (he : e ≫ cokernel.desc f g w = 0) : W ⟶ homology' f g w :=
kernel.lift _ e he ≫ (homology'IsoKernelDesc _ _ _).inv
#align homology.lift homology'.lift
@[reassoc (attr := simp)]
| Mathlib/CategoryTheory/Abelian/Homology.lean | 137 | 140 | theorem π'_desc' {W : A} (e : kernel g ⟶ W) (he : kernel.lift g f w ≫ e = 0) :
π' f g w ≫ desc' f g w e he = e := by |
dsimp [π', desc']
simp
|
import Mathlib.Algebra.ContinuedFractions.Computation.Basic
import Mathlib.Algebra.ContinuedFractions.Translations
#align_import algebra.continued_fractions.computation.translations from "leanprover-community/mathlib"@"a7e36e48519ab281320c4d192da6a7b348ce40ad"
namespace GeneralizedContinuedFraction
open GeneralizedContinuedFraction (of)
-- Fix a discrete linear ordered floor field and a value `v`.
variable {K : Type*} [LinearOrderedField K] [FloorRing K] {v : K}
section sequence
variable {n : ℕ}
theorem IntFractPair.get?_seq1_eq_succ_get?_stream :
(IntFractPair.seq1 v).snd.get? n = (IntFractPair.stream v) (n + 1) :=
rfl
#align generalized_continued_fraction.int_fract_pair.nth_seq1_eq_succ_nth_stream GeneralizedContinuedFraction.IntFractPair.get?_seq1_eq_succ_get?_stream
section Termination
theorem of_terminatedAt_iff_intFractPair_seq1_terminatedAt :
(of v).TerminatedAt n ↔ (IntFractPair.seq1 v).snd.TerminatedAt n :=
Option.map_eq_none
#align generalized_continued_fraction.of_terminated_at_iff_int_fract_pair_seq1_terminated_at GeneralizedContinuedFraction.of_terminatedAt_iff_intFractPair_seq1_terminatedAt
| Mathlib/Algebra/ContinuedFractions/Computation/Translations.lean | 209 | 212 | theorem of_terminatedAt_n_iff_succ_nth_intFractPair_stream_eq_none :
(of v).TerminatedAt n ↔ IntFractPair.stream v (n + 1) = none := by |
rw [of_terminatedAt_iff_intFractPair_seq1_terminatedAt, Stream'.Seq.TerminatedAt,
IntFractPair.get?_seq1_eq_succ_get?_stream]
|
import Mathlib.AlgebraicTopology.SimplexCategory
import Mathlib.CategoryTheory.Comma.Arrow
import Mathlib.CategoryTheory.Limits.FunctorCategory
import Mathlib.CategoryTheory.Opposites
#align_import algebraic_topology.simplicial_object from "leanprover-community/mathlib"@"5ed51dc37c6b891b79314ee11a50adc2b1df6fd6"
open Opposite
open CategoryTheory
open CategoryTheory.Limits
universe v u v' u'
namespace CategoryTheory
variable (C : Type u) [Category.{v} C]
-- porting note (#5171): removed @[nolint has_nonempty_instance]
def SimplicialObject :=
SimplexCategoryᵒᵖ ⥤ C
#align category_theory.simplicial_object CategoryTheory.SimplicialObject
@[simps!]
instance : Category (SimplicialObject C) := by
dsimp only [SimplicialObject]
infer_instance
namespace SimplicialObject
set_option quotPrecheck false in
scoped[Simplicial]
notation3:1000 X " _[" n "]" =>
(X : CategoryTheory.SimplicialObject _).obj (Opposite.op (SimplexCategory.mk n))
open Simplicial
instance {J : Type v} [SmallCategory J] [HasLimitsOfShape J C] :
HasLimitsOfShape J (SimplicialObject C) := by
dsimp [SimplicialObject]
infer_instance
instance [HasLimits C] : HasLimits (SimplicialObject C) :=
⟨inferInstance⟩
instance {J : Type v} [SmallCategory J] [HasColimitsOfShape J C] :
HasColimitsOfShape J (SimplicialObject C) := by
dsimp [SimplicialObject]
infer_instance
instance [HasColimits C] : HasColimits (SimplicialObject C) :=
⟨inferInstance⟩
variable {C}
-- Porting note (#10688): added to ease automation
@[ext]
lemma hom_ext {X Y : SimplicialObject C} (f g : X ⟶ Y)
(h : ∀ (n : SimplexCategoryᵒᵖ), f.app n = g.app n) : f = g :=
NatTrans.ext _ _ (by ext; apply h)
variable (X : SimplicialObject C)
def δ {n} (i : Fin (n + 2)) : X _[n + 1] ⟶ X _[n] :=
X.map (SimplexCategory.δ i).op
#align category_theory.simplicial_object.δ CategoryTheory.SimplicialObject.δ
def σ {n} (i : Fin (n + 1)) : X _[n] ⟶ X _[n + 1] :=
X.map (SimplexCategory.σ i).op
#align category_theory.simplicial_object.σ CategoryTheory.SimplicialObject.σ
def eqToIso {n m : ℕ} (h : n = m) : X _[n] ≅ X _[m] :=
X.mapIso (CategoryTheory.eqToIso (by congr))
#align category_theory.simplicial_object.eq_to_iso CategoryTheory.SimplicialObject.eqToIso
@[simp]
theorem eqToIso_refl {n : ℕ} (h : n = n) : X.eqToIso h = Iso.refl _ := by
ext
simp [eqToIso]
#align category_theory.simplicial_object.eq_to_iso_refl CategoryTheory.SimplicialObject.eqToIso_refl
@[reassoc]
theorem δ_comp_δ {n} {i j : Fin (n + 2)} (H : i ≤ j) :
X.δ j.succ ≫ X.δ i = X.δ (Fin.castSucc i) ≫ X.δ j := by
dsimp [δ]
simp only [← X.map_comp, ← op_comp, SimplexCategory.δ_comp_δ H]
#align category_theory.simplicial_object.δ_comp_δ CategoryTheory.SimplicialObject.δ_comp_δ
@[reassoc]
theorem δ_comp_δ' {n} {i : Fin (n + 2)} {j : Fin (n + 3)} (H : Fin.castSucc i < j) :
X.δ j ≫ X.δ i =
X.δ (Fin.castSucc i) ≫
X.δ (j.pred fun (hj : j = 0) => by simp [hj, Fin.not_lt_zero] at H) := by
dsimp [δ]
simp only [← X.map_comp, ← op_comp, SimplexCategory.δ_comp_δ' H]
#align category_theory.simplicial_object.δ_comp_δ' CategoryTheory.SimplicialObject.δ_comp_δ'
@[reassoc]
theorem δ_comp_δ'' {n} {i : Fin (n + 3)} {j : Fin (n + 2)} (H : i ≤ Fin.castSucc j) :
X.δ j.succ ≫ X.δ (i.castLT (Nat.lt_of_le_of_lt (Fin.le_iff_val_le_val.mp H) j.is_lt)) =
X.δ i ≫ X.δ j := by
dsimp [δ]
simp only [← X.map_comp, ← op_comp, SimplexCategory.δ_comp_δ'' H]
#align category_theory.simplicial_object.δ_comp_δ'' CategoryTheory.SimplicialObject.δ_comp_δ''
@[reassoc]
| Mathlib/AlgebraicTopology/SimplicialObject.lean | 131 | 134 | theorem δ_comp_δ_self {n} {i : Fin (n + 2)} :
X.δ (Fin.castSucc i) ≫ X.δ i = X.δ i.succ ≫ X.δ i := by |
dsimp [δ]
simp only [← X.map_comp, ← op_comp, SimplexCategory.δ_comp_δ_self]
|
import Mathlib.Algebra.CharP.ExpChar
import Mathlib.Algebra.GeomSum
import Mathlib.Algebra.MvPolynomial.CommRing
import Mathlib.Algebra.MvPolynomial.Equiv
import Mathlib.RingTheory.Polynomial.Content
import Mathlib.RingTheory.UniqueFactorizationDomain
#align_import ring_theory.polynomial.basic from "leanprover-community/mathlib"@"da420a8c6dd5bdfb85c4ced85c34388f633bc6ff"
noncomputable section
open Polynomial
open Finset
universe u v w
variable {R : Type u} {S : Type*}
namespace Polynomial
section Semiring
variable [Semiring R]
instance instCharP (p : ℕ) [h : CharP R p] : CharP R[X] p :=
let ⟨h⟩ := h
⟨fun n => by rw [← map_natCast C, ← C_0, C_inj, h]⟩
instance instExpChar (p : ℕ) [h : ExpChar R p] : ExpChar R[X] p := by
cases h; exacts [ExpChar.zero, ExpChar.prime ‹_›]
variable (R)
def degreeLE (n : WithBot ℕ) : Submodule R R[X] :=
⨅ k : ℕ, ⨅ _ : ↑k > n, LinearMap.ker (lcoeff R k)
#align polynomial.degree_le Polynomial.degreeLE
def degreeLT (n : ℕ) : Submodule R R[X] :=
⨅ k : ℕ, ⨅ (_ : k ≥ n), LinearMap.ker (lcoeff R k)
#align polynomial.degree_lt Polynomial.degreeLT
variable {R}
theorem mem_degreeLE {n : WithBot ℕ} {f : R[X]} : f ∈ degreeLE R n ↔ degree f ≤ n := by
simp only [degreeLE, Submodule.mem_iInf, degree_le_iff_coeff_zero, LinearMap.mem_ker]; rfl
#align polynomial.mem_degree_le Polynomial.mem_degreeLE
@[mono]
theorem degreeLE_mono {m n : WithBot ℕ} (H : m ≤ n) : degreeLE R m ≤ degreeLE R n := fun _ hf =>
mem_degreeLE.2 (le_trans (mem_degreeLE.1 hf) H)
#align polynomial.degree_le_mono Polynomial.degreeLE_mono
theorem degreeLE_eq_span_X_pow [DecidableEq R] {n : ℕ} :
degreeLE R n = Submodule.span R ↑((Finset.range (n + 1)).image fun n => (X : R[X]) ^ n) := by
apply le_antisymm
· intro p hp
replace hp := mem_degreeLE.1 hp
rw [← Polynomial.sum_monomial_eq p, Polynomial.sum]
refine Submodule.sum_mem _ fun k hk => ?_
have := WithBot.coe_le_coe.1 (Finset.sup_le_iff.1 hp k hk)
rw [← C_mul_X_pow_eq_monomial, C_mul']
refine
Submodule.smul_mem _ _
(Submodule.subset_span <|
Finset.mem_coe.2 <|
Finset.mem_image.2 ⟨_, Finset.mem_range.2 (Nat.lt_succ_of_le this), rfl⟩)
rw [Submodule.span_le, Finset.coe_image, Set.image_subset_iff]
intro k hk
apply mem_degreeLE.2
exact
(degree_X_pow_le _).trans (WithBot.coe_le_coe.2 <| Nat.le_of_lt_succ <| Finset.mem_range.1 hk)
set_option linter.uppercaseLean3 false in
#align polynomial.degree_le_eq_span_X_pow Polynomial.degreeLE_eq_span_X_pow
theorem mem_degreeLT {n : ℕ} {f : R[X]} : f ∈ degreeLT R n ↔ degree f < n := by
rw [degreeLT, Submodule.mem_iInf]
conv_lhs => intro i; rw [Submodule.mem_iInf]
rw [degree, Finset.max_eq_sup_coe]
rw [Finset.sup_lt_iff ?_]
rotate_left
· apply WithBot.bot_lt_coe
conv_rhs =>
simp only [mem_support_iff]
intro b
rw [Nat.cast_withBot, WithBot.coe_lt_coe, lt_iff_not_le, Ne, not_imp_not]
rfl
#align polynomial.mem_degree_lt Polynomial.mem_degreeLT
@[mono]
theorem degreeLT_mono {m n : ℕ} (H : m ≤ n) : degreeLT R m ≤ degreeLT R n := fun _ hf =>
mem_degreeLT.2 (lt_of_lt_of_le (mem_degreeLT.1 hf) <| WithBot.coe_le_coe.2 H)
#align polynomial.degree_lt_mono Polynomial.degreeLT_mono
theorem degreeLT_eq_span_X_pow [DecidableEq R] {n : ℕ} :
degreeLT R n = Submodule.span R ↑((Finset.range n).image fun n => X ^ n : Finset R[X]) := by
apply le_antisymm
· intro p hp
replace hp := mem_degreeLT.1 hp
rw [← Polynomial.sum_monomial_eq p, Polynomial.sum]
refine Submodule.sum_mem _ fun k hk => ?_
have := WithBot.coe_lt_coe.1 ((Finset.sup_lt_iff <| WithBot.bot_lt_coe n).1 hp k hk)
rw [← C_mul_X_pow_eq_monomial, C_mul']
refine
Submodule.smul_mem _ _
(Submodule.subset_span <|
Finset.mem_coe.2 <| Finset.mem_image.2 ⟨_, Finset.mem_range.2 this, rfl⟩)
rw [Submodule.span_le, Finset.coe_image, Set.image_subset_iff]
intro k hk
apply mem_degreeLT.2
exact lt_of_le_of_lt (degree_X_pow_le _) (WithBot.coe_lt_coe.2 <| Finset.mem_range.1 hk)
set_option linter.uppercaseLean3 false in
#align polynomial.degree_lt_eq_span_X_pow Polynomial.degreeLT_eq_span_X_pow
def degreeLTEquiv (R) [Semiring R] (n : ℕ) : degreeLT R n ≃ₗ[R] Fin n → R where
toFun p n := (↑p : R[X]).coeff n
invFun f :=
⟨∑ i : Fin n, monomial i (f i),
(degreeLT R n).sum_mem fun i _ =>
mem_degreeLT.mpr
(lt_of_le_of_lt (degree_monomial_le i (f i)) (WithBot.coe_lt_coe.mpr i.is_lt))⟩
map_add' p q := by
ext
dsimp
rw [coeff_add]
map_smul' x p := by
ext
dsimp
rw [coeff_smul]
rfl
left_inv := by
rintro ⟨p, hp⟩
ext1
simp only [Submodule.coe_mk]
by_cases hp0 : p = 0
· subst hp0
simp only [coeff_zero, LinearMap.map_zero, Finset.sum_const_zero]
rw [mem_degreeLT, degree_eq_natDegree hp0, Nat.cast_lt] at hp
conv_rhs => rw [p.as_sum_range' n hp, ← Fin.sum_univ_eq_sum_range]
right_inv f := by
ext i
simp only [finset_sum_coeff, Submodule.coe_mk]
rw [Finset.sum_eq_single i, coeff_monomial, if_pos rfl]
· rintro j - hji
rw [coeff_monomial, if_neg]
rwa [← Fin.ext_iff]
· intro h
exact (h (Finset.mem_univ _)).elim
#align polynomial.degree_lt_equiv Polynomial.degreeLTEquiv
-- Porting note: removed @[simp] as simp can prove this
theorem degreeLTEquiv_eq_zero_iff_eq_zero {n : ℕ} {p : R[X]} (hp : p ∈ degreeLT R n) :
degreeLTEquiv _ _ ⟨p, hp⟩ = 0 ↔ p = 0 := by
rw [LinearEquiv.map_eq_zero_iff, Submodule.mk_eq_zero]
#align polynomial.degree_lt_equiv_eq_zero_iff_eq_zero Polynomial.degreeLTEquiv_eq_zero_iff_eq_zero
theorem eval_eq_sum_degreeLTEquiv {n : ℕ} {p : R[X]} (hp : p ∈ degreeLT R n) (x : R) :
p.eval x = ∑ i, degreeLTEquiv _ _ ⟨p, hp⟩ i * x ^ (i : ℕ) := by
simp_rw [eval_eq_sum]
exact (sum_fin _ (by simp_rw [zero_mul, forall_const]) (mem_degreeLT.mp hp)).symm
#align polynomial.eval_eq_sum_degree_lt_equiv Polynomial.eval_eq_sum_degreeLTEquiv
theorem degreeLT_succ_eq_degreeLE {n : ℕ} : degreeLT R (n + 1) = degreeLE R n := by
ext x
by_cases x_zero : x = 0
· simp_rw [x_zero, Submodule.zero_mem]
· rw [mem_degreeLT, mem_degreeLE, ← natDegree_lt_iff_degree_lt (by rwa [ne_eq]),
← natDegree_le_iff_degree_le, Nat.lt_succ]
theorem exists_degree_le_of_mem_span {s : Set R[X]} {p : R[X]}
(hs : s.Nonempty) (hp : p ∈ Submodule.span R s) :
∃ p' ∈ s, degree p ≤ degree p' := by
by_contra! h
by_cases hp_zero : p = 0
· rw [hp_zero, degree_zero] at h
rcases hs with ⟨x, hx⟩
exact not_lt_bot (h x hx)
· have : p ∈ degreeLT R (natDegree p) := by
refine (Submodule.span_le.mpr fun p' p'_mem => ?_) hp
rw [SetLike.mem_coe, mem_degreeLT, Nat.cast_withBot]
exact lt_of_lt_of_le (h p' p'_mem) degree_le_natDegree
rwa [mem_degreeLT, Nat.cast_withBot, degree_eq_natDegree hp_zero,
Nat.cast_withBot, lt_self_iff_false] at this
theorem exists_degree_le_of_mem_span_of_finite {s : Set R[X]} (s_fin : s.Finite) (hs : s.Nonempty) :
∃ p' ∈ s, ∀ (p : R[X]), p ∈ Submodule.span R s → degree p ≤ degree p' := by
rcases Set.Finite.exists_maximal_wrt degree s s_fin hs with ⟨a, has, hmax⟩
refine ⟨a, has, fun p hp => ?_⟩
rcases exists_degree_le_of_mem_span hs hp with ⟨p', hp'⟩
by_cases h : degree a ≤ degree p'
· rw [← hmax p' hp'.left h] at hp'; exact hp'.right
· exact le_trans hp'.right (not_le.mp h).le
theorem span_le_degreeLE_of_finite {s : Set R[X]} (s_fin : s.Finite) :
∃ n : ℕ, Submodule.span R s ≤ degreeLE R n := by
by_cases s_emp : s.Nonempty
· rcases exists_degree_le_of_mem_span_of_finite s_fin s_emp with ⟨p', _, hp'max⟩
exact ⟨natDegree p', fun p hp => mem_degreeLE.mpr ((hp'max _ hp).trans degree_le_natDegree)⟩
· rw [Set.not_nonempty_iff_eq_empty] at s_emp
rw [s_emp, Submodule.span_empty]
exact ⟨0, bot_le⟩
| Mathlib/RingTheory/Polynomial/Basic.lean | 233 | 236 | theorem span_of_finite_le_degreeLT {s : Set R[X]} (s_fin : s.Finite) :
∃ n : ℕ, Submodule.span R s ≤ degreeLT R n := by |
rcases span_le_degreeLE_of_finite s_fin with ⟨n, _⟩
exact ⟨n + 1, by rwa [degreeLT_succ_eq_degreeLE]⟩
|
import Mathlib.Analysis.SpecialFunctions.Exp
import Mathlib.Data.Nat.Factorization.Basic
import Mathlib.Analysis.NormedSpace.Real
#align_import analysis.special_functions.log.basic from "leanprover-community/mathlib"@"f23a09ce6d3f367220dc3cecad6b7eb69eb01690"
open Set Filter Function
open Topology
noncomputable section
namespace Real
variable {x y : ℝ}
-- @[pp_nodot] -- Porting note: removed
noncomputable def log (x : ℝ) : ℝ :=
if hx : x = 0 then 0 else expOrderIso.symm ⟨|x|, abs_pos.2 hx⟩
#align real.log Real.log
theorem log_of_ne_zero (hx : x ≠ 0) : log x = expOrderIso.symm ⟨|x|, abs_pos.2 hx⟩ :=
dif_neg hx
#align real.log_of_ne_zero Real.log_of_ne_zero
theorem log_of_pos (hx : 0 < x) : log x = expOrderIso.symm ⟨x, hx⟩ := by
rw [log_of_ne_zero hx.ne']
congr
exact abs_of_pos hx
#align real.log_of_pos Real.log_of_pos
theorem exp_log_eq_abs (hx : x ≠ 0) : exp (log x) = |x| := by
rw [log_of_ne_zero hx, ← coe_expOrderIso_apply, OrderIso.apply_symm_apply, Subtype.coe_mk]
#align real.exp_log_eq_abs Real.exp_log_eq_abs
theorem exp_log (hx : 0 < x) : exp (log x) = x := by
rw [exp_log_eq_abs hx.ne']
exact abs_of_pos hx
#align real.exp_log Real.exp_log
theorem exp_log_of_neg (hx : x < 0) : exp (log x) = -x := by
rw [exp_log_eq_abs (ne_of_lt hx)]
exact abs_of_neg hx
#align real.exp_log_of_neg Real.exp_log_of_neg
theorem le_exp_log (x : ℝ) : x ≤ exp (log x) := by
by_cases h_zero : x = 0
· rw [h_zero, log, dif_pos rfl, exp_zero]
exact zero_le_one
· rw [exp_log_eq_abs h_zero]
exact le_abs_self _
#align real.le_exp_log Real.le_exp_log
@[simp]
theorem log_exp (x : ℝ) : log (exp x) = x :=
exp_injective <| exp_log (exp_pos x)
#align real.log_exp Real.log_exp
theorem surjOn_log : SurjOn log (Ioi 0) univ := fun x _ => ⟨exp x, exp_pos x, log_exp x⟩
#align real.surj_on_log Real.surjOn_log
theorem log_surjective : Surjective log := fun x => ⟨exp x, log_exp x⟩
#align real.log_surjective Real.log_surjective
@[simp]
theorem range_log : range log = univ :=
log_surjective.range_eq
#align real.range_log Real.range_log
@[simp]
theorem log_zero : log 0 = 0 :=
dif_pos rfl
#align real.log_zero Real.log_zero
@[simp]
theorem log_one : log 1 = 0 :=
exp_injective <| by rw [exp_log zero_lt_one, exp_zero]
#align real.log_one Real.log_one
@[simp]
theorem log_abs (x : ℝ) : log |x| = log x := by
by_cases h : x = 0
· simp [h]
· rw [← exp_eq_exp, exp_log_eq_abs h, exp_log_eq_abs (abs_pos.2 h).ne', abs_abs]
#align real.log_abs Real.log_abs
@[simp]
theorem log_neg_eq_log (x : ℝ) : log (-x) = log x := by rw [← log_abs x, ← log_abs (-x), abs_neg]
#align real.log_neg_eq_log Real.log_neg_eq_log
theorem sinh_log {x : ℝ} (hx : 0 < x) : sinh (log x) = (x - x⁻¹) / 2 := by
rw [sinh_eq, exp_neg, exp_log hx]
#align real.sinh_log Real.sinh_log
theorem cosh_log {x : ℝ} (hx : 0 < x) : cosh (log x) = (x + x⁻¹) / 2 := by
rw [cosh_eq, exp_neg, exp_log hx]
#align real.cosh_log Real.cosh_log
theorem surjOn_log' : SurjOn log (Iio 0) univ := fun x _ =>
⟨-exp x, neg_lt_zero.2 <| exp_pos x, by rw [log_neg_eq_log, log_exp]⟩
#align real.surj_on_log' Real.surjOn_log'
theorem log_mul (hx : x ≠ 0) (hy : y ≠ 0) : log (x * y) = log x + log y :=
exp_injective <| by
rw [exp_log_eq_abs (mul_ne_zero hx hy), exp_add, exp_log_eq_abs hx, exp_log_eq_abs hy, abs_mul]
#align real.log_mul Real.log_mul
theorem log_div (hx : x ≠ 0) (hy : y ≠ 0) : log (x / y) = log x - log y :=
exp_injective <| by
rw [exp_log_eq_abs (div_ne_zero hx hy), exp_sub, exp_log_eq_abs hx, exp_log_eq_abs hy, abs_div]
#align real.log_div Real.log_div
@[simp]
theorem log_inv (x : ℝ) : log x⁻¹ = -log x := by
by_cases hx : x = 0; · simp [hx]
rw [← exp_eq_exp, exp_log_eq_abs (inv_ne_zero hx), exp_neg, exp_log_eq_abs hx, abs_inv]
#align real.log_inv Real.log_inv
theorem log_le_log_iff (h : 0 < x) (h₁ : 0 < y) : log x ≤ log y ↔ x ≤ y := by
rw [← exp_le_exp, exp_log h, exp_log h₁]
#align real.log_le_log Real.log_le_log_iff
@[gcongr]
lemma log_le_log (hx : 0 < x) (hxy : x ≤ y) : log x ≤ log y :=
(log_le_log_iff hx (hx.trans_le hxy)).2 hxy
@[gcongr]
theorem log_lt_log (hx : 0 < x) (h : x < y) : log x < log y := by
rwa [← exp_lt_exp, exp_log hx, exp_log (lt_trans hx h)]
#align real.log_lt_log Real.log_lt_log
theorem log_lt_log_iff (hx : 0 < x) (hy : 0 < y) : log x < log y ↔ x < y := by
rw [← exp_lt_exp, exp_log hx, exp_log hy]
#align real.log_lt_log_iff Real.log_lt_log_iff
theorem log_le_iff_le_exp (hx : 0 < x) : log x ≤ y ↔ x ≤ exp y := by rw [← exp_le_exp, exp_log hx]
#align real.log_le_iff_le_exp Real.log_le_iff_le_exp
theorem log_lt_iff_lt_exp (hx : 0 < x) : log x < y ↔ x < exp y := by rw [← exp_lt_exp, exp_log hx]
#align real.log_lt_iff_lt_exp Real.log_lt_iff_lt_exp
theorem le_log_iff_exp_le (hy : 0 < y) : x ≤ log y ↔ exp x ≤ y := by rw [← exp_le_exp, exp_log hy]
#align real.le_log_iff_exp_le Real.le_log_iff_exp_le
theorem lt_log_iff_exp_lt (hy : 0 < y) : x < log y ↔ exp x < y := by rw [← exp_lt_exp, exp_log hy]
#align real.lt_log_iff_exp_lt Real.lt_log_iff_exp_lt
theorem log_pos_iff (hx : 0 < x) : 0 < log x ↔ 1 < x := by
rw [← log_one]
exact log_lt_log_iff zero_lt_one hx
#align real.log_pos_iff Real.log_pos_iff
theorem log_pos (hx : 1 < x) : 0 < log x :=
(log_pos_iff (lt_trans zero_lt_one hx)).2 hx
#align real.log_pos Real.log_pos
theorem log_pos_of_lt_neg_one (hx : x < -1) : 0 < log x := by
rw [← neg_neg x, log_neg_eq_log]
have : 1 < -x := by linarith
exact log_pos this
theorem log_neg_iff (h : 0 < x) : log x < 0 ↔ x < 1 := by
rw [← log_one]
exact log_lt_log_iff h zero_lt_one
#align real.log_neg_iff Real.log_neg_iff
theorem log_neg (h0 : 0 < x) (h1 : x < 1) : log x < 0 :=
(log_neg_iff h0).2 h1
#align real.log_neg Real.log_neg
theorem log_neg_of_lt_zero (h0 : x < 0) (h1 : -1 < x) : log x < 0 := by
rw [← neg_neg x, log_neg_eq_log]
have h0' : 0 < -x := by linarith
have h1' : -x < 1 := by linarith
exact log_neg h0' h1'
| Mathlib/Analysis/SpecialFunctions/Log/Basic.lean | 200 | 200 | theorem log_nonneg_iff (hx : 0 < x) : 0 ≤ log x ↔ 1 ≤ x := by | rw [← not_lt, log_neg_iff hx, not_lt]
|
import Mathlib.CategoryTheory.Limits.Shapes.WidePullbacks
import Mathlib.CategoryTheory.Limits.Shapes.BinaryProducts
#align_import category_theory.limits.shapes.pullbacks from "leanprover-community/mathlib"@"7316286ff2942aa14e540add9058c6b0aa1c8070"
noncomputable section
open CategoryTheory
universe w v₁ v₂ v u u₂
namespace CategoryTheory.Limits
-- attribute [local tidy] tactic.case_bash Porting note: no tidy, no local
abbrev WalkingCospan : Type :=
WidePullbackShape WalkingPair
#align category_theory.limits.walking_cospan CategoryTheory.Limits.WalkingCospan
@[match_pattern]
abbrev WalkingCospan.left : WalkingCospan :=
some WalkingPair.left
#align category_theory.limits.walking_cospan.left CategoryTheory.Limits.WalkingCospan.left
@[match_pattern]
abbrev WalkingCospan.right : WalkingCospan :=
some WalkingPair.right
#align category_theory.limits.walking_cospan.right CategoryTheory.Limits.WalkingCospan.right
@[match_pattern]
abbrev WalkingCospan.one : WalkingCospan :=
none
#align category_theory.limits.walking_cospan.one CategoryTheory.Limits.WalkingCospan.one
abbrev WalkingSpan : Type :=
WidePushoutShape WalkingPair
#align category_theory.limits.walking_span CategoryTheory.Limits.WalkingSpan
@[match_pattern]
abbrev WalkingSpan.left : WalkingSpan :=
some WalkingPair.left
#align category_theory.limits.walking_span.left CategoryTheory.Limits.WalkingSpan.left
@[match_pattern]
abbrev WalkingSpan.right : WalkingSpan :=
some WalkingPair.right
#align category_theory.limits.walking_span.right CategoryTheory.Limits.WalkingSpan.right
@[match_pattern]
abbrev WalkingSpan.zero : WalkingSpan :=
none
#align category_theory.limits.walking_span.zero CategoryTheory.Limits.WalkingSpan.zero
open WalkingSpan.Hom WalkingCospan.Hom WidePullbackShape.Hom WidePushoutShape.Hom
variable {C : Type u} [Category.{v} C]
def WalkingCospan.ext {F : WalkingCospan ⥤ C} {s t : Cone F} (i : s.pt ≅ t.pt)
(w₁ : s.π.app WalkingCospan.left = i.hom ≫ t.π.app WalkingCospan.left)
(w₂ : s.π.app WalkingCospan.right = i.hom ≫ t.π.app WalkingCospan.right) : s ≅ t := by
apply Cones.ext i _
rintro (⟨⟩ | ⟨⟨⟩⟩)
· have h₁ := s.π.naturality WalkingCospan.Hom.inl
dsimp at h₁
simp only [Category.id_comp] at h₁
have h₂ := t.π.naturality WalkingCospan.Hom.inl
dsimp at h₂
simp only [Category.id_comp] at h₂
simp_rw [h₂, ← Category.assoc, ← w₁, ← h₁]
· exact w₁
· exact w₂
#align category_theory.limits.walking_cospan.ext CategoryTheory.Limits.WalkingCospan.ext
def WalkingSpan.ext {F : WalkingSpan ⥤ C} {s t : Cocone F} (i : s.pt ≅ t.pt)
(w₁ : s.ι.app WalkingCospan.left ≫ i.hom = t.ι.app WalkingCospan.left)
(w₂ : s.ι.app WalkingCospan.right ≫ i.hom = t.ι.app WalkingCospan.right) : s ≅ t := by
apply Cocones.ext i _
rintro (⟨⟩ | ⟨⟨⟩⟩)
· have h₁ := s.ι.naturality WalkingSpan.Hom.fst
dsimp at h₁
simp only [Category.comp_id] at h₁
have h₂ := t.ι.naturality WalkingSpan.Hom.fst
dsimp at h₂
simp only [Category.comp_id] at h₂
simp_rw [← h₁, Category.assoc, w₁, h₂]
· exact w₁
· exact w₂
#align category_theory.limits.walking_span.ext CategoryTheory.Limits.WalkingSpan.ext
def cospan {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : WalkingCospan ⥤ C :=
WidePullbackShape.wideCospan Z (fun j => WalkingPair.casesOn j X Y) fun j =>
WalkingPair.casesOn j f g
#align category_theory.limits.cospan CategoryTheory.Limits.cospan
def span {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : WalkingSpan ⥤ C :=
WidePushoutShape.wideSpan X (fun j => WalkingPair.casesOn j Y Z) fun j =>
WalkingPair.casesOn j f g
#align category_theory.limits.span CategoryTheory.Limits.span
@[simp]
theorem cospan_left {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : (cospan f g).obj WalkingCospan.left = X :=
rfl
#align category_theory.limits.cospan_left CategoryTheory.Limits.cospan_left
@[simp]
theorem span_left {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).obj WalkingSpan.left = Y :=
rfl
#align category_theory.limits.span_left CategoryTheory.Limits.span_left
@[simp]
theorem cospan_right {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) :
(cospan f g).obj WalkingCospan.right = Y := rfl
#align category_theory.limits.cospan_right CategoryTheory.Limits.cospan_right
@[simp]
theorem span_right {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).obj WalkingSpan.right = Z :=
rfl
#align category_theory.limits.span_right CategoryTheory.Limits.span_right
@[simp]
theorem cospan_one {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : (cospan f g).obj WalkingCospan.one = Z :=
rfl
#align category_theory.limits.cospan_one CategoryTheory.Limits.cospan_one
@[simp]
theorem span_zero {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).obj WalkingSpan.zero = X :=
rfl
#align category_theory.limits.span_zero CategoryTheory.Limits.span_zero
@[simp]
theorem cospan_map_inl {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) :
(cospan f g).map WalkingCospan.Hom.inl = f := rfl
#align category_theory.limits.cospan_map_inl CategoryTheory.Limits.cospan_map_inl
@[simp]
theorem span_map_fst {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).map WalkingSpan.Hom.fst = f :=
rfl
#align category_theory.limits.span_map_fst CategoryTheory.Limits.span_map_fst
@[simp]
theorem cospan_map_inr {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) :
(cospan f g).map WalkingCospan.Hom.inr = g := rfl
#align category_theory.limits.cospan_map_inr CategoryTheory.Limits.cospan_map_inr
@[simp]
theorem span_map_snd {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).map WalkingSpan.Hom.snd = g :=
rfl
#align category_theory.limits.span_map_snd CategoryTheory.Limits.span_map_snd
theorem cospan_map_id {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) (w : WalkingCospan) :
(cospan f g).map (WalkingCospan.Hom.id w) = 𝟙 _ := rfl
#align category_theory.limits.cospan_map_id CategoryTheory.Limits.cospan_map_id
theorem span_map_id {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) (w : WalkingSpan) :
(span f g).map (WalkingSpan.Hom.id w) = 𝟙 _ := rfl
#align category_theory.limits.span_map_id CategoryTheory.Limits.span_map_id
-- @[simps (config := { rhsMd := semireducible })] Porting note: no semireducible
@[simps!]
def diagramIsoCospan (F : WalkingCospan ⥤ C) : F ≅ cospan (F.map inl) (F.map inr) :=
NatIso.ofComponents
(fun j => eqToIso (by rcases j with (⟨⟩ | ⟨⟨⟩⟩) <;> rfl))
(by rintro (⟨⟩ | ⟨⟨⟩⟩) (⟨⟩ | ⟨⟨⟩⟩) f <;> cases f <;> dsimp <;> simp)
#align category_theory.limits.diagram_iso_cospan CategoryTheory.Limits.diagramIsoCospan
-- @[simps (config := { rhsMd := semireducible })] Porting note: no semireducible
@[simps!]
def diagramIsoSpan (F : WalkingSpan ⥤ C) : F ≅ span (F.map fst) (F.map snd) :=
NatIso.ofComponents
(fun j => eqToIso (by rcases j with (⟨⟩ | ⟨⟨⟩⟩) <;> rfl))
(by rintro (⟨⟩ | ⟨⟨⟩⟩) (⟨⟩ | ⟨⟨⟩⟩) f <;> cases f <;> dsimp <;> simp)
#align category_theory.limits.diagram_iso_span CategoryTheory.Limits.diagramIsoSpan
variable {D : Type u₂} [Category.{v₂} D]
def cospanCompIso (F : C ⥤ D) {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) :
cospan f g ⋙ F ≅ cospan (F.map f) (F.map g) :=
NatIso.ofComponents (by rintro (⟨⟩ | ⟨⟨⟩⟩) <;> exact Iso.refl _)
(by rintro (⟨⟩ | ⟨⟨⟩⟩) (⟨⟩ | ⟨⟨⟩⟩) f <;> cases f <;> dsimp <;> simp)
#align category_theory.limits.cospan_comp_iso CategoryTheory.Limits.cospanCompIso
section
variable (F : C ⥤ D) {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z)
@[simp]
theorem cospanCompIso_app_left : (cospanCompIso F f g).app WalkingCospan.left = Iso.refl _ := rfl
#align category_theory.limits.cospan_comp_iso_app_left CategoryTheory.Limits.cospanCompIso_app_left
@[simp]
theorem cospanCompIso_app_right : (cospanCompIso F f g).app WalkingCospan.right = Iso.refl _ :=
rfl
#align category_theory.limits.cospan_comp_iso_app_right CategoryTheory.Limits.cospanCompIso_app_right
@[simp]
theorem cospanCompIso_app_one : (cospanCompIso F f g).app WalkingCospan.one = Iso.refl _ := rfl
#align category_theory.limits.cospan_comp_iso_app_one CategoryTheory.Limits.cospanCompIso_app_one
@[simp]
theorem cospanCompIso_hom_app_left : (cospanCompIso F f g).hom.app WalkingCospan.left = 𝟙 _ :=
rfl
#align category_theory.limits.cospan_comp_iso_hom_app_left CategoryTheory.Limits.cospanCompIso_hom_app_left
@[simp]
theorem cospanCompIso_hom_app_right : (cospanCompIso F f g).hom.app WalkingCospan.right = 𝟙 _ :=
rfl
#align category_theory.limits.cospan_comp_iso_hom_app_right CategoryTheory.Limits.cospanCompIso_hom_app_right
@[simp]
theorem cospanCompIso_hom_app_one : (cospanCompIso F f g).hom.app WalkingCospan.one = 𝟙 _ := rfl
#align category_theory.limits.cospan_comp_iso_hom_app_one CategoryTheory.Limits.cospanCompIso_hom_app_one
@[simp]
theorem cospanCompIso_inv_app_left : (cospanCompIso F f g).inv.app WalkingCospan.left = 𝟙 _ :=
rfl
#align category_theory.limits.cospan_comp_iso_inv_app_left CategoryTheory.Limits.cospanCompIso_inv_app_left
@[simp]
theorem cospanCompIso_inv_app_right : (cospanCompIso F f g).inv.app WalkingCospan.right = 𝟙 _ :=
rfl
#align category_theory.limits.cospan_comp_iso_inv_app_right CategoryTheory.Limits.cospanCompIso_inv_app_right
@[simp]
theorem cospanCompIso_inv_app_one : (cospanCompIso F f g).inv.app WalkingCospan.one = 𝟙 _ := rfl
#align category_theory.limits.cospan_comp_iso_inv_app_one CategoryTheory.Limits.cospanCompIso_inv_app_one
end
def spanCompIso (F : C ⥤ D) {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) :
span f g ⋙ F ≅ span (F.map f) (F.map g) :=
NatIso.ofComponents (by rintro (⟨⟩ | ⟨⟨⟩⟩) <;> exact Iso.refl _)
(by rintro (⟨⟩ | ⟨⟨⟩⟩) (⟨⟩ | ⟨⟨⟩⟩) f <;> cases f <;> dsimp <;> simp)
#align category_theory.limits.span_comp_iso CategoryTheory.Limits.spanCompIso
section
variable (F : C ⥤ D) {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z)
@[simp]
theorem spanCompIso_app_left : (spanCompIso F f g).app WalkingSpan.left = Iso.refl _ := rfl
#align category_theory.limits.span_comp_iso_app_left CategoryTheory.Limits.spanCompIso_app_left
@[simp]
theorem spanCompIso_app_right : (spanCompIso F f g).app WalkingSpan.right = Iso.refl _ := rfl
#align category_theory.limits.span_comp_iso_app_right CategoryTheory.Limits.spanCompIso_app_right
@[simp]
theorem spanCompIso_app_zero : (spanCompIso F f g).app WalkingSpan.zero = Iso.refl _ := rfl
#align category_theory.limits.span_comp_iso_app_zero CategoryTheory.Limits.spanCompIso_app_zero
@[simp]
theorem spanCompIso_hom_app_left : (spanCompIso F f g).hom.app WalkingSpan.left = 𝟙 _ := rfl
#align category_theory.limits.span_comp_iso_hom_app_left CategoryTheory.Limits.spanCompIso_hom_app_left
@[simp]
theorem spanCompIso_hom_app_right : (spanCompIso F f g).hom.app WalkingSpan.right = 𝟙 _ := rfl
#align category_theory.limits.span_comp_iso_hom_app_right CategoryTheory.Limits.spanCompIso_hom_app_right
@[simp]
theorem spanCompIso_hom_app_zero : (spanCompIso F f g).hom.app WalkingSpan.zero = 𝟙 _ := rfl
#align category_theory.limits.span_comp_iso_hom_app_zero CategoryTheory.Limits.spanCompIso_hom_app_zero
@[simp]
theorem spanCompIso_inv_app_left : (spanCompIso F f g).inv.app WalkingSpan.left = 𝟙 _ := rfl
#align category_theory.limits.span_comp_iso_inv_app_left CategoryTheory.Limits.spanCompIso_inv_app_left
@[simp]
theorem spanCompIso_inv_app_right : (spanCompIso F f g).inv.app WalkingSpan.right = 𝟙 _ := rfl
#align category_theory.limits.span_comp_iso_inv_app_right CategoryTheory.Limits.spanCompIso_inv_app_right
@[simp]
theorem spanCompIso_inv_app_zero : (spanCompIso F f g).inv.app WalkingSpan.zero = 𝟙 _ := rfl
#align category_theory.limits.span_comp_iso_inv_app_zero CategoryTheory.Limits.spanCompIso_inv_app_zero
end
section
variable {X Y Z X' Y' Z' : C} (iX : X ≅ X') (iY : Y ≅ Y') (iZ : Z ≅ Z')
section
variable {f : X ⟶ Z} {g : Y ⟶ Z} {f' : X' ⟶ Z'} {g' : Y' ⟶ Z'}
def cospanExt (wf : iX.hom ≫ f' = f ≫ iZ.hom) (wg : iY.hom ≫ g' = g ≫ iZ.hom) :
cospan f g ≅ cospan f' g' :=
NatIso.ofComponents
(by rintro (⟨⟩ | ⟨⟨⟩⟩); exacts [iZ, iX, iY])
(by rintro (⟨⟩ | ⟨⟨⟩⟩) (⟨⟩ | ⟨⟨⟩⟩) f <;> cases f <;> dsimp <;> simp [wf, wg])
#align category_theory.limits.cospan_ext CategoryTheory.Limits.cospanExt
variable (wf : iX.hom ≫ f' = f ≫ iZ.hom) (wg : iY.hom ≫ g' = g ≫ iZ.hom)
@[simp]
theorem cospanExt_app_left : (cospanExt iX iY iZ wf wg).app WalkingCospan.left = iX := by
dsimp [cospanExt]
#align category_theory.limits.cospan_ext_app_left CategoryTheory.Limits.cospanExt_app_left
@[simp]
theorem cospanExt_app_right : (cospanExt iX iY iZ wf wg).app WalkingCospan.right = iY := by
dsimp [cospanExt]
#align category_theory.limits.cospan_ext_app_right CategoryTheory.Limits.cospanExt_app_right
@[simp]
theorem cospanExt_app_one : (cospanExt iX iY iZ wf wg).app WalkingCospan.one = iZ := by
dsimp [cospanExt]
#align category_theory.limits.cospan_ext_app_one CategoryTheory.Limits.cospanExt_app_one
@[simp]
theorem cospanExt_hom_app_left :
(cospanExt iX iY iZ wf wg).hom.app WalkingCospan.left = iX.hom := by dsimp [cospanExt]
#align category_theory.limits.cospan_ext_hom_app_left CategoryTheory.Limits.cospanExt_hom_app_left
@[simp]
theorem cospanExt_hom_app_right :
(cospanExt iX iY iZ wf wg).hom.app WalkingCospan.right = iY.hom := by dsimp [cospanExt]
#align category_theory.limits.cospan_ext_hom_app_right CategoryTheory.Limits.cospanExt_hom_app_right
@[simp]
theorem cospanExt_hom_app_one : (cospanExt iX iY iZ wf wg).hom.app WalkingCospan.one = iZ.hom := by
dsimp [cospanExt]
#align category_theory.limits.cospan_ext_hom_app_one CategoryTheory.Limits.cospanExt_hom_app_one
@[simp]
theorem cospanExt_inv_app_left :
(cospanExt iX iY iZ wf wg).inv.app WalkingCospan.left = iX.inv := by dsimp [cospanExt]
#align category_theory.limits.cospan_ext_inv_app_left CategoryTheory.Limits.cospanExt_inv_app_left
@[simp]
theorem cospanExt_inv_app_right :
(cospanExt iX iY iZ wf wg).inv.app WalkingCospan.right = iY.inv := by dsimp [cospanExt]
#align category_theory.limits.cospan_ext_inv_app_right CategoryTheory.Limits.cospanExt_inv_app_right
@[simp]
theorem cospanExt_inv_app_one : (cospanExt iX iY iZ wf wg).inv.app WalkingCospan.one = iZ.inv := by
dsimp [cospanExt]
#align category_theory.limits.cospan_ext_inv_app_one CategoryTheory.Limits.cospanExt_inv_app_one
end
section
variable {f : X ⟶ Y} {g : X ⟶ Z} {f' : X' ⟶ Y'} {g' : X' ⟶ Z'}
def spanExt (wf : iX.hom ≫ f' = f ≫ iY.hom) (wg : iX.hom ≫ g' = g ≫ iZ.hom) :
span f g ≅ span f' g' :=
NatIso.ofComponents (by rintro (⟨⟩ | ⟨⟨⟩⟩); exacts [iX, iY, iZ])
(by rintro (⟨⟩ | ⟨⟨⟩⟩) (⟨⟩ | ⟨⟨⟩⟩) f <;> cases f <;> dsimp <;> simp [wf, wg])
#align category_theory.limits.span_ext CategoryTheory.Limits.spanExt
variable (wf : iX.hom ≫ f' = f ≫ iY.hom) (wg : iX.hom ≫ g' = g ≫ iZ.hom)
@[simp]
theorem spanExt_app_left : (spanExt iX iY iZ wf wg).app WalkingSpan.left = iY := by
dsimp [spanExt]
#align category_theory.limits.span_ext_app_left CategoryTheory.Limits.spanExt_app_left
@[simp]
theorem spanExt_app_right : (spanExt iX iY iZ wf wg).app WalkingSpan.right = iZ := by
dsimp [spanExt]
#align category_theory.limits.span_ext_app_right CategoryTheory.Limits.spanExt_app_right
@[simp]
theorem spanExt_app_one : (spanExt iX iY iZ wf wg).app WalkingSpan.zero = iX := by
dsimp [spanExt]
#align category_theory.limits.span_ext_app_one CategoryTheory.Limits.spanExt_app_one
@[simp]
theorem spanExt_hom_app_left : (spanExt iX iY iZ wf wg).hom.app WalkingSpan.left = iY.hom := by
dsimp [spanExt]
#align category_theory.limits.span_ext_hom_app_left CategoryTheory.Limits.spanExt_hom_app_left
@[simp]
theorem spanExt_hom_app_right : (spanExt iX iY iZ wf wg).hom.app WalkingSpan.right = iZ.hom := by
dsimp [spanExt]
#align category_theory.limits.span_ext_hom_app_right CategoryTheory.Limits.spanExt_hom_app_right
@[simp]
theorem spanExt_hom_app_zero : (spanExt iX iY iZ wf wg).hom.app WalkingSpan.zero = iX.hom := by
dsimp [spanExt]
#align category_theory.limits.span_ext_hom_app_zero CategoryTheory.Limits.spanExt_hom_app_zero
@[simp]
theorem spanExt_inv_app_left : (spanExt iX iY iZ wf wg).inv.app WalkingSpan.left = iY.inv := by
dsimp [spanExt]
#align category_theory.limits.span_ext_inv_app_left CategoryTheory.Limits.spanExt_inv_app_left
@[simp]
theorem spanExt_inv_app_right : (spanExt iX iY iZ wf wg).inv.app WalkingSpan.right = iZ.inv := by
dsimp [spanExt]
#align category_theory.limits.span_ext_inv_app_right CategoryTheory.Limits.spanExt_inv_app_right
@[simp]
theorem spanExt_inv_app_zero : (spanExt iX iY iZ wf wg).inv.app WalkingSpan.zero = iX.inv := by
dsimp [spanExt]
#align category_theory.limits.span_ext_inv_app_zero CategoryTheory.Limits.spanExt_inv_app_zero
end
end
variable {W X Y Z : C}
abbrev PullbackCone (f : X ⟶ Z) (g : Y ⟶ Z) :=
Cone (cospan f g)
#align category_theory.limits.pullback_cone CategoryTheory.Limits.PullbackCone
namespace PullbackCone
variable {f : X ⟶ Z} {g : Y ⟶ Z}
abbrev fst (t : PullbackCone f g) : t.pt ⟶ X :=
t.π.app WalkingCospan.left
#align category_theory.limits.pullback_cone.fst CategoryTheory.Limits.PullbackCone.fst
abbrev snd (t : PullbackCone f g) : t.pt ⟶ Y :=
t.π.app WalkingCospan.right
#align category_theory.limits.pullback_cone.snd CategoryTheory.Limits.PullbackCone.snd
@[simp]
theorem π_app_left (c : PullbackCone f g) : c.π.app WalkingCospan.left = c.fst := rfl
#align category_theory.limits.pullback_cone.π_app_left CategoryTheory.Limits.PullbackCone.π_app_left
@[simp]
theorem π_app_right (c : PullbackCone f g) : c.π.app WalkingCospan.right = c.snd := rfl
#align category_theory.limits.pullback_cone.π_app_right CategoryTheory.Limits.PullbackCone.π_app_right
@[simp]
theorem condition_one (t : PullbackCone f g) : t.π.app WalkingCospan.one = t.fst ≫ f := by
have w := t.π.naturality WalkingCospan.Hom.inl
dsimp at w; simpa using w
#align category_theory.limits.pullback_cone.condition_one CategoryTheory.Limits.PullbackCone.condition_one
def isLimitAux (t : PullbackCone f g) (lift : ∀ s : PullbackCone f g, s.pt ⟶ t.pt)
(fac_left : ∀ s : PullbackCone f g, lift s ≫ t.fst = s.fst)
(fac_right : ∀ s : PullbackCone f g, lift s ≫ t.snd = s.snd)
(uniq : ∀ (s : PullbackCone f g) (m : s.pt ⟶ t.pt)
(_ : ∀ j : WalkingCospan, m ≫ t.π.app j = s.π.app j), m = lift s) : IsLimit t :=
{ lift
fac := fun s j => Option.casesOn j (by
rw [← s.w inl, ← t.w inl, ← Category.assoc]
congr
exact fac_left s)
fun j' => WalkingPair.casesOn j' (fac_left s) (fac_right s)
uniq := uniq }
#align category_theory.limits.pullback_cone.is_limit_aux CategoryTheory.Limits.PullbackCone.isLimitAux
def isLimitAux' (t : PullbackCone f g)
(create :
∀ s : PullbackCone f g,
{ l //
l ≫ t.fst = s.fst ∧
l ≫ t.snd = s.snd ∧ ∀ {m}, m ≫ t.fst = s.fst → m ≫ t.snd = s.snd → m = l }) :
Limits.IsLimit t :=
PullbackCone.isLimitAux t (fun s => (create s).1) (fun s => (create s).2.1)
(fun s => (create s).2.2.1) fun s _ w =>
(create s).2.2.2 (w WalkingCospan.left) (w WalkingCospan.right)
#align category_theory.limits.pullback_cone.is_limit_aux' CategoryTheory.Limits.PullbackCone.isLimitAux'
@[simps]
def mk {W : C} (fst : W ⟶ X) (snd : W ⟶ Y) (eq : fst ≫ f = snd ≫ g) : PullbackCone f g where
pt := W
π := { app := fun j => Option.casesOn j (fst ≫ f) fun j' => WalkingPair.casesOn j' fst snd
naturality := by rintro (⟨⟩ | ⟨⟨⟩⟩) (⟨⟩ | ⟨⟨⟩⟩) j <;> cases j <;> dsimp <;> simp [eq] }
#align category_theory.limits.pullback_cone.mk CategoryTheory.Limits.PullbackCone.mk
@[simp]
theorem mk_π_app_left {W : C} (fst : W ⟶ X) (snd : W ⟶ Y) (eq : fst ≫ f = snd ≫ g) :
(mk fst snd eq).π.app WalkingCospan.left = fst := rfl
#align category_theory.limits.pullback_cone.mk_π_app_left CategoryTheory.Limits.PullbackCone.mk_π_app_left
@[simp]
theorem mk_π_app_right {W : C} (fst : W ⟶ X) (snd : W ⟶ Y) (eq : fst ≫ f = snd ≫ g) :
(mk fst snd eq).π.app WalkingCospan.right = snd := rfl
#align category_theory.limits.pullback_cone.mk_π_app_right CategoryTheory.Limits.PullbackCone.mk_π_app_right
@[simp]
theorem mk_π_app_one {W : C} (fst : W ⟶ X) (snd : W ⟶ Y) (eq : fst ≫ f = snd ≫ g) :
(mk fst snd eq).π.app WalkingCospan.one = fst ≫ f := rfl
#align category_theory.limits.pullback_cone.mk_π_app_one CategoryTheory.Limits.PullbackCone.mk_π_app_one
@[simp]
theorem mk_fst {W : C} (fst : W ⟶ X) (snd : W ⟶ Y) (eq : fst ≫ f = snd ≫ g) :
(mk fst snd eq).fst = fst := rfl
#align category_theory.limits.pullback_cone.mk_fst CategoryTheory.Limits.PullbackCone.mk_fst
@[simp]
theorem mk_snd {W : C} (fst : W ⟶ X) (snd : W ⟶ Y) (eq : fst ≫ f = snd ≫ g) :
(mk fst snd eq).snd = snd := rfl
#align category_theory.limits.pullback_cone.mk_snd CategoryTheory.Limits.PullbackCone.mk_snd
@[reassoc]
theorem condition (t : PullbackCone f g) : fst t ≫ f = snd t ≫ g :=
(t.w inl).trans (t.w inr).symm
#align category_theory.limits.pullback_cone.condition CategoryTheory.Limits.PullbackCone.condition
theorem equalizer_ext (t : PullbackCone f g) {W : C} {k l : W ⟶ t.pt} (h₀ : k ≫ fst t = l ≫ fst t)
(h₁ : k ≫ snd t = l ≫ snd t) : ∀ j : WalkingCospan, k ≫ t.π.app j = l ≫ t.π.app j
| some WalkingPair.left => h₀
| some WalkingPair.right => h₁
| none => by rw [← t.w inl, reassoc_of% h₀]
#align category_theory.limits.pullback_cone.equalizer_ext CategoryTheory.Limits.PullbackCone.equalizer_ext
theorem IsLimit.hom_ext {t : PullbackCone f g} (ht : IsLimit t) {W : C} {k l : W ⟶ t.pt}
(h₀ : k ≫ fst t = l ≫ fst t) (h₁ : k ≫ snd t = l ≫ snd t) : k = l :=
ht.hom_ext <| equalizer_ext _ h₀ h₁
#align category_theory.limits.pullback_cone.is_limit.hom_ext CategoryTheory.Limits.PullbackCone.IsLimit.hom_ext
theorem mono_snd_of_is_pullback_of_mono {t : PullbackCone f g} (ht : IsLimit t) [Mono f] :
Mono t.snd := by
refine ⟨fun {W} h k i => IsLimit.hom_ext ht ?_ i⟩
rw [← cancel_mono f, Category.assoc, Category.assoc, condition]
have := congrArg (· ≫ g) i; dsimp at this
rwa [Category.assoc, Category.assoc] at this
#align category_theory.limits.pullback_cone.mono_snd_of_is_pullback_of_mono CategoryTheory.Limits.PullbackCone.mono_snd_of_is_pullback_of_mono
theorem mono_fst_of_is_pullback_of_mono {t : PullbackCone f g} (ht : IsLimit t) [Mono g] :
Mono t.fst := by
refine ⟨fun {W} h k i => IsLimit.hom_ext ht i ?_⟩
rw [← cancel_mono g, Category.assoc, Category.assoc, ← condition]
have := congrArg (· ≫ f) i; dsimp at this
rwa [Category.assoc, Category.assoc] at this
#align category_theory.limits.pullback_cone.mono_fst_of_is_pullback_of_mono CategoryTheory.Limits.PullbackCone.mono_fst_of_is_pullback_of_mono
def ext {s t : PullbackCone f g} (i : s.pt ≅ t.pt) (w₁ : s.fst = i.hom ≫ t.fst)
(w₂ : s.snd = i.hom ≫ t.snd) : s ≅ t :=
WalkingCospan.ext i w₁ w₂
#align category_theory.limits.pullback_cone.ext CategoryTheory.Limits.PullbackCone.ext
-- Porting note: `IsLimit.lift` and the two following simp lemmas were introduced to ease the port
def IsLimit.lift {t : PullbackCone f g} (ht : IsLimit t) {W : C} (h : W ⟶ X) (k : W ⟶ Y)
(w : h ≫ f = k ≫ g) : W ⟶ t.pt :=
ht.lift <| PullbackCone.mk _ _ w
@[reassoc (attr := simp)]
lemma IsLimit.lift_fst {t : PullbackCone f g} (ht : IsLimit t) {W : C} (h : W ⟶ X) (k : W ⟶ Y)
(w : h ≫ f = k ≫ g) : IsLimit.lift ht h k w ≫ fst t = h := ht.fac _ _
@[reassoc (attr := simp)]
lemma IsLimit.lift_snd {t : PullbackCone f g} (ht : IsLimit t) {W : C} (h : W ⟶ X) (k : W ⟶ Y)
(w : h ≫ f = k ≫ g) : IsLimit.lift ht h k w ≫ snd t = k := ht.fac _ _
def IsLimit.lift' {t : PullbackCone f g} (ht : IsLimit t) {W : C} (h : W ⟶ X) (k : W ⟶ Y)
(w : h ≫ f = k ≫ g) : { l : W ⟶ t.pt // l ≫ fst t = h ∧ l ≫ snd t = k } :=
⟨IsLimit.lift ht h k w, by simp⟩
#align category_theory.limits.pullback_cone.is_limit.lift' CategoryTheory.Limits.PullbackCone.IsLimit.lift'
def IsLimit.mk {W : C} {fst : W ⟶ X} {snd : W ⟶ Y} (eq : fst ≫ f = snd ≫ g)
(lift : ∀ s : PullbackCone f g, s.pt ⟶ W)
(fac_left : ∀ s : PullbackCone f g, lift s ≫ fst = s.fst)
(fac_right : ∀ s : PullbackCone f g, lift s ≫ snd = s.snd)
(uniq :
∀ (s : PullbackCone f g) (m : s.pt ⟶ W) (_ : m ≫ fst = s.fst) (_ : m ≫ snd = s.snd),
m = lift s) :
IsLimit (mk fst snd eq) :=
isLimitAux _ lift fac_left fac_right fun s m w =>
uniq s m (w WalkingCospan.left) (w WalkingCospan.right)
#align category_theory.limits.pullback_cone.is_limit.mk CategoryTheory.Limits.PullbackCone.IsLimit.mk
@[simps]
def Cone.ofPullbackCone {F : WalkingCospan ⥤ C} (t : PullbackCone (F.map inl) (F.map inr)) :
Cone F where
pt := t.pt
π := t.π ≫ (diagramIsoCospan F).inv
#align category_theory.limits.cone.of_pullback_cone CategoryTheory.Limits.Cone.ofPullbackCone
@[simps]
def Cocone.ofPushoutCocone {F : WalkingSpan ⥤ C} (t : PushoutCocone (F.map fst) (F.map snd)) :
Cocone F where
pt := t.pt
ι := (diagramIsoSpan F).hom ≫ t.ι
#align category_theory.limits.cocone.of_pushout_cocone CategoryTheory.Limits.Cocone.ofPushoutCocone
@[simps]
def PullbackCone.ofCone {F : WalkingCospan ⥤ C} (t : Cone F) :
PullbackCone (F.map inl) (F.map inr) where
pt := t.pt
π := t.π ≫ (diagramIsoCospan F).hom
#align category_theory.limits.pullback_cone.of_cone CategoryTheory.Limits.PullbackCone.ofCone
@[simps!]
def PullbackCone.isoMk {F : WalkingCospan ⥤ C} (t : Cone F) :
(Cones.postcompose (diagramIsoCospan.{v} _).hom).obj t ≅
PullbackCone.mk (t.π.app WalkingCospan.left) (t.π.app WalkingCospan.right)
((t.π.naturality inl).symm.trans (t.π.naturality inr : _)) :=
Cones.ext (Iso.refl _) <| by
rintro (_ | (_ | _)) <;>
· dsimp
simp
#align category_theory.limits.pullback_cone.iso_mk CategoryTheory.Limits.PullbackCone.isoMk
@[simps]
def PushoutCocone.ofCocone {F : WalkingSpan ⥤ C} (t : Cocone F) :
PushoutCocone (F.map fst) (F.map snd) where
pt := t.pt
ι := (diagramIsoSpan F).inv ≫ t.ι
#align category_theory.limits.pushout_cocone.of_cocone CategoryTheory.Limits.PushoutCocone.ofCocone
@[simps!]
def PushoutCocone.isoMk {F : WalkingSpan ⥤ C} (t : Cocone F) :
(Cocones.precompose (diagramIsoSpan.{v} _).inv).obj t ≅
PushoutCocone.mk (t.ι.app WalkingSpan.left) (t.ι.app WalkingSpan.right)
((t.ι.naturality fst).trans (t.ι.naturality snd).symm) :=
Cocones.ext (Iso.refl _) <| by
rintro (_ | (_ | _)) <;>
· dsimp
simp
#align category_theory.limits.pushout_cocone.iso_mk CategoryTheory.Limits.PushoutCocone.isoMk
abbrev HasPullback {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) :=
HasLimit (cospan f g)
#align category_theory.limits.has_pullback CategoryTheory.Limits.HasPullback
abbrev HasPushout {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) :=
HasColimit (span f g)
#align category_theory.limits.has_pushout CategoryTheory.Limits.HasPushout
abbrev pullback {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) [HasPullback f g] :=
limit (cospan f g)
#align category_theory.limits.pullback CategoryTheory.Limits.pullback
abbrev pushout {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) [HasPushout f g] :=
colimit (span f g)
#align category_theory.limits.pushout CategoryTheory.Limits.pushout
abbrev pullback.fst {X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] : pullback f g ⟶ X :=
limit.π (cospan f g) WalkingCospan.left
#align category_theory.limits.pullback.fst CategoryTheory.Limits.pullback.fst
abbrev pullback.snd {X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] : pullback f g ⟶ Y :=
limit.π (cospan f g) WalkingCospan.right
#align category_theory.limits.pullback.snd CategoryTheory.Limits.pullback.snd
abbrev pushout.inl {X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] : Y ⟶ pushout f g :=
colimit.ι (span f g) WalkingSpan.left
#align category_theory.limits.pushout.inl CategoryTheory.Limits.pushout.inl
abbrev pushout.inr {X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] : Z ⟶ pushout f g :=
colimit.ι (span f g) WalkingSpan.right
#align category_theory.limits.pushout.inr CategoryTheory.Limits.pushout.inr
abbrev pullback.lift {W X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] (h : W ⟶ X) (k : W ⟶ Y)
(w : h ≫ f = k ≫ g) : W ⟶ pullback f g :=
limit.lift _ (PullbackCone.mk h k w)
#align category_theory.limits.pullback.lift CategoryTheory.Limits.pullback.lift
abbrev pushout.desc {W X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] (h : Y ⟶ W) (k : Z ⟶ W)
(w : f ≫ h = g ≫ k) : pushout f g ⟶ W :=
colimit.desc _ (PushoutCocone.mk h k w)
#align category_theory.limits.pushout.desc CategoryTheory.Limits.pushout.desc
@[simp]
theorem PullbackCone.fst_colimit_cocone {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z)
[HasLimit (cospan f g)] : PullbackCone.fst (limit.cone (cospan f g)) = pullback.fst := rfl
#align category_theory.limits.pullback_cone.fst_colimit_cocone CategoryTheory.Limits.PullbackCone.fst_colimit_cocone
@[simp]
theorem PullbackCone.snd_colimit_cocone {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z)
[HasLimit (cospan f g)] : PullbackCone.snd (limit.cone (cospan f g)) = pullback.snd := rfl
#align category_theory.limits.pullback_cone.snd_colimit_cocone CategoryTheory.Limits.PullbackCone.snd_colimit_cocone
-- Porting note (#10618): simp can prove this; removed simp
theorem PushoutCocone.inl_colimit_cocone {X Y Z : C} (f : Z ⟶ X) (g : Z ⟶ Y)
[HasColimit (span f g)] : PushoutCocone.inl (colimit.cocone (span f g)) = pushout.inl := rfl
#align category_theory.limits.pushout_cocone.inl_colimit_cocone CategoryTheory.Limits.PushoutCocone.inl_colimit_cocone
-- Porting note (#10618): simp can prove this; removed simp
theorem PushoutCocone.inr_colimit_cocone {X Y Z : C} (f : Z ⟶ X) (g : Z ⟶ Y)
[HasColimit (span f g)] : PushoutCocone.inr (colimit.cocone (span f g)) = pushout.inr := rfl
#align category_theory.limits.pushout_cocone.inr_colimit_cocone CategoryTheory.Limits.PushoutCocone.inr_colimit_cocone
-- Porting note (#10618): simp can prove this and reassoced version; removed simp
@[reassoc]
theorem pullback.lift_fst {W X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] (h : W ⟶ X)
(k : W ⟶ Y) (w : h ≫ f = k ≫ g) : pullback.lift h k w ≫ pullback.fst = h :=
limit.lift_π _ _
#align category_theory.limits.pullback.lift_fst CategoryTheory.Limits.pullback.lift_fst
-- Porting note (#10618): simp can prove this and reassoced version; removed simp
@[reassoc]
theorem pullback.lift_snd {W X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] (h : W ⟶ X)
(k : W ⟶ Y) (w : h ≫ f = k ≫ g) : pullback.lift h k w ≫ pullback.snd = k :=
limit.lift_π _ _
#align category_theory.limits.pullback.lift_snd CategoryTheory.Limits.pullback.lift_snd
-- Porting note (#10618): simp can prove this and reassoced version; removed simp
@[reassoc]
theorem pushout.inl_desc {W X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] (h : Y ⟶ W)
(k : Z ⟶ W) (w : f ≫ h = g ≫ k) : pushout.inl ≫ pushout.desc h k w = h :=
colimit.ι_desc _ _
#align category_theory.limits.pushout.inl_desc CategoryTheory.Limits.pushout.inl_desc
-- Porting note (#10618): simp can prove this and reassoced version; removed simp
@[reassoc]
theorem pushout.inr_desc {W X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] (h : Y ⟶ W)
(k : Z ⟶ W) (w : f ≫ h = g ≫ k) : pushout.inr ≫ pushout.desc h k w = k :=
colimit.ι_desc _ _
#align category_theory.limits.pushout.inr_desc CategoryTheory.Limits.pushout.inr_desc
def pullback.lift' {W X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] (h : W ⟶ X) (k : W ⟶ Y)
(w : h ≫ f = k ≫ g) : { l : W ⟶ pullback f g // l ≫ pullback.fst = h ∧ l ≫ pullback.snd = k } :=
⟨pullback.lift h k w, pullback.lift_fst _ _ _, pullback.lift_snd _ _ _⟩
#align category_theory.limits.pullback.lift' CategoryTheory.Limits.pullback.lift'
def pullback.desc' {W X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] (h : Y ⟶ W) (k : Z ⟶ W)
(w : f ≫ h = g ≫ k) : { l : pushout f g ⟶ W // pushout.inl ≫ l = h ∧ pushout.inr ≫ l = k } :=
⟨pushout.desc h k w, pushout.inl_desc _ _ _, pushout.inr_desc _ _ _⟩
#align category_theory.limits.pullback.desc' CategoryTheory.Limits.pullback.desc'
@[reassoc]
theorem pullback.condition {X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] :
(pullback.fst : pullback f g ⟶ X) ≫ f = pullback.snd ≫ g :=
PullbackCone.condition _
#align category_theory.limits.pullback.condition CategoryTheory.Limits.pullback.condition
@[reassoc]
theorem pushout.condition {X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] :
f ≫ (pushout.inl : Y ⟶ pushout f g) = g ≫ pushout.inr :=
PushoutCocone.condition _
#align category_theory.limits.pushout.condition CategoryTheory.Limits.pushout.condition
abbrev pullback.map {W X Y Z S T : C} (f₁ : W ⟶ S) (f₂ : X ⟶ S) [HasPullback f₁ f₂] (g₁ : Y ⟶ T)
(g₂ : Z ⟶ T) [HasPullback g₁ g₂] (i₁ : W ⟶ Y) (i₂ : X ⟶ Z) (i₃ : S ⟶ T)
(eq₁ : f₁ ≫ i₃ = i₁ ≫ g₁) (eq₂ : f₂ ≫ i₃ = i₂ ≫ g₂) : pullback f₁ f₂ ⟶ pullback g₁ g₂ :=
pullback.lift (pullback.fst ≫ i₁) (pullback.snd ≫ i₂)
(by simp [← eq₁, ← eq₂, pullback.condition_assoc])
#align category_theory.limits.pullback.map CategoryTheory.Limits.pullback.map
abbrev pullback.mapDesc {X Y S T : C} (f : X ⟶ S) (g : Y ⟶ S) (i : S ⟶ T) [HasPullback f g]
[HasPullback (f ≫ i) (g ≫ i)] : pullback f g ⟶ pullback (f ≫ i) (g ≫ i) :=
pullback.map f g (f ≫ i) (g ≫ i) (𝟙 _) (𝟙 _) i (Category.id_comp _).symm (Category.id_comp _).symm
#align category_theory.limits.pullback.map_desc CategoryTheory.Limits.pullback.mapDesc
abbrev pushout.map {W X Y Z S T : C} (f₁ : S ⟶ W) (f₂ : S ⟶ X) [HasPushout f₁ f₂] (g₁ : T ⟶ Y)
(g₂ : T ⟶ Z) [HasPushout g₁ g₂] (i₁ : W ⟶ Y) (i₂ : X ⟶ Z) (i₃ : S ⟶ T) (eq₁ : f₁ ≫ i₁ = i₃ ≫ g₁)
(eq₂ : f₂ ≫ i₂ = i₃ ≫ g₂) : pushout f₁ f₂ ⟶ pushout g₁ g₂ :=
pushout.desc (i₁ ≫ pushout.inl) (i₂ ≫ pushout.inr)
(by
simp only [← Category.assoc, eq₁, eq₂]
simp [pushout.condition])
#align category_theory.limits.pushout.map CategoryTheory.Limits.pushout.map
abbrev pushout.mapLift {X Y S T : C} (f : T ⟶ X) (g : T ⟶ Y) (i : S ⟶ T) [HasPushout f g]
[HasPushout (i ≫ f) (i ≫ g)] : pushout (i ≫ f) (i ≫ g) ⟶ pushout f g :=
pushout.map (i ≫ f) (i ≫ g) f g (𝟙 _) (𝟙 _) i (Category.comp_id _) (Category.comp_id _)
#align category_theory.limits.pushout.map_lift CategoryTheory.Limits.pushout.mapLift
@[ext 1100]
theorem pullback.hom_ext {X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] {W : C}
{k l : W ⟶ pullback f g} (h₀ : k ≫ pullback.fst = l ≫ pullback.fst)
(h₁ : k ≫ pullback.snd = l ≫ pullback.snd) : k = l :=
limit.hom_ext <| PullbackCone.equalizer_ext _ h₀ h₁
#align category_theory.limits.pullback.hom_ext CategoryTheory.Limits.pullback.hom_ext
def pullbackIsPullback {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) [HasPullback f g] :
IsLimit (PullbackCone.mk (pullback.fst : pullback f g ⟶ _) pullback.snd pullback.condition) :=
PullbackCone.IsLimit.mk _ (fun s => pullback.lift s.fst s.snd s.condition) (by simp) (by simp)
(by aesop_cat)
#align category_theory.limits.pullback_is_pullback CategoryTheory.Limits.pullbackIsPullback
instance pullback.fst_of_mono {X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] [Mono g] :
Mono (pullback.fst : pullback f g ⟶ X) :=
PullbackCone.mono_fst_of_is_pullback_of_mono (limit.isLimit _)
#align category_theory.limits.pullback.fst_of_mono CategoryTheory.Limits.pullback.fst_of_mono
instance pullback.snd_of_mono {X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z} [HasPullback f g] [Mono f] :
Mono (pullback.snd : pullback f g ⟶ Y) :=
PullbackCone.mono_snd_of_is_pullback_of_mono (limit.isLimit _)
#align category_theory.limits.pullback.snd_of_mono CategoryTheory.Limits.pullback.snd_of_mono
instance mono_pullback_to_prod {C : Type*} [Category C] {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z)
[HasPullback f g] [HasBinaryProduct X Y] :
Mono (prod.lift pullback.fst pullback.snd : pullback f g ⟶ _) :=
⟨fun {W} i₁ i₂ h => by
ext
· simpa using congrArg (fun f => f ≫ prod.fst) h
· simpa using congrArg (fun f => f ≫ prod.snd) h⟩
#align category_theory.limits.mono_pullback_to_prod CategoryTheory.Limits.mono_pullback_to_prod
@[ext 1100]
theorem pushout.hom_ext {X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] {W : C}
{k l : pushout f g ⟶ W} (h₀ : pushout.inl ≫ k = pushout.inl ≫ l)
(h₁ : pushout.inr ≫ k = pushout.inr ≫ l) : k = l :=
colimit.hom_ext <| PushoutCocone.coequalizer_ext _ h₀ h₁
#align category_theory.limits.pushout.hom_ext CategoryTheory.Limits.pushout.hom_ext
def pushoutIsPushout {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) [HasPushout f g] :
IsColimit (PushoutCocone.mk (pushout.inl : _ ⟶ pushout f g) pushout.inr pushout.condition) :=
PushoutCocone.IsColimit.mk _ (fun s => pushout.desc s.inl s.inr s.condition) (by simp) (by simp)
(by aesop_cat)
#align category_theory.limits.pushout_is_pushout CategoryTheory.Limits.pushoutIsPushout
instance pushout.inl_of_epi {X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] [Epi g] :
Epi (pushout.inl : Y ⟶ pushout f g) :=
PushoutCocone.epi_inl_of_is_pushout_of_epi (colimit.isColimit _)
#align category_theory.limits.pushout.inl_of_epi CategoryTheory.Limits.pushout.inl_of_epi
instance pushout.inr_of_epi {X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z} [HasPushout f g] [Epi f] :
Epi (pushout.inr : Z ⟶ pushout f g) :=
PushoutCocone.epi_inr_of_is_pushout_of_epi (colimit.isColimit _)
#align category_theory.limits.pushout.inr_of_epi CategoryTheory.Limits.pushout.inr_of_epi
instance epi_coprod_to_pushout {C : Type*} [Category C] {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z)
[HasPushout f g] [HasBinaryCoproduct Y Z] :
Epi (coprod.desc pushout.inl pushout.inr : _ ⟶ pushout f g) :=
⟨fun {W} i₁ i₂ h => by
ext
· simpa using congrArg (fun f => coprod.inl ≫ f) h
· simpa using congrArg (fun f => coprod.inr ≫ f) h⟩
#align category_theory.limits.epi_coprod_to_pushout CategoryTheory.Limits.epi_coprod_to_pushout
instance pullback.map_isIso {W X Y Z S T : C} (f₁ : W ⟶ S) (f₂ : X ⟶ S) [HasPullback f₁ f₂]
(g₁ : Y ⟶ T) (g₂ : Z ⟶ T) [HasPullback g₁ g₂] (i₁ : W ⟶ Y) (i₂ : X ⟶ Z) (i₃ : S ⟶ T)
(eq₁ : f₁ ≫ i₃ = i₁ ≫ g₁) (eq₂ : f₂ ≫ i₃ = i₂ ≫ g₂) [IsIso i₁] [IsIso i₂] [IsIso i₃] :
IsIso (pullback.map f₁ f₂ g₁ g₂ i₁ i₂ i₃ eq₁ eq₂) := by
refine ⟨⟨pullback.map _ _ _ _ (inv i₁) (inv i₂) (inv i₃) ?_ ?_, ?_, ?_⟩⟩
· rw [IsIso.comp_inv_eq, Category.assoc, eq₁, IsIso.inv_hom_id_assoc]
· rw [IsIso.comp_inv_eq, Category.assoc, eq₂, IsIso.inv_hom_id_assoc]
· aesop_cat
· aesop_cat
#align category_theory.limits.pullback.map_is_iso CategoryTheory.Limits.pullback.map_isIso
@[simps! hom]
def pullback.congrHom {X Y Z : C} {f₁ f₂ : X ⟶ Z} {g₁ g₂ : Y ⟶ Z} (h₁ : f₁ = f₂) (h₂ : g₁ = g₂)
[HasPullback f₁ g₁] [HasPullback f₂ g₂] : pullback f₁ g₁ ≅ pullback f₂ g₂ :=
asIso <| pullback.map _ _ _ _ (𝟙 _) (𝟙 _) (𝟙 _) (by simp [h₁]) (by simp [h₂])
#align category_theory.limits.pullback.congr_hom CategoryTheory.Limits.pullback.congrHom
@[simp]
theorem pullback.congrHom_inv {X Y Z : C} {f₁ f₂ : X ⟶ Z} {g₁ g₂ : Y ⟶ Z} (h₁ : f₁ = f₂)
(h₂ : g₁ = g₂) [HasPullback f₁ g₁] [HasPullback f₂ g₂] :
(pullback.congrHom h₁ h₂).inv =
pullback.map _ _ _ _ (𝟙 _) (𝟙 _) (𝟙 _) (by simp [h₁]) (by simp [h₂]) := by
ext
· erw [pullback.lift_fst]
rw [Iso.inv_comp_eq]
erw [pullback.lift_fst_assoc]
rw [Category.comp_id, Category.comp_id]
· erw [pullback.lift_snd]
rw [Iso.inv_comp_eq]
erw [pullback.lift_snd_assoc]
rw [Category.comp_id, Category.comp_id]
#align category_theory.limits.pullback.congr_hom_inv CategoryTheory.Limits.pullback.congrHom_inv
instance pushout.map_isIso {W X Y Z S T : C} (f₁ : S ⟶ W) (f₂ : S ⟶ X) [HasPushout f₁ f₂]
(g₁ : T ⟶ Y) (g₂ : T ⟶ Z) [HasPushout g₁ g₂] (i₁ : W ⟶ Y) (i₂ : X ⟶ Z) (i₃ : S ⟶ T)
(eq₁ : f₁ ≫ i₁ = i₃ ≫ g₁) (eq₂ : f₂ ≫ i₂ = i₃ ≫ g₂) [IsIso i₁] [IsIso i₂] [IsIso i₃] :
IsIso (pushout.map f₁ f₂ g₁ g₂ i₁ i₂ i₃ eq₁ eq₂) := by
refine ⟨⟨pushout.map _ _ _ _ (inv i₁) (inv i₂) (inv i₃) ?_ ?_, ?_, ?_⟩⟩
· rw [IsIso.comp_inv_eq, Category.assoc, eq₁, IsIso.inv_hom_id_assoc]
· rw [IsIso.comp_inv_eq, Category.assoc, eq₂, IsIso.inv_hom_id_assoc]
· aesop_cat
· aesop_cat
#align category_theory.limits.pushout.map_is_iso CategoryTheory.Limits.pushout.map_isIso
theorem pullback.mapDesc_comp {X Y S T S' : C} (f : X ⟶ T) (g : Y ⟶ T) (i : T ⟶ S) (i' : S ⟶ S')
[HasPullback f g] [HasPullback (f ≫ i) (g ≫ i)] [HasPullback (f ≫ i ≫ i') (g ≫ i ≫ i')]
[HasPullback ((f ≫ i) ≫ i') ((g ≫ i) ≫ i')] :
pullback.mapDesc f g (i ≫ i') = pullback.mapDesc f g i ≫ pullback.mapDesc _ _ i' ≫
(pullback.congrHom (Category.assoc _ _ _) (Category.assoc _ _ _)).hom := by
aesop_cat
#align category_theory.limits.pullback.map_desc_comp CategoryTheory.Limits.pullback.mapDesc_comp
@[simps! hom]
def pushout.congrHom {X Y Z : C} {f₁ f₂ : X ⟶ Y} {g₁ g₂ : X ⟶ Z} (h₁ : f₁ = f₂) (h₂ : g₁ = g₂)
[HasPushout f₁ g₁] [HasPushout f₂ g₂] : pushout f₁ g₁ ≅ pushout f₂ g₂ :=
asIso <| pushout.map _ _ _ _ (𝟙 _) (𝟙 _) (𝟙 _) (by simp [h₁]) (by simp [h₂])
#align category_theory.limits.pushout.congr_hom CategoryTheory.Limits.pushout.congrHom
@[simp]
theorem pushout.congrHom_inv {X Y Z : C} {f₁ f₂ : X ⟶ Y} {g₁ g₂ : X ⟶ Z} (h₁ : f₁ = f₂)
(h₂ : g₁ = g₂) [HasPushout f₁ g₁] [HasPushout f₂ g₂] :
(pushout.congrHom h₁ h₂).inv =
pushout.map _ _ _ _ (𝟙 _) (𝟙 _) (𝟙 _) (by simp [h₁]) (by simp [h₂]) := by
ext
· erw [pushout.inl_desc]
rw [Iso.comp_inv_eq, Category.id_comp]
erw [pushout.inl_desc]
rw [Category.id_comp]
· erw [pushout.inr_desc]
rw [Iso.comp_inv_eq, Category.id_comp]
erw [pushout.inr_desc]
rw [Category.id_comp]
#align category_theory.limits.pushout.congr_hom_inv CategoryTheory.Limits.pushout.congrHom_inv
theorem pushout.mapLift_comp {X Y S T S' : C} (f : T ⟶ X) (g : T ⟶ Y) (i : S ⟶ T) (i' : S' ⟶ S)
[HasPushout f g] [HasPushout (i ≫ f) (i ≫ g)] [HasPushout (i' ≫ i ≫ f) (i' ≫ i ≫ g)]
[HasPushout ((i' ≫ i) ≫ f) ((i' ≫ i) ≫ g)] :
pushout.mapLift f g (i' ≫ i) =
(pushout.congrHom (Category.assoc _ _ _) (Category.assoc _ _ _)).hom ≫
pushout.mapLift _ _ i' ≫ pushout.mapLift f g i := by
aesop_cat
#align category_theory.limits.pushout.map_lift_comp CategoryTheory.Limits.pushout.mapLift_comp
section
variable (G : C ⥤ D)
def pullbackComparison (f : X ⟶ Z) (g : Y ⟶ Z) [HasPullback f g] [HasPullback (G.map f) (G.map g)] :
G.obj (pullback f g) ⟶ pullback (G.map f) (G.map g) :=
pullback.lift (G.map pullback.fst) (G.map pullback.snd)
(by simp only [← G.map_comp, pullback.condition])
#align category_theory.limits.pullback_comparison CategoryTheory.Limits.pullbackComparison
@[reassoc (attr := simp)]
theorem pullbackComparison_comp_fst (f : X ⟶ Z) (g : Y ⟶ Z) [HasPullback f g]
[HasPullback (G.map f) (G.map g)] :
pullbackComparison G f g ≫ pullback.fst = G.map pullback.fst :=
pullback.lift_fst _ _ _
#align category_theory.limits.pullback_comparison_comp_fst CategoryTheory.Limits.pullbackComparison_comp_fst
@[reassoc (attr := simp)]
theorem pullbackComparison_comp_snd (f : X ⟶ Z) (g : Y ⟶ Z) [HasPullback f g]
[HasPullback (G.map f) (G.map g)] :
pullbackComparison G f g ≫ pullback.snd = G.map pullback.snd :=
pullback.lift_snd _ _ _
#align category_theory.limits.pullback_comparison_comp_snd CategoryTheory.Limits.pullbackComparison_comp_snd
@[reassoc (attr := simp)]
theorem map_lift_pullbackComparison (f : X ⟶ Z) (g : Y ⟶ Z) [HasPullback f g]
[HasPullback (G.map f) (G.map g)] {W : C} {h : W ⟶ X} {k : W ⟶ Y} (w : h ≫ f = k ≫ g) :
G.map (pullback.lift _ _ w) ≫ pullbackComparison G f g =
pullback.lift (G.map h) (G.map k) (by simp only [← G.map_comp, w]) := by
ext <;> simp [← G.map_comp]
#align category_theory.limits.map_lift_pullback_comparison CategoryTheory.Limits.map_lift_pullbackComparison
def pushoutComparison (f : X ⟶ Y) (g : X ⟶ Z) [HasPushout f g] [HasPushout (G.map f) (G.map g)] :
pushout (G.map f) (G.map g) ⟶ G.obj (pushout f g) :=
pushout.desc (G.map pushout.inl) (G.map pushout.inr)
(by simp only [← G.map_comp, pushout.condition])
#align category_theory.limits.pushout_comparison CategoryTheory.Limits.pushoutComparison
@[reassoc (attr := simp)]
theorem inl_comp_pushoutComparison (f : X ⟶ Y) (g : X ⟶ Z) [HasPushout f g]
[HasPushout (G.map f) (G.map g)] : pushout.inl ≫ pushoutComparison G f g = G.map pushout.inl :=
pushout.inl_desc _ _ _
#align category_theory.limits.inl_comp_pushout_comparison CategoryTheory.Limits.inl_comp_pushoutComparison
@[reassoc (attr := simp)]
theorem inr_comp_pushoutComparison (f : X ⟶ Y) (g : X ⟶ Z) [HasPushout f g]
[HasPushout (G.map f) (G.map g)] : pushout.inr ≫ pushoutComparison G f g = G.map pushout.inr :=
pushout.inr_desc _ _ _
#align category_theory.limits.inr_comp_pushout_comparison CategoryTheory.Limits.inr_comp_pushoutComparison
@[reassoc (attr := simp)]
theorem pushoutComparison_map_desc (f : X ⟶ Y) (g : X ⟶ Z) [HasPushout f g]
[HasPushout (G.map f) (G.map g)] {W : C} {h : Y ⟶ W} {k : Z ⟶ W} (w : f ≫ h = g ≫ k) :
pushoutComparison G f g ≫ G.map (pushout.desc _ _ w) =
pushout.desc (G.map h) (G.map k) (by simp only [← G.map_comp, w]) := by
ext <;> simp [← G.map_comp]
#align category_theory.limits.pushout_comparison_map_desc CategoryTheory.Limits.pushoutComparison_map_desc
end
section
open WalkingCospan
variable (f : X ⟶ Y)
instance has_kernel_pair_of_mono [Mono f] : HasPullback f f :=
⟨⟨⟨_, PullbackCone.isLimitMkIdId f⟩⟩⟩
#align category_theory.limits.has_kernel_pair_of_mono CategoryTheory.Limits.has_kernel_pair_of_mono
theorem fst_eq_snd_of_mono_eq [Mono f] : (pullback.fst : pullback f f ⟶ _) = pullback.snd :=
((PullbackCone.isLimitMkIdId f).fac (getLimitCone (cospan f f)).cone left).symm.trans
((PullbackCone.isLimitMkIdId f).fac (getLimitCone (cospan f f)).cone right : _)
#align category_theory.limits.fst_eq_snd_of_mono_eq CategoryTheory.Limits.fst_eq_snd_of_mono_eq
@[simp]
theorem pullbackSymmetry_hom_of_mono_eq [Mono f] : (pullbackSymmetry f f).hom = 𝟙 _ := by
ext
· simp [fst_eq_snd_of_mono_eq]
· simp [fst_eq_snd_of_mono_eq]
#align category_theory.limits.pullback_symmetry_hom_of_mono_eq CategoryTheory.Limits.pullbackSymmetry_hom_of_mono_eq
instance fst_iso_of_mono_eq [Mono f] : IsIso (pullback.fst : pullback f f ⟶ _) := by
refine ⟨⟨pullback.lift (𝟙 _) (𝟙 _) (by simp), ?_, by simp⟩⟩
ext
· simp
· simp [fst_eq_snd_of_mono_eq]
#align category_theory.limits.fst_iso_of_mono_eq CategoryTheory.Limits.fst_iso_of_mono_eq
instance snd_iso_of_mono_eq [Mono f] : IsIso (pullback.snd : pullback f f ⟶ _) := by
rw [← fst_eq_snd_of_mono_eq]
infer_instance
#align category_theory.limits.snd_iso_of_mono_eq CategoryTheory.Limits.snd_iso_of_mono_eq
end
section
open WalkingSpan
variable (f : X ⟶ Y)
instance has_cokernel_pair_of_epi [Epi f] : HasPushout f f :=
⟨⟨⟨_, PushoutCocone.isColimitMkIdId f⟩⟩⟩
#align category_theory.limits.has_cokernel_pair_of_epi CategoryTheory.Limits.has_cokernel_pair_of_epi
theorem inl_eq_inr_of_epi_eq [Epi f] : (pushout.inl : _ ⟶ pushout f f) = pushout.inr :=
((PushoutCocone.isColimitMkIdId f).fac (getColimitCocone (span f f)).cocone left).symm.trans
((PushoutCocone.isColimitMkIdId f).fac (getColimitCocone (span f f)).cocone right : _)
#align category_theory.limits.inl_eq_inr_of_epi_eq CategoryTheory.Limits.inl_eq_inr_of_epi_eq
@[simp]
theorem pullback_symmetry_hom_of_epi_eq [Epi f] : (pushoutSymmetry f f).hom = 𝟙 _ := by
ext <;> simp [inl_eq_inr_of_epi_eq]
#align category_theory.limits.pullback_symmetry_hom_of_epi_eq CategoryTheory.Limits.pullback_symmetry_hom_of_epi_eq
instance inl_iso_of_epi_eq [Epi f] : IsIso (pushout.inl : _ ⟶ pushout f f) := by
refine ⟨⟨pushout.desc (𝟙 _) (𝟙 _) (by simp), by simp, ?_⟩⟩
apply pushout.hom_ext
· simp
· simp [inl_eq_inr_of_epi_eq]
#align category_theory.limits.inl_iso_of_epi_eq CategoryTheory.Limits.inl_iso_of_epi_eq
instance inr_iso_of_epi_eq [Epi f] : IsIso (pushout.inr : _ ⟶ pushout f f) := by
rw [← inl_eq_inr_of_epi_eq]
infer_instance
#align category_theory.limits.inr_iso_of_epi_eq CategoryTheory.Limits.inr_iso_of_epi_eq
end
section
variable (f : X ⟶ Z) (g : Y ⟶ Z) (f' : W ⟶ X)
variable [HasPullback f g] [HasPullback f' (pullback.fst : pullback f g ⟶ _)]
variable [HasPullback (f' ≫ f) g]
noncomputable def pullbackRightPullbackFstIso :
pullback f' (pullback.fst : pullback f g ⟶ _) ≅ pullback (f' ≫ f) g := by
let this :=
bigSquareIsPullback (pullback.snd : pullback f' (pullback.fst : pullback f g ⟶ _) ⟶ _)
pullback.snd f' f pullback.fst pullback.fst g pullback.condition pullback.condition
(pullbackIsPullback _ _) (pullbackIsPullback _ _)
exact (this.conePointUniqueUpToIso (pullbackIsPullback _ _) : _)
#align category_theory.limits.pullback_right_pullback_fst_iso CategoryTheory.Limits.pullbackRightPullbackFstIso
@[reassoc (attr := simp)]
theorem pullbackRightPullbackFstIso_hom_fst :
(pullbackRightPullbackFstIso f g f').hom ≫ pullback.fst = pullback.fst :=
IsLimit.conePointUniqueUpToIso_hom_comp _ _ WalkingCospan.left
#align category_theory.limits.pullback_right_pullback_fst_iso_hom_fst CategoryTheory.Limits.pullbackRightPullbackFstIso_hom_fst
@[reassoc (attr := simp)]
theorem pullbackRightPullbackFstIso_hom_snd :
(pullbackRightPullbackFstIso f g f').hom ≫ pullback.snd = pullback.snd ≫ pullback.snd :=
IsLimit.conePointUniqueUpToIso_hom_comp _ _ WalkingCospan.right
#align category_theory.limits.pullback_right_pullback_fst_iso_hom_snd CategoryTheory.Limits.pullbackRightPullbackFstIso_hom_snd
@[reassoc (attr := simp)]
theorem pullbackRightPullbackFstIso_inv_fst :
(pullbackRightPullbackFstIso f g f').inv ≫ pullback.fst = pullback.fst :=
IsLimit.conePointUniqueUpToIso_inv_comp _ _ WalkingCospan.left
#align category_theory.limits.pullback_right_pullback_fst_iso_inv_fst CategoryTheory.Limits.pullbackRightPullbackFstIso_inv_fst
@[reassoc (attr := simp)]
theorem pullbackRightPullbackFstIso_inv_snd_snd :
(pullbackRightPullbackFstIso f g f').inv ≫ pullback.snd ≫ pullback.snd = pullback.snd :=
IsLimit.conePointUniqueUpToIso_inv_comp _ _ WalkingCospan.right
#align category_theory.limits.pullback_right_pullback_fst_iso_inv_snd_snd CategoryTheory.Limits.pullbackRightPullbackFstIso_inv_snd_snd
@[reassoc (attr := simp)]
theorem pullbackRightPullbackFstIso_inv_snd_fst :
(pullbackRightPullbackFstIso f g f').inv ≫ pullback.snd ≫ pullback.fst = pullback.fst ≫ f' := by
rw [← pullback.condition]
exact pullbackRightPullbackFstIso_inv_fst_assoc _ _ _ _
#align category_theory.limits.pullback_right_pullback_fst_iso_inv_snd_fst CategoryTheory.Limits.pullbackRightPullbackFstIso_inv_snd_fst
end
section
variable (f : X ⟶ Y) (g : X ⟶ Z) (g' : Z ⟶ W)
variable [HasPushout f g] [HasPushout (pushout.inr : _ ⟶ pushout f g) g']
variable [HasPushout f (g ≫ g')]
noncomputable def pushoutLeftPushoutInrIso :
pushout (pushout.inr : _ ⟶ pushout f g) g' ≅ pushout f (g ≫ g') :=
((bigSquareIsPushout g g' _ _ f _ _ pushout.condition pushout.condition (pushoutIsPushout _ _)
(pushoutIsPushout _ _)).coconePointUniqueUpToIso
(pushoutIsPushout _ _) :
_)
#align category_theory.limits.pushout_left_pushout_inr_iso CategoryTheory.Limits.pushoutLeftPushoutInrIso
@[reassoc (attr := simp)]
theorem inl_pushoutLeftPushoutInrIso_inv :
pushout.inl ≫ (pushoutLeftPushoutInrIso f g g').inv = pushout.inl ≫ pushout.inl :=
((bigSquareIsPushout g g' _ _ f _ _ pushout.condition pushout.condition (pushoutIsPushout _ _)
(pushoutIsPushout _ _)).comp_coconePointUniqueUpToIso_inv
(pushoutIsPushout _ _) WalkingSpan.left :
_)
#align category_theory.limits.inl_pushout_left_pushout_inr_iso_inv CategoryTheory.Limits.inl_pushoutLeftPushoutInrIso_inv
@[reassoc (attr := simp)]
theorem inr_pushoutLeftPushoutInrIso_hom :
pushout.inr ≫ (pushoutLeftPushoutInrIso f g g').hom = pushout.inr :=
((bigSquareIsPushout g g' _ _ f _ _ pushout.condition pushout.condition (pushoutIsPushout _ _)
(pushoutIsPushout _ _)).comp_coconePointUniqueUpToIso_hom
(pushoutIsPushout _ _) WalkingSpan.right :
_)
#align category_theory.limits.inr_pushout_left_pushout_inr_iso_hom CategoryTheory.Limits.inr_pushoutLeftPushoutInrIso_hom
@[reassoc (attr := simp)]
theorem inr_pushoutLeftPushoutInrIso_inv :
pushout.inr ≫ (pushoutLeftPushoutInrIso f g g').inv = pushout.inr := by
rw [Iso.comp_inv_eq, inr_pushoutLeftPushoutInrIso_hom]
#align category_theory.limits.inr_pushout_left_pushout_inr_iso_inv CategoryTheory.Limits.inr_pushoutLeftPushoutInrIso_inv
@[reassoc (attr := simp)]
theorem inl_inl_pushoutLeftPushoutInrIso_hom :
pushout.inl ≫ pushout.inl ≫ (pushoutLeftPushoutInrIso f g g').hom = pushout.inl := by
rw [← Category.assoc, ← Iso.eq_comp_inv, inl_pushoutLeftPushoutInrIso_inv]
#align category_theory.limits.inl_inl_pushout_left_pushout_inr_iso_hom CategoryTheory.Limits.inl_inl_pushoutLeftPushoutInrIso_hom
@[reassoc (attr := simp)]
theorem inr_inl_pushoutLeftPushoutInrIso_hom :
pushout.inr ≫ pushout.inl ≫ (pushoutLeftPushoutInrIso f g g').hom = g' ≫ pushout.inr := by
rw [← Category.assoc, ← Iso.eq_comp_inv, Category.assoc, inr_pushoutLeftPushoutInrIso_inv,
pushout.condition]
#align category_theory.limits.inr_inl_pushout_left_pushout_inr_iso_hom CategoryTheory.Limits.inr_inl_pushoutLeftPushoutInrIso_hom
end
section PullbackAssoc
variable {X₁ X₂ X₃ Y₁ Y₂ : C} (f₁ : X₁ ⟶ Y₁) (f₂ : X₂ ⟶ Y₁) (f₃ : X₂ ⟶ Y₂)
variable (f₄ : X₃ ⟶ Y₂) [HasPullback f₁ f₂] [HasPullback f₃ f₄]
local notation "Z₁" => pullback f₁ f₂
local notation "Z₂" => pullback f₃ f₄
local notation "g₁" => (pullback.fst : Z₁ ⟶ X₁)
local notation "g₂" => (pullback.snd : Z₁ ⟶ X₂)
local notation "g₃" => (pullback.fst : Z₂ ⟶ X₂)
local notation "g₄" => (pullback.snd : Z₂ ⟶ X₃)
local notation "W" => pullback (g₂ ≫ f₃) f₄
local notation "W'" => pullback f₁ (g₃ ≫ f₂)
local notation "l₁" => (pullback.fst : W ⟶ Z₁)
local notation "l₂" =>
(pullback.lift (pullback.fst ≫ g₂) pullback.snd
(Eq.trans (Category.assoc _ _ _) pullback.condition) :
W ⟶ Z₂)
local notation "l₁'" =>
(pullback.lift pullback.fst (pullback.snd ≫ g₃)
(pullback.condition.trans (Eq.symm (Category.assoc _ _ _))) :
W' ⟶ Z₁)
local notation "l₂'" => (pullback.snd : W' ⟶ Z₂)
def pullbackPullbackLeftIsPullback [HasPullback (g₂ ≫ f₃) f₄] : IsLimit (PullbackCone.mk l₁ l₂
(show l₁ ≫ g₂ = l₂ ≫ g₃ from (pullback.lift_fst _ _ _).symm)) := by
apply leftSquareIsPullback
· exact pullbackIsPullback f₃ f₄
convert pullbackIsPullback (g₂ ≫ f₃) f₄
rw [pullback.lift_snd]
#align category_theory.limits.pullback_pullback_left_is_pullback CategoryTheory.Limits.pullbackPullbackLeftIsPullback
def pullbackAssocIsPullback [HasPullback (g₂ ≫ f₃) f₄] :
IsLimit
(PullbackCone.mk (l₁ ≫ g₁) l₂
(show (l₁ ≫ g₁) ≫ f₁ = l₂ ≫ g₃ ≫ f₂ by
rw [pullback.lift_fst_assoc, Category.assoc, Category.assoc, pullback.condition])) := by
apply PullbackCone.isLimitOfFlip
apply bigSquareIsPullback
· apply PullbackCone.isLimitOfFlip
exact pullbackIsPullback f₁ f₂
· apply PullbackCone.isLimitOfFlip
apply pullbackPullbackLeftIsPullback
· exact pullback.lift_fst _ _ _
· exact pullback.condition.symm
#align category_theory.limits.pullback_assoc_is_pullback CategoryTheory.Limits.pullbackAssocIsPullback
theorem hasPullback_assoc [HasPullback (g₂ ≫ f₃) f₄] : HasPullback f₁ (g₃ ≫ f₂) :=
⟨⟨⟨_, pullbackAssocIsPullback f₁ f₂ f₃ f₄⟩⟩⟩
#align category_theory.limits.has_pullback_assoc CategoryTheory.Limits.hasPullback_assoc
def pullbackPullbackRightIsPullback [HasPullback f₁ (g₃ ≫ f₂)] :
IsLimit (PullbackCone.mk l₁' l₂' (show l₁' ≫ g₂ = l₂' ≫ g₃ from pullback.lift_snd _ _ _)) := by
apply PullbackCone.isLimitOfFlip
apply leftSquareIsPullback
· apply PullbackCone.isLimitOfFlip
exact pullbackIsPullback f₁ f₂
· apply PullbackCone.isLimitOfFlip
exact IsLimit.ofIsoLimit (pullbackIsPullback f₁ (g₃ ≫ f₂))
(PullbackCone.ext (Iso.refl _) (by simp) (by simp))
· exact pullback.condition.symm
#align category_theory.limits.pullback_pullback_right_is_pullback CategoryTheory.Limits.pullbackPullbackRightIsPullback
def pullbackAssocSymmIsPullback [HasPullback f₁ (g₃ ≫ f₂)] :
IsLimit
(PullbackCone.mk l₁' (l₂' ≫ g₄)
(show l₁' ≫ g₂ ≫ f₃ = (l₂' ≫ g₄) ≫ f₄ by
rw [pullback.lift_snd_assoc, Category.assoc, Category.assoc, pullback.condition])) := by
apply bigSquareIsPullback
· exact pullbackIsPullback f₃ f₄
· apply pullbackPullbackRightIsPullback
#align category_theory.limits.pullback_assoc_symm_is_pullback CategoryTheory.Limits.pullbackAssocSymmIsPullback
theorem hasPullback_assoc_symm [HasPullback f₁ (g₃ ≫ f₂)] : HasPullback (g₂ ≫ f₃) f₄ :=
⟨⟨⟨_, pullbackAssocSymmIsPullback f₁ f₂ f₃ f₄⟩⟩⟩
#align category_theory.limits.has_pullback_assoc_symm CategoryTheory.Limits.hasPullback_assoc_symm
variable [HasPullback (g₂ ≫ f₃) f₄] [HasPullback f₁ ((pullback.fst : Z₂ ⟶ X₂) ≫ f₂)]
noncomputable def pullbackAssoc [HasPullback ((pullback.snd : Z₁ ⟶ X₂) ≫ f₃) f₄]
[HasPullback f₁ ((pullback.fst : Z₂ ⟶ X₂) ≫ f₂)] :
pullback (pullback.snd ≫ f₃ : pullback f₁ f₂ ⟶ _) f₄ ≅
pullback f₁ (pullback.fst ≫ f₂ : pullback f₃ f₄ ⟶ _) :=
(pullbackPullbackLeftIsPullback f₁ f₂ f₃ f₄).conePointUniqueUpToIso
(pullbackPullbackRightIsPullback f₁ f₂ f₃ f₄)
#align category_theory.limits.pullback_assoc CategoryTheory.Limits.pullbackAssoc
@[reassoc (attr := simp)]
| Mathlib/CategoryTheory/Limits/Shapes/Pullbacks.lean | 2,424 | 2,431 | theorem pullbackAssoc_inv_fst_fst [HasPullback ((pullback.snd : Z₁ ⟶ X₂) ≫ f₃) f₄]
[HasPullback f₁ ((pullback.fst : Z₂ ⟶ X₂) ≫ f₂)] :
(pullbackAssoc f₁ f₂ f₃ f₄).inv ≫ pullback.fst ≫ pullback.fst = pullback.fst := by |
trans l₁' ≫ pullback.fst
· rw [← Category.assoc]
congr 1
exact IsLimit.conePointUniqueUpToIso_inv_comp _ _ WalkingCospan.left
· exact pullback.lift_fst _ _ _
|
import Mathlib.Algebra.Group.Support
import Mathlib.Order.WellFoundedSet
#align_import ring_theory.hahn_series from "leanprover-community/mathlib"@"a484a7d0eade4e1268f4fb402859b6686037f965"
set_option linter.uppercaseLean3 false
open Finset Function
open scoped Classical
noncomputable section
@[ext]
structure HahnSeries (Γ : Type*) (R : Type*) [PartialOrder Γ] [Zero R] where
coeff : Γ → R
isPWO_support' : (Function.support coeff).IsPWO
#align hahn_series HahnSeries
variable {Γ : Type*} {R : Type*}
namespace HahnSeries
section Zero
variable [PartialOrder Γ] [Zero R]
theorem coeff_injective : Injective (coeff : HahnSeries Γ R → Γ → R) :=
HahnSeries.ext
#align hahn_series.coeff_injective HahnSeries.coeff_injective
@[simp]
theorem coeff_inj {x y : HahnSeries Γ R} : x.coeff = y.coeff ↔ x = y :=
coeff_injective.eq_iff
#align hahn_series.coeff_inj HahnSeries.coeff_inj
nonrec def support (x : HahnSeries Γ R) : Set Γ :=
support x.coeff
#align hahn_series.support HahnSeries.support
@[simp]
theorem isPWO_support (x : HahnSeries Γ R) : x.support.IsPWO :=
x.isPWO_support'
#align hahn_series.is_pwo_support HahnSeries.isPWO_support
@[simp]
theorem isWF_support (x : HahnSeries Γ R) : x.support.IsWF :=
x.isPWO_support.isWF
#align hahn_series.is_wf_support HahnSeries.isWF_support
@[simp]
theorem mem_support (x : HahnSeries Γ R) (a : Γ) : a ∈ x.support ↔ x.coeff a ≠ 0 :=
Iff.refl _
#align hahn_series.mem_support HahnSeries.mem_support
instance : Zero (HahnSeries Γ R) :=
⟨{ coeff := 0
isPWO_support' := by simp }⟩
instance : Inhabited (HahnSeries Γ R) :=
⟨0⟩
instance [Subsingleton R] : Subsingleton (HahnSeries Γ R) :=
⟨fun a b => a.ext b (Subsingleton.elim _ _)⟩
@[simp]
theorem zero_coeff {a : Γ} : (0 : HahnSeries Γ R).coeff a = 0 :=
rfl
#align hahn_series.zero_coeff HahnSeries.zero_coeff
@[simp]
theorem coeff_fun_eq_zero_iff {x : HahnSeries Γ R} : x.coeff = 0 ↔ x = 0 :=
coeff_injective.eq_iff' rfl
#align hahn_series.coeff_fun_eq_zero_iff HahnSeries.coeff_fun_eq_zero_iff
theorem ne_zero_of_coeff_ne_zero {x : HahnSeries Γ R} {g : Γ} (h : x.coeff g ≠ 0) : x ≠ 0 :=
mt (fun x0 => (x0.symm ▸ zero_coeff : x.coeff g = 0)) h
#align hahn_series.ne_zero_of_coeff_ne_zero HahnSeries.ne_zero_of_coeff_ne_zero
@[simp]
theorem support_zero : support (0 : HahnSeries Γ R) = ∅ :=
Function.support_zero
#align hahn_series.support_zero HahnSeries.support_zero
@[simp]
nonrec theorem support_nonempty_iff {x : HahnSeries Γ R} : x.support.Nonempty ↔ x ≠ 0 := by
rw [support, support_nonempty_iff, Ne, coeff_fun_eq_zero_iff]
#align hahn_series.support_nonempty_iff HahnSeries.support_nonempty_iff
@[simp]
theorem support_eq_empty_iff {x : HahnSeries Γ R} : x.support = ∅ ↔ x = 0 :=
support_eq_empty_iff.trans coeff_fun_eq_zero_iff
#align hahn_series.support_eq_empty_iff HahnSeries.support_eq_empty_iff
def ofIterate {Γ' : Type*} [PartialOrder Γ'] (x : HahnSeries Γ (HahnSeries Γ' R)) :
HahnSeries (Γ ×ₗ Γ') R where
coeff := fun g => coeff (coeff x g.1) g.2
isPWO_support' := by
refine Set.PartiallyWellOrderedOn.subsetProdLex ?_ ?_
· refine Set.IsPWO.mono x.isPWO_support' ?_
simp_rw [Set.image_subset_iff, support_subset_iff, Set.mem_preimage, Function.mem_support]
exact fun _ ↦ ne_zero_of_coeff_ne_zero
· exact fun a => by simpa [Function.mem_support, ne_eq] using (x.coeff a).isPWO_support'
@[simp]
lemma mk_eq_zero (f : Γ → R) (h) : HahnSeries.mk f h = 0 ↔ f = 0 := by
rw [HahnSeries.ext_iff]
rfl
def toIterate {Γ' : Type*} [PartialOrder Γ'] (x : HahnSeries (Γ ×ₗ Γ') R) :
HahnSeries Γ (HahnSeries Γ' R) where
coeff := fun g => {
coeff := fun g' => coeff x (g, g')
isPWO_support' := Set.PartiallyWellOrderedOn.fiberProdLex x.isPWO_support' g
}
isPWO_support' := by
have h₁ : (Function.support fun g => HahnSeries.mk (fun g' => x.coeff (g, g'))
(Set.PartiallyWellOrderedOn.fiberProdLex x.isPWO_support' g)) = Function.support
fun g => fun g' => x.coeff (g, g') := by
simp only [Function.support, ne_eq, mk_eq_zero]
rw [h₁, Function.support_curry' x.coeff]
exact Set.PartiallyWellOrderedOn.imageProdLex x.isPWO_support'
@[simps]
def iterateEquiv {Γ' : Type*} [PartialOrder Γ'] :
HahnSeries Γ (HahnSeries Γ' R) ≃ HahnSeries (Γ ×ₗ Γ') R where
toFun := ofIterate
invFun := toIterate
left_inv := congrFun rfl
right_inv := congrFun rfl
def single (a : Γ) : ZeroHom R (HahnSeries Γ R) where
toFun r :=
{ coeff := Pi.single a r
isPWO_support' := (Set.isPWO_singleton a).mono Pi.support_single_subset }
map_zero' := HahnSeries.ext _ _ (Pi.single_zero _)
#align hahn_series.single HahnSeries.single
variable {a b : Γ} {r : R}
@[simp]
theorem single_coeff_same (a : Γ) (r : R) : (single a r).coeff a = r :=
Pi.single_eq_same (f := fun _ => R) a r
#align hahn_series.single_coeff_same HahnSeries.single_coeff_same
@[simp]
theorem single_coeff_of_ne (h : b ≠ a) : (single a r).coeff b = 0 :=
Pi.single_eq_of_ne (f := fun _ => R) h r
#align hahn_series.single_coeff_of_ne HahnSeries.single_coeff_of_ne
theorem single_coeff : (single a r).coeff b = if b = a then r else 0 := by
split_ifs with h <;> simp [h]
#align hahn_series.single_coeff HahnSeries.single_coeff
@[simp]
theorem support_single_of_ne (h : r ≠ 0) : support (single a r) = {a} :=
Pi.support_single_of_ne h
#align hahn_series.support_single_of_ne HahnSeries.support_single_of_ne
theorem support_single_subset : support (single a r) ⊆ {a} :=
Pi.support_single_subset
#align hahn_series.support_single_subset HahnSeries.support_single_subset
theorem eq_of_mem_support_single {b : Γ} (h : b ∈ support (single a r)) : b = a :=
support_single_subset h
#align hahn_series.eq_of_mem_support_single HahnSeries.eq_of_mem_support_single
--@[simp] Porting note (#10618): simp can prove it
theorem single_eq_zero : single a (0 : R) = 0 :=
(single a).map_zero
#align hahn_series.single_eq_zero HahnSeries.single_eq_zero
theorem single_injective (a : Γ) : Function.Injective (single a : R → HahnSeries Γ R) :=
fun r s rs => by rw [← single_coeff_same a r, ← single_coeff_same a s, rs]
#align hahn_series.single_injective HahnSeries.single_injective
theorem single_ne_zero (h : r ≠ 0) : single a r ≠ 0 := fun con =>
h (single_injective a (con.trans single_eq_zero.symm))
#align hahn_series.single_ne_zero HahnSeries.single_ne_zero
@[simp]
theorem single_eq_zero_iff {a : Γ} {r : R} : single a r = 0 ↔ r = 0 :=
map_eq_zero_iff _ <| single_injective a
#align hahn_series.single_eq_zero_iff HahnSeries.single_eq_zero_iff
instance [Nonempty Γ] [Nontrivial R] : Nontrivial (HahnSeries Γ R) :=
⟨by
obtain ⟨r, s, rs⟩ := exists_pair_ne R
inhabit Γ
refine ⟨single default r, single default s, fun con => rs ?_⟩
rw [← single_coeff_same (default : Γ) r, con, single_coeff_same]⟩
section Order
def orderTop (x : HahnSeries Γ R) : WithTop Γ :=
if h : x = 0 then ⊤ else x.isWF_support.min (support_nonempty_iff.2 h)
@[simp]
theorem orderTop_zero : orderTop (0 : HahnSeries Γ R) = ⊤ :=
dif_pos rfl
theorem orderTop_of_ne {x : HahnSeries Γ R} (hx : x ≠ 0) :
orderTop x = x.isWF_support.min (support_nonempty_iff.2 hx) :=
dif_neg hx
@[simp]
theorem ne_zero_iff_orderTop {x : HahnSeries Γ R} : x ≠ 0 ↔ orderTop x ≠ ⊤ := by
constructor
· exact fun hx => Eq.mpr (congrArg (fun h ↦ h ≠ ⊤) (orderTop_of_ne hx)) WithTop.coe_ne_top
· contrapose!
simp_all only [orderTop_zero, implies_true]
theorem orderTop_eq_top_iff {x : HahnSeries Γ R} : orderTop x = ⊤ ↔ x = 0 := by
constructor
· contrapose!
exact ne_zero_iff_orderTop.mp
· simp_all only [orderTop_zero, implies_true]
theorem untop_orderTop_of_ne_zero {x : HahnSeries Γ R} (hx : x ≠ 0) :
WithTop.untop x.orderTop (ne_zero_iff_orderTop.mp hx) =
x.isWF_support.min (support_nonempty_iff.2 hx) :=
WithTop.coe_inj.mp ((WithTop.coe_untop (orderTop x) (ne_zero_iff_orderTop.mp hx)).trans
(orderTop_of_ne hx))
theorem coeff_orderTop_ne {x : HahnSeries Γ R} {g : Γ} (hg : x.orderTop = g) :
x.coeff g ≠ 0 := by
have h : orderTop x ≠ ⊤ := by simp_all only [ne_eq, WithTop.coe_ne_top, not_false_eq_true]
have hx : x ≠ 0 := ne_zero_iff_orderTop.mpr h
rw [orderTop_of_ne hx, WithTop.coe_eq_coe] at hg
rw [← hg]
exact x.isWF_support.min_mem (support_nonempty_iff.2 hx)
theorem orderTop_le_of_coeff_ne_zero {Γ} [LinearOrder Γ] {x : HahnSeries Γ R}
{g : Γ} (h : x.coeff g ≠ 0) : x.orderTop ≤ g := by
rw [orderTop_of_ne (ne_zero_of_coeff_ne_zero h), WithTop.coe_le_coe]
exact Set.IsWF.min_le _ _ ((mem_support _ _).2 h)
@[simp]
theorem orderTop_single (h : r ≠ 0) : (single a r).orderTop = a :=
(orderTop_of_ne (single_ne_zero h)).trans
(WithTop.coe_inj.mpr (support_single_subset
((single a r).isWF_support.min_mem (support_nonempty_iff.2 (single_ne_zero h)))))
| Mathlib/RingTheory/HahnSeries/Basic.lean | 283 | 290 | theorem coeff_eq_zero_of_lt_orderTop {x : HahnSeries Γ R} {i : Γ} (hi : i < x.orderTop) :
x.coeff i = 0 := by |
rcases eq_or_ne x 0 with (rfl | hx)
· exact zero_coeff
contrapose! hi
rw [← mem_support] at hi
rw [orderTop_of_ne hx, WithTop.coe_lt_coe]
exact Set.IsWF.not_lt_min _ _ hi
|
import Mathlib.MeasureTheory.PiSystem
import Mathlib.Order.OmegaCompletePartialOrder
import Mathlib.Topology.Constructions
import Mathlib.MeasureTheory.MeasurableSpace.Basic
open Set
namespace MeasureTheory
variable {ι : Type _} {α : ι → Type _}
section cylinder
def cylinder (s : Finset ι) (S : Set (∀ i : s, α i)) : Set (∀ i, α i) :=
(fun (f : ∀ i, α i) (i : s) ↦ f i) ⁻¹' S
@[simp]
theorem mem_cylinder (s : Finset ι) (S : Set (∀ i : s, α i)) (f : ∀ i, α i) :
f ∈ cylinder s S ↔ (fun i : s ↦ f i) ∈ S :=
mem_preimage
@[simp]
theorem cylinder_empty (s : Finset ι) : cylinder s (∅ : Set (∀ i : s, α i)) = ∅ := by
rw [cylinder, preimage_empty]
@[simp]
theorem cylinder_univ (s : Finset ι) : cylinder s (univ : Set (∀ i : s, α i)) = univ := by
rw [cylinder, preimage_univ]
@[simp]
theorem cylinder_eq_empty_iff [h_nonempty : Nonempty (∀ i, α i)] (s : Finset ι)
(S : Set (∀ i : s, α i)) :
cylinder s S = ∅ ↔ S = ∅ := by
refine ⟨fun h ↦ ?_, fun h ↦ by (rw [h]; exact cylinder_empty _)⟩
by_contra hS
rw [← Ne, ← nonempty_iff_ne_empty] at hS
let f := hS.some
have hf : f ∈ S := hS.choose_spec
classical
let f' : ∀ i, α i := fun i ↦ if hi : i ∈ s then f ⟨i, hi⟩ else h_nonempty.some i
have hf' : f' ∈ cylinder s S := by
rw [mem_cylinder]
simpa only [f', Finset.coe_mem, dif_pos]
rw [h] at hf'
exact not_mem_empty _ hf'
theorem inter_cylinder (s₁ s₂ : Finset ι) (S₁ : Set (∀ i : s₁, α i)) (S₂ : Set (∀ i : s₂, α i))
[DecidableEq ι] :
cylinder s₁ S₁ ∩ cylinder s₂ S₂ =
cylinder (s₁ ∪ s₂)
((fun f ↦ fun j : s₁ ↦ f ⟨j, Finset.mem_union_left s₂ j.prop⟩) ⁻¹' S₁ ∩
(fun f ↦ fun j : s₂ ↦ f ⟨j, Finset.mem_union_right s₁ j.prop⟩) ⁻¹' S₂) := by
ext1 f; simp only [mem_inter_iff, mem_cylinder, mem_setOf_eq]; rfl
theorem inter_cylinder_same (s : Finset ι) (S₁ : Set (∀ i : s, α i)) (S₂ : Set (∀ i : s, α i)) :
cylinder s S₁ ∩ cylinder s S₂ = cylinder s (S₁ ∩ S₂) := by
classical rw [inter_cylinder]; rfl
theorem union_cylinder (s₁ s₂ : Finset ι) (S₁ : Set (∀ i : s₁, α i)) (S₂ : Set (∀ i : s₂, α i))
[DecidableEq ι] :
cylinder s₁ S₁ ∪ cylinder s₂ S₂ =
cylinder (s₁ ∪ s₂)
((fun f ↦ fun j : s₁ ↦ f ⟨j, Finset.mem_union_left s₂ j.prop⟩) ⁻¹' S₁ ∪
(fun f ↦ fun j : s₂ ↦ f ⟨j, Finset.mem_union_right s₁ j.prop⟩) ⁻¹' S₂) := by
ext1 f; simp only [mem_union, mem_cylinder, mem_setOf_eq]; rfl
theorem union_cylinder_same (s : Finset ι) (S₁ : Set (∀ i : s, α i)) (S₂ : Set (∀ i : s, α i)) :
cylinder s S₁ ∪ cylinder s S₂ = cylinder s (S₁ ∪ S₂) := by
classical rw [union_cylinder]; rfl
theorem compl_cylinder (s : Finset ι) (S : Set (∀ i : s, α i)) :
(cylinder s S)ᶜ = cylinder s (Sᶜ) := by
ext1 f; simp only [mem_compl_iff, mem_cylinder]
| Mathlib/MeasureTheory/Constructions/Cylinders.lean | 213 | 215 | theorem diff_cylinder_same (s : Finset ι) (S T : Set (∀ i : s, α i)) :
cylinder s S \ cylinder s T = cylinder s (S \ T) := by |
ext1 f; simp only [mem_diff, mem_cylinder]
|
import Mathlib.CategoryTheory.MorphismProperty.Composition
import Mathlib.CategoryTheory.MorphismProperty.IsInvertedBy
import Mathlib.CategoryTheory.Category.Quiv
#align_import category_theory.localization.construction from "leanprover-community/mathlib"@"1a5e56f2166e4e9d0964c71f4273b1d39227678d"
noncomputable section
open CategoryTheory.Category
namespace CategoryTheory
-- category universes first for convenience
universe uC' uD' uC uD
variable {C : Type uC} [Category.{uC'} C] (W : MorphismProperty C) {D : Type uD} [Category.{uD'} D]
namespace Localization
namespace Localization
namespace Construction
variable {W}
def wIso {X Y : C} (w : X ⟶ Y) (hw : W w) : Iso (W.Q.obj X) (W.Q.obj Y) where
hom := W.Q.map w
inv := (Quotient.functor _).map (by dsimp; exact Paths.of.map (Sum.inr ⟨w, hw⟩))
hom_inv_id := Quotient.sound _ (relations.Winv₁ w hw)
inv_hom_id := Quotient.sound _ (relations.Winv₂ w hw)
set_option linter.uppercaseLean3 false in
#align category_theory.localization.construction.Wiso CategoryTheory.Localization.Construction.wIso
abbrev winv {X Y : C} (w : X ⟶ Y) (hw : W w) :=
(wIso w hw).inv
set_option linter.uppercaseLean3 false in
#align category_theory.localization.construction.Winv CategoryTheory.Localization.Construction.winv
variable (W)
theorem _root_.CategoryTheory.MorphismProperty.Q_inverts : W.IsInvertedBy W.Q := fun _ _ w hw =>
(Localization.Construction.wIso w hw).isIso_hom
set_option linter.uppercaseLean3 false in
#align category_theory.morphism_property.Q_inverts CategoryTheory.MorphismProperty.Q_inverts
variable {W} (G : C ⥤ D) (hG : W.IsInvertedBy G)
@[simps!]
def liftToPathCategory : Paths (LocQuiver W) ⥤ D :=
Quiv.lift
{ obj := fun X => G.obj X.obj
map := by
intros X Y
rintro (f | ⟨g, hg⟩)
· exact G.map f
· haveI := hG g hg
exact inv (G.map g) }
#align category_theory.localization.construction.lift_to_path_category CategoryTheory.Localization.Construction.liftToPathCategory
@[simps!]
def lift : W.Localization ⥤ D :=
Quotient.lift (relations W) (liftToPathCategory G hG)
(by
rintro ⟨X⟩ ⟨Y⟩ f₁ f₂ r
-- Porting note: rest of proof was `rcases r with ⟨⟩; tidy`
rcases r with (_|_|⟨f,hf⟩|⟨f,hf⟩)
· aesop_cat
· aesop_cat
all_goals
dsimp
haveI := hG f hf
simp
rfl)
#align category_theory.localization.construction.lift CategoryTheory.Localization.Construction.lift
@[simp]
theorem fac : W.Q ⋙ lift G hG = G :=
Functor.ext (fun X => rfl)
(by
intro X Y f
simp only [Functor.comp_map, eqToHom_refl, comp_id, id_comp]
dsimp [MorphismProperty.Q, Quot.liftOn, Quotient.functor]
rw [composePath_toPath])
#align category_theory.localization.construction.fac CategoryTheory.Localization.Construction.fac
theorem uniq (G₁ G₂ : W.Localization ⥤ D) (h : W.Q ⋙ G₁ = W.Q ⋙ G₂) : G₁ = G₂ := by
suffices h' : Quotient.functor _ ⋙ G₁ = Quotient.functor _ ⋙ G₂ by
refine Functor.ext ?_ ?_
· rintro ⟨⟨X⟩⟩
apply Functor.congr_obj h
· rintro ⟨⟨X⟩⟩ ⟨⟨Y⟩⟩ ⟨f⟩
apply Functor.congr_hom h'
refine Paths.ext_functor ?_ ?_
· ext X
cases X
apply Functor.congr_obj h
· rintro ⟨X⟩ ⟨Y⟩ (f | ⟨w, hw⟩)
· simpa only using Functor.congr_hom h f
· have hw : W.Q.map w = (wIso w hw).hom := rfl
have hw' := Functor.congr_hom h w
simp only [Functor.comp_map, hw] at hw'
refine Functor.congr_inv_of_congr_hom _ _ _ ?_ ?_ hw'
all_goals apply Functor.congr_obj h
#align category_theory.localization.construction.uniq CategoryTheory.Localization.Construction.uniq
variable (W)
@[simps]
def objEquiv : C ≃ W.Localization where
toFun := W.Q.obj
invFun X := X.as.obj
left_inv X := rfl
right_inv := by
rintro ⟨⟨X⟩⟩
rfl
#align category_theory.localization.construction.obj_equiv CategoryTheory.Localization.Construction.objEquiv
variable {W}
theorem morphismProperty_is_top (P : MorphismProperty W.Localization)
[P.IsStableUnderComposition] (hP₁ : ∀ ⦃X Y : C⦄ (f : X ⟶ Y), P (W.Q.map f))
(hP₂ : ∀ ⦃X Y : C⦄ (w : X ⟶ Y) (hw : W w), P (winv w hw)) :
P = ⊤ := by
funext X Y f
ext
constructor
· intro
apply MorphismProperty.top_apply
· intro
let G : _ ⥤ W.Localization := Quotient.functor _
haveI : G.Full := Quotient.full_functor _
suffices ∀ (X₁ X₂ : Paths (LocQuiver W)) (f : X₁ ⟶ X₂), P (G.map f) by
rcases X with ⟨⟨X⟩⟩
rcases Y with ⟨⟨Y⟩⟩
simpa only [Functor.map_preimage] using this _ _ (G.preimage f)
intros X₁ X₂ p
induction' p with X₂ X₃ p g hp
· simpa only [Functor.map_id] using hP₁ (𝟙 X₁.obj)
· let p' : X₁ ⟶X₂ := p
rw [show p'.cons g = p' ≫ Quiver.Hom.toPath g by rfl, G.map_comp]
refine P.comp_mem _ _ hp ?_
rcases g with (g | ⟨g, hg⟩)
· apply hP₁
· apply hP₂
#align category_theory.localization.construction.morphism_property_is_top CategoryTheory.Localization.Construction.morphismProperty_is_top
theorem morphismProperty_is_top' (P : MorphismProperty W.Localization)
[P.IsStableUnderComposition] (hP₁ : ∀ ⦃X Y : C⦄ (f : X ⟶ Y), P (W.Q.map f))
(hP₂ : ∀ ⦃X Y : W.Localization⦄ (e : X ≅ Y) (_ : P e.hom), P e.inv) : P = ⊤ :=
morphismProperty_is_top P hP₁ (fun _ _ w _ => hP₂ _ (hP₁ w))
#align category_theory.localization.construction.morphism_property_is_top' CategoryTheory.Localization.Construction.morphismProperty_is_top'
namespace NatTransExtension
variable {F₁ F₂ : W.Localization ⥤ D} (τ : W.Q ⋙ F₁ ⟶ W.Q ⋙ F₂)
def app (X : W.Localization) : F₁.obj X ⟶ F₂.obj X :=
eqToHom (congr_arg F₁.obj ((objEquiv W).right_inv X).symm) ≫
τ.app ((objEquiv W).invFun X) ≫ eqToHom (congr_arg F₂.obj ((objEquiv W).right_inv X))
#align category_theory.localization.construction.nat_trans_extension.app CategoryTheory.Localization.Construction.NatTransExtension.app
@[simp]
| Mathlib/CategoryTheory/Localization/Construction.lean | 281 | 283 | theorem app_eq (X : C) : (app τ) (W.Q.obj X) = τ.app X := by |
simp only [app, eqToHom_refl, comp_id, id_comp]
rfl
|
import Mathlib.Analysis.Calculus.Deriv.Inv
import Mathlib.Analysis.NormedSpace.BallAction
import Mathlib.Analysis.SpecialFunctions.ExpDeriv
import Mathlib.Analysis.InnerProductSpace.Calculus
import Mathlib.Analysis.InnerProductSpace.PiL2
import Mathlib.Geometry.Manifold.Algebra.LieGroup
import Mathlib.Geometry.Manifold.Instances.Real
import Mathlib.Geometry.Manifold.MFDeriv.Basic
#align_import geometry.manifold.instances.sphere from "leanprover-community/mathlib"@"0dc4079202c28226b2841a51eb6d3cc2135bb80f"
variable {E : Type*} [NormedAddCommGroup E] [InnerProductSpace ℝ E]
noncomputable section
open Metric FiniteDimensional Function
open scoped Manifold
section SmoothManifold
theorem sphere_ext_iff (u v : sphere (0 : E) 1) : u = v ↔ ⟪(u : E), v⟫_ℝ = 1 := by
simp [Subtype.ext_iff, inner_eq_one_iff_of_norm_one]
#align sphere_ext_iff sphere_ext_iff
| Mathlib/Geometry/Manifold/Instances/Sphere.lean | 389 | 396 | theorem stereographic'_symm_apply {n : ℕ} [Fact (finrank ℝ E = n + 1)] (v : sphere (0 : E) 1)
(x : EuclideanSpace ℝ (Fin n)) :
((stereographic' n v).symm x : E) =
let U : (ℝ ∙ (v : E))ᗮ ≃ₗᵢ[ℝ] EuclideanSpace ℝ (Fin n) :=
(OrthonormalBasis.fromOrthogonalSpanSingleton n (ne_zero_of_mem_unit_sphere v)).repr
(‖(U.symm x : E)‖ ^ 2 + 4)⁻¹ • (4 : ℝ) • (U.symm x : E) +
(‖(U.symm x : E)‖ ^ 2 + 4)⁻¹ • (‖(U.symm x : E)‖ ^ 2 - 4) • v.val := by |
simp [real_inner_comm, stereographic, stereographic', ← Submodule.coe_norm]
|
import Mathlib.Algebra.Order.Module.OrderedSMul
import Mathlib.Analysis.Convex.Star
import Mathlib.LinearAlgebra.AffineSpace.AffineSubspace
#align_import analysis.convex.basic from "leanprover-community/mathlib"@"92bd7b1ffeb306a89f450bee126ddd8a284c259d"
variable {𝕜 E F β : Type*}
open LinearMap Set
open scoped Convex Pointwise
section OrderedSemiring
variable [OrderedSemiring 𝕜]
section AddCommMonoid
variable [AddCommMonoid E] [AddCommMonoid F]
section Module
variable [Module 𝕜 E] [Module 𝕜 F] {s : Set E} {x : E}
theorem convex_iff_openSegment_subset :
Convex 𝕜 s ↔ ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → openSegment 𝕜 x y ⊆ s :=
forall₂_congr fun _ => starConvex_iff_openSegment_subset
#align convex_iff_open_segment_subset convex_iff_openSegment_subset
theorem convex_iff_forall_pos :
Convex 𝕜 s ↔
∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → a • x + b • y ∈ s :=
forall₂_congr fun _ => starConvex_iff_forall_pos
#align convex_iff_forall_pos convex_iff_forall_pos
theorem convex_iff_pairwise_pos : Convex 𝕜 s ↔
s.Pairwise fun x y => ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → a • x + b • y ∈ s := by
refine convex_iff_forall_pos.trans ⟨fun h x hx y hy _ => h hx hy, ?_⟩
intro h x hx y hy a b ha hb hab
obtain rfl | hxy := eq_or_ne x y
· rwa [Convex.combo_self hab]
· exact h hx hy hxy ha hb hab
#align convex_iff_pairwise_pos convex_iff_pairwise_pos
theorem Convex.starConvex_iff (hs : Convex 𝕜 s) (h : s.Nonempty) : StarConvex 𝕜 x s ↔ x ∈ s :=
⟨fun hxs => hxs.mem h, hs.starConvex⟩
#align convex.star_convex_iff Convex.starConvex_iff
protected theorem Set.Subsingleton.convex {s : Set E} (h : s.Subsingleton) : Convex 𝕜 s :=
convex_iff_pairwise_pos.mpr (h.pairwise _)
#align set.subsingleton.convex Set.Subsingleton.convex
theorem convex_singleton (c : E) : Convex 𝕜 ({c} : Set E) :=
subsingleton_singleton.convex
#align convex_singleton convex_singleton
theorem convex_zero : Convex 𝕜 (0 : Set E) :=
convex_singleton _
#align convex_zero convex_zero
theorem convex_segment (x y : E) : Convex 𝕜 [x -[𝕜] y] := by
rintro p ⟨ap, bp, hap, hbp, habp, rfl⟩ q ⟨aq, bq, haq, hbq, habq, rfl⟩ a b ha hb hab
refine
⟨a * ap + b * aq, a * bp + b * bq, add_nonneg (mul_nonneg ha hap) (mul_nonneg hb haq),
add_nonneg (mul_nonneg ha hbp) (mul_nonneg hb hbq), ?_, ?_⟩
· rw [add_add_add_comm, ← mul_add, ← mul_add, habp, habq, mul_one, mul_one, hab]
· simp_rw [add_smul, mul_smul, smul_add]
exact add_add_add_comm _ _ _ _
#align convex_segment convex_segment
theorem Convex.linear_image (hs : Convex 𝕜 s) (f : E →ₗ[𝕜] F) : Convex 𝕜 (f '' s) := by
rintro _ ⟨x, hx, rfl⟩ _ ⟨y, hy, rfl⟩ a b ha hb hab
exact ⟨a • x + b • y, hs hx hy ha hb hab, by rw [f.map_add, f.map_smul, f.map_smul]⟩
#align convex.linear_image Convex.linear_image
theorem Convex.is_linear_image (hs : Convex 𝕜 s) {f : E → F} (hf : IsLinearMap 𝕜 f) :
Convex 𝕜 (f '' s) :=
hs.linear_image <| hf.mk' f
#align convex.is_linear_image Convex.is_linear_image
theorem Convex.linear_preimage {s : Set F} (hs : Convex 𝕜 s) (f : E →ₗ[𝕜] F) :
Convex 𝕜 (f ⁻¹' s) := by
intro x hx y hy a b ha hb hab
rw [mem_preimage, f.map_add, f.map_smul, f.map_smul]
exact hs hx hy ha hb hab
#align convex.linear_preimage Convex.linear_preimage
theorem Convex.is_linear_preimage {s : Set F} (hs : Convex 𝕜 s) {f : E → F} (hf : IsLinearMap 𝕜 f) :
Convex 𝕜 (f ⁻¹' s) :=
hs.linear_preimage <| hf.mk' f
#align convex.is_linear_preimage Convex.is_linear_preimage
theorem Convex.add {t : Set E} (hs : Convex 𝕜 s) (ht : Convex 𝕜 t) : Convex 𝕜 (s + t) := by
rw [← add_image_prod]
exact (hs.prod ht).is_linear_image IsLinearMap.isLinearMap_add
#align convex.add Convex.add
variable (𝕜 E)
def convexAddSubmonoid : AddSubmonoid (Set E) where
carrier := {s : Set E | Convex 𝕜 s}
zero_mem' := convex_zero
add_mem' := Convex.add
#align convex_add_submonoid convexAddSubmonoid
@[simp, norm_cast]
theorem coe_convexAddSubmonoid : ↑(convexAddSubmonoid 𝕜 E) = {s : Set E | Convex 𝕜 s} :=
rfl
#align coe_convex_add_submonoid coe_convexAddSubmonoid
variable {𝕜 E}
@[simp]
theorem mem_convexAddSubmonoid {s : Set E} : s ∈ convexAddSubmonoid 𝕜 E ↔ Convex 𝕜 s :=
Iff.rfl
#align mem_convex_add_submonoid mem_convexAddSubmonoid
theorem convex_list_sum {l : List (Set E)} (h : ∀ i ∈ l, Convex 𝕜 i) : Convex 𝕜 l.sum :=
(convexAddSubmonoid 𝕜 E).list_sum_mem h
#align convex_list_sum convex_list_sum
theorem convex_multiset_sum {s : Multiset (Set E)} (h : ∀ i ∈ s, Convex 𝕜 i) : Convex 𝕜 s.sum :=
(convexAddSubmonoid 𝕜 E).multiset_sum_mem _ h
#align convex_multiset_sum convex_multiset_sum
theorem convex_sum {ι} {s : Finset ι} (t : ι → Set E) (h : ∀ i ∈ s, Convex 𝕜 (t i)) :
Convex 𝕜 (∑ i ∈ s, t i) :=
(convexAddSubmonoid 𝕜 E).sum_mem h
#align convex_sum convex_sum
theorem Convex.vadd (hs : Convex 𝕜 s) (z : E) : Convex 𝕜 (z +ᵥ s) := by
simp_rw [← image_vadd, vadd_eq_add, ← singleton_add]
exact (convex_singleton _).add hs
#align convex.vadd Convex.vadd
theorem Convex.translate (hs : Convex 𝕜 s) (z : E) : Convex 𝕜 ((fun x => z + x) '' s) :=
hs.vadd _
#align convex.translate Convex.translate
theorem Convex.translate_preimage_right (hs : Convex 𝕜 s) (z : E) :
Convex 𝕜 ((fun x => z + x) ⁻¹' s) := by
intro x hx y hy a b ha hb hab
have h := hs hx hy ha hb hab
rwa [smul_add, smul_add, add_add_add_comm, ← add_smul, hab, one_smul] at h
#align convex.translate_preimage_right Convex.translate_preimage_right
theorem Convex.translate_preimage_left (hs : Convex 𝕜 s) (z : E) :
Convex 𝕜 ((fun x => x + z) ⁻¹' s) := by
simpa only [add_comm] using hs.translate_preimage_right z
#align convex.translate_preimage_left Convex.translate_preimage_left
section OrderedRing
variable [OrderedRing 𝕜]
section
theorem Set.OrdConnected.convex_of_chain [OrderedSemiring 𝕜] [OrderedAddCommMonoid E] [Module 𝕜 E]
[OrderedSMul 𝕜 E] {s : Set E} (hs : s.OrdConnected) (h : IsChain (· ≤ ·) s) : Convex 𝕜 s := by
refine convex_iff_segment_subset.mpr fun x hx y hy => ?_
obtain hxy | hyx := h.total hx hy
· exact (segment_subset_Icc hxy).trans (hs.out hx hy)
· rw [segment_symm]
exact (segment_subset_Icc hyx).trans (hs.out hy hx)
#align set.ord_connected.convex_of_chain Set.OrdConnected.convex_of_chain
theorem Set.OrdConnected.convex [OrderedSemiring 𝕜] [LinearOrderedAddCommMonoid E] [Module 𝕜 E]
[OrderedSMul 𝕜 E] {s : Set E} (hs : s.OrdConnected) : Convex 𝕜 s :=
hs.convex_of_chain <| isChain_of_trichotomous s
#align set.ord_connected.convex Set.OrdConnected.convex
theorem convex_iff_ordConnected [LinearOrderedField 𝕜] {s : Set 𝕜} :
Convex 𝕜 s ↔ s.OrdConnected := by
simp_rw [convex_iff_segment_subset, segment_eq_uIcc, ordConnected_iff_uIcc_subset]
#align convex_iff_ord_connected convex_iff_ordConnected
alias ⟨Convex.ordConnected, _⟩ := convex_iff_ordConnected
#align convex.ord_connected Convex.ordConnected
end
section Simplex
section OrderedSemiring
variable (𝕜) (ι : Type*) [OrderedSemiring 𝕜] [Fintype ι]
def stdSimplex : Set (ι → 𝕜) :=
{ f | (∀ x, 0 ≤ f x) ∧ ∑ x, f x = 1 }
#align std_simplex stdSimplex
| Mathlib/Analysis/Convex/Basic.lean | 678 | 680 | theorem stdSimplex_eq_inter : stdSimplex 𝕜 ι = (⋂ x, { f | 0 ≤ f x }) ∩ { f | ∑ x, f x = 1 } := by |
ext f
simp only [stdSimplex, Set.mem_inter_iff, Set.mem_iInter, Set.mem_setOf_eq]
|
import Mathlib.Algebra.MonoidAlgebra.Degree
import Mathlib.Algebra.MvPolynomial.Rename
import Mathlib.Algebra.Order.BigOperators.Ring.Finset
#align_import data.mv_polynomial.variables from "leanprover-community/mathlib"@"2f5b500a507264de86d666a5f87ddb976e2d8de4"
noncomputable section
open Set Function Finsupp AddMonoidAlgebra
universe u v w
variable {R : Type u} {S : Type v}
namespace MvPolynomial
variable {σ τ : Type*} {r : R} {e : ℕ} {n m : σ} {s : σ →₀ ℕ}
section CommSemiring
variable [CommSemiring R] {p q : MvPolynomial σ R}
section Degrees
def degrees (p : MvPolynomial σ R) : Multiset σ :=
letI := Classical.decEq σ
p.support.sup fun s : σ →₀ ℕ => toMultiset s
#align mv_polynomial.degrees MvPolynomial.degrees
theorem degrees_def [DecidableEq σ] (p : MvPolynomial σ R) :
p.degrees = p.support.sup fun s : σ →₀ ℕ => Finsupp.toMultiset s := by rw [degrees]; convert rfl
#align mv_polynomial.degrees_def MvPolynomial.degrees_def
theorem degrees_monomial (s : σ →₀ ℕ) (a : R) : degrees (monomial s a) ≤ toMultiset s := by
classical
refine (supDegree_single s a).trans_le ?_
split_ifs
exacts [bot_le, le_rfl]
#align mv_polynomial.degrees_monomial MvPolynomial.degrees_monomial
theorem degrees_monomial_eq (s : σ →₀ ℕ) (a : R) (ha : a ≠ 0) :
degrees (monomial s a) = toMultiset s := by
classical
exact (supDegree_single s a).trans (if_neg ha)
#align mv_polynomial.degrees_monomial_eq MvPolynomial.degrees_monomial_eq
theorem degrees_C (a : R) : degrees (C a : MvPolynomial σ R) = 0 :=
Multiset.le_zero.1 <| degrees_monomial _ _
set_option linter.uppercaseLean3 false in
#align mv_polynomial.degrees_C MvPolynomial.degrees_C
theorem degrees_X' (n : σ) : degrees (X n : MvPolynomial σ R) ≤ {n} :=
le_trans (degrees_monomial _ _) <| le_of_eq <| toMultiset_single _ _
set_option linter.uppercaseLean3 false in
#align mv_polynomial.degrees_X' MvPolynomial.degrees_X'
@[simp]
theorem degrees_X [Nontrivial R] (n : σ) : degrees (X n : MvPolynomial σ R) = {n} :=
(degrees_monomial_eq _ (1 : R) one_ne_zero).trans (toMultiset_single _ _)
set_option linter.uppercaseLean3 false in
#align mv_polynomial.degrees_X MvPolynomial.degrees_X
@[simp]
theorem degrees_zero : degrees (0 : MvPolynomial σ R) = 0 := by
rw [← C_0]
exact degrees_C 0
#align mv_polynomial.degrees_zero MvPolynomial.degrees_zero
@[simp]
theorem degrees_one : degrees (1 : MvPolynomial σ R) = 0 :=
degrees_C 1
#align mv_polynomial.degrees_one MvPolynomial.degrees_one
theorem degrees_add [DecidableEq σ] (p q : MvPolynomial σ R) :
(p + q).degrees ≤ p.degrees ⊔ q.degrees := by
simp_rw [degrees_def]; exact supDegree_add_le
#align mv_polynomial.degrees_add MvPolynomial.degrees_add
theorem degrees_sum {ι : Type*} [DecidableEq σ] (s : Finset ι) (f : ι → MvPolynomial σ R) :
(∑ i ∈ s, f i).degrees ≤ s.sup fun i => (f i).degrees := by
simp_rw [degrees_def]; exact supDegree_sum_le
#align mv_polynomial.degrees_sum MvPolynomial.degrees_sum
theorem degrees_mul (p q : MvPolynomial σ R) : (p * q).degrees ≤ p.degrees + q.degrees := by
classical
simp_rw [degrees_def]
exact supDegree_mul_le (map_add _)
#align mv_polynomial.degrees_mul MvPolynomial.degrees_mul
theorem degrees_prod {ι : Type*} (s : Finset ι) (f : ι → MvPolynomial σ R) :
(∏ i ∈ s, f i).degrees ≤ ∑ i ∈ s, (f i).degrees := by
classical exact supDegree_prod_le (map_zero _) (map_add _)
#align mv_polynomial.degrees_prod MvPolynomial.degrees_prod
theorem degrees_pow (p : MvPolynomial σ R) (n : ℕ) : (p ^ n).degrees ≤ n • p.degrees := by
simpa using degrees_prod (Finset.range n) fun _ ↦ p
#align mv_polynomial.degrees_pow MvPolynomial.degrees_pow
theorem mem_degrees {p : MvPolynomial σ R} {i : σ} :
i ∈ p.degrees ↔ ∃ d, p.coeff d ≠ 0 ∧ i ∈ d.support := by
classical
simp only [degrees_def, Multiset.mem_sup, ← mem_support_iff, Finsupp.mem_toMultiset, exists_prop]
#align mv_polynomial.mem_degrees MvPolynomial.mem_degrees
theorem le_degrees_add {p q : MvPolynomial σ R} (h : p.degrees.Disjoint q.degrees) :
p.degrees ≤ (p + q).degrees := by
classical
apply Finset.sup_le
intro d hd
rw [Multiset.disjoint_iff_ne] at h
obtain rfl | h0 := eq_or_ne d 0
· rw [toMultiset_zero]; apply Multiset.zero_le
· refine Finset.le_sup_of_le (b := d) ?_ le_rfl
rw [mem_support_iff, coeff_add]
suffices q.coeff d = 0 by rwa [this, add_zero, coeff, ← Finsupp.mem_support_iff]
rw [Ne, ← Finsupp.support_eq_empty, ← Ne, ← Finset.nonempty_iff_ne_empty] at h0
obtain ⟨j, hj⟩ := h0
contrapose! h
rw [mem_support_iff] at hd
refine ⟨j, ?_, j, ?_, rfl⟩
all_goals rw [mem_degrees]; refine ⟨d, ?_, hj⟩; assumption
#align mv_polynomial.le_degrees_add MvPolynomial.le_degrees_add
theorem degrees_add_of_disjoint [DecidableEq σ] {p q : MvPolynomial σ R}
(h : Multiset.Disjoint p.degrees q.degrees) : (p + q).degrees = p.degrees ∪ q.degrees := by
apply le_antisymm
· apply degrees_add
· apply Multiset.union_le
· apply le_degrees_add h
· rw [add_comm]
apply le_degrees_add h.symm
#align mv_polynomial.degrees_add_of_disjoint MvPolynomial.degrees_add_of_disjoint
theorem degrees_map [CommSemiring S] (p : MvPolynomial σ R) (f : R →+* S) :
(map f p).degrees ⊆ p.degrees := by
classical
dsimp only [degrees]
apply Multiset.subset_of_le
apply Finset.sup_mono
apply MvPolynomial.support_map_subset
#align mv_polynomial.degrees_map MvPolynomial.degrees_map
| Mathlib/Algebra/MvPolynomial/Degrees.lean | 197 | 211 | theorem degrees_rename (f : σ → τ) (φ : MvPolynomial σ R) :
(rename f φ).degrees ⊆ φ.degrees.map f := by |
classical
intro i
rw [mem_degrees, Multiset.mem_map]
rintro ⟨d, hd, hi⟩
obtain ⟨x, rfl, hx⟩ := coeff_rename_ne_zero _ _ _ hd
simp only [Finsupp.mapDomain, Finsupp.mem_support_iff] at hi
rw [sum_apply, Finsupp.sum] at hi
contrapose! hi
rw [Finset.sum_eq_zero]
intro j hj
simp only [exists_prop, mem_degrees] at hi
specialize hi j ⟨x, hx, hj⟩
rw [Finsupp.single_apply, if_neg hi]
|
import Mathlib.Analysis.Calculus.Deriv.Add
#align_import analysis.calculus.local_extr from "leanprover-community/mathlib"@"3bce8d800a6f2b8f63fe1e588fd76a9ff4adcebe"
universe u v
open Filter Set
open scoped Topology Classical
section Module
variable {E : Type u} [NormedAddCommGroup E] [NormedSpace ℝ E] {f : E → ℝ} {a : E} {f' : E →L[ℝ] ℝ}
def posTangentConeAt (s : Set E) (x : E) : Set E :=
{ y : E | ∃ (c : ℕ → ℝ) (d : ℕ → E), (∀ᶠ n in atTop, x + d n ∈ s) ∧
Tendsto c atTop atTop ∧ Tendsto (fun n => c n • d n) atTop (𝓝 y) }
#align pos_tangent_cone_at posTangentConeAt
theorem posTangentConeAt_mono : Monotone fun s => posTangentConeAt s a := by
rintro s t hst y ⟨c, d, hd, hc, hcd⟩
exact ⟨c, d, mem_of_superset hd fun h hn => hst hn, hc, hcd⟩
#align pos_tangent_cone_at_mono posTangentConeAt_mono
theorem mem_posTangentConeAt_of_segment_subset {s : Set E} {x y : E} (h : segment ℝ x y ⊆ s) :
y - x ∈ posTangentConeAt s x := by
let c := fun n : ℕ => (2 : ℝ) ^ n
let d := fun n : ℕ => (c n)⁻¹ • (y - x)
refine ⟨c, d, Filter.univ_mem' fun n => h ?_, tendsto_pow_atTop_atTop_of_one_lt one_lt_two, ?_⟩
· show x + d n ∈ segment ℝ x y
rw [segment_eq_image']
refine ⟨(c n)⁻¹, ⟨?_, ?_⟩, rfl⟩
exacts [inv_nonneg.2 (pow_nonneg zero_le_two _), inv_le_one (one_le_pow_of_one_le one_le_two _)]
· show Tendsto (fun n => c n • d n) atTop (𝓝 (y - x))
exact tendsto_const_nhds.congr fun n ↦ (smul_inv_smul₀ (pow_ne_zero _ two_ne_zero) _).symm
#align mem_pos_tangent_cone_at_of_segment_subset mem_posTangentConeAt_of_segment_subset
theorem mem_posTangentConeAt_of_segment_subset' {s : Set E} {x y : E}
(h : segment ℝ x (x + y) ⊆ s) : y ∈ posTangentConeAt s x := by
simpa only [add_sub_cancel_left] using mem_posTangentConeAt_of_segment_subset h
#align mem_pos_tangent_cone_at_of_segment_subset' mem_posTangentConeAt_of_segment_subset'
theorem posTangentConeAt_univ : posTangentConeAt univ a = univ :=
eq_univ_of_forall fun _ => mem_posTangentConeAt_of_segment_subset' (subset_univ _)
#align pos_tangent_cone_at_univ posTangentConeAt_univ
theorem IsLocalMaxOn.hasFDerivWithinAt_nonpos {s : Set E} (h : IsLocalMaxOn f s a)
(hf : HasFDerivWithinAt f f' s a) {y} (hy : y ∈ posTangentConeAt s a) : f' y ≤ 0 := by
rcases hy with ⟨c, d, hd, hc, hcd⟩
have hc' : Tendsto (‖c ·‖) atTop atTop := tendsto_abs_atTop_atTop.comp hc
suffices ∀ᶠ n in atTop, c n • (f (a + d n) - f a) ≤ 0 from
le_of_tendsto (hf.lim atTop hd hc' hcd) this
replace hd : Tendsto (fun n => a + d n) atTop (𝓝[s] (a + 0)) :=
tendsto_nhdsWithin_iff.2 ⟨tendsto_const_nhds.add (tangentConeAt.lim_zero _ hc' hcd), hd⟩
rw [add_zero] at hd
filter_upwards [hd.eventually h, hc.eventually_ge_atTop 0] with n hfn hcn
exact mul_nonpos_of_nonneg_of_nonpos hcn (sub_nonpos.2 hfn)
#align is_local_max_on.has_fderiv_within_at_nonpos IsLocalMaxOn.hasFDerivWithinAt_nonpos
theorem IsLocalMaxOn.fderivWithin_nonpos {s : Set E} (h : IsLocalMaxOn f s a) {y}
(hy : y ∈ posTangentConeAt s a) : (fderivWithin ℝ f s a : E → ℝ) y ≤ 0 :=
if hf : DifferentiableWithinAt ℝ f s a then h.hasFDerivWithinAt_nonpos hf.hasFDerivWithinAt hy
else by rw [fderivWithin_zero_of_not_differentiableWithinAt hf]; rfl
#align is_local_max_on.fderiv_within_nonpos IsLocalMaxOn.fderivWithin_nonpos
theorem IsLocalMaxOn.hasFDerivWithinAt_eq_zero {s : Set E} (h : IsLocalMaxOn f s a)
(hf : HasFDerivWithinAt f f' s a) {y} (hy : y ∈ posTangentConeAt s a)
(hy' : -y ∈ posTangentConeAt s a) : f' y = 0 :=
le_antisymm (h.hasFDerivWithinAt_nonpos hf hy) <| by simpa using h.hasFDerivWithinAt_nonpos hf hy'
#align is_local_max_on.has_fderiv_within_at_eq_zero IsLocalMaxOn.hasFDerivWithinAt_eq_zero
theorem IsLocalMaxOn.fderivWithin_eq_zero {s : Set E} (h : IsLocalMaxOn f s a) {y}
(hy : y ∈ posTangentConeAt s a) (hy' : -y ∈ posTangentConeAt s a) :
(fderivWithin ℝ f s a : E → ℝ) y = 0 :=
if hf : DifferentiableWithinAt ℝ f s a then
h.hasFDerivWithinAt_eq_zero hf.hasFDerivWithinAt hy hy'
else by rw [fderivWithin_zero_of_not_differentiableWithinAt hf]; rfl
#align is_local_max_on.fderiv_within_eq_zero IsLocalMaxOn.fderivWithin_eq_zero
| Mathlib/Analysis/Calculus/LocalExtr/Basic.lean | 155 | 157 | theorem IsLocalMinOn.hasFDerivWithinAt_nonneg {s : Set E} (h : IsLocalMinOn f s a)
(hf : HasFDerivWithinAt f f' s a) {y} (hy : y ∈ posTangentConeAt s a) : 0 ≤ f' y := by |
simpa using h.neg.hasFDerivWithinAt_nonpos hf.neg hy
|
import Mathlib.Algebra.Algebra.Subalgebra.Directed
import Mathlib.FieldTheory.IntermediateField
import Mathlib.FieldTheory.Separable
import Mathlib.FieldTheory.SplittingField.IsSplittingField
import Mathlib.RingTheory.TensorProduct.Basic
#align_import field_theory.adjoin from "leanprover-community/mathlib"@"df76f43357840485b9d04ed5dee5ab115d420e87"
set_option autoImplicit true
open FiniteDimensional Polynomial
open scoped Classical Polynomial
namespace IntermediateField
section AdjoinDef
variable (F : Type*) [Field F] {E : Type*} [Field E] [Algebra F E] (S : Set E)
theorem adjoin_eq_range_algebraMap_adjoin :
(adjoin F S : Set E) = Set.range (algebraMap (adjoin F S) E) :=
Subtype.range_coe.symm
#align intermediate_field.adjoin_eq_range_algebra_map_adjoin IntermediateField.adjoin_eq_range_algebraMap_adjoin
theorem adjoin.algebraMap_mem (x : F) : algebraMap F E x ∈ adjoin F S :=
IntermediateField.algebraMap_mem (adjoin F S) x
#align intermediate_field.adjoin.algebra_map_mem IntermediateField.adjoin.algebraMap_mem
theorem adjoin.range_algebraMap_subset : Set.range (algebraMap F E) ⊆ adjoin F S := by
intro x hx
cases' hx with f hf
rw [← hf]
exact adjoin.algebraMap_mem F S f
#align intermediate_field.adjoin.range_algebra_map_subset IntermediateField.adjoin.range_algebraMap_subset
instance adjoin.fieldCoe : CoeTC F (adjoin F S) where
coe x := ⟨algebraMap F E x, adjoin.algebraMap_mem F S x⟩
#align intermediate_field.adjoin.field_coe IntermediateField.adjoin.fieldCoe
theorem subset_adjoin : S ⊆ adjoin F S := fun _ hx => Subfield.subset_closure (Or.inr hx)
#align intermediate_field.subset_adjoin IntermediateField.subset_adjoin
instance adjoin.setCoe : CoeTC S (adjoin F S) where coe x := ⟨x, subset_adjoin F S (Subtype.mem x)⟩
#align intermediate_field.adjoin.set_coe IntermediateField.adjoin.setCoe
@[mono]
theorem adjoin.mono (T : Set E) (h : S ⊆ T) : adjoin F S ≤ adjoin F T :=
GaloisConnection.monotone_l gc h
#align intermediate_field.adjoin.mono IntermediateField.adjoin.mono
theorem adjoin_contains_field_as_subfield (F : Subfield E) : (F : Set E) ⊆ adjoin F S := fun x hx =>
adjoin.algebraMap_mem F S ⟨x, hx⟩
#align intermediate_field.adjoin_contains_field_as_subfield IntermediateField.adjoin_contains_field_as_subfield
theorem subset_adjoin_of_subset_left {F : Subfield E} {T : Set E} (HT : T ⊆ F) : T ⊆ adjoin F S :=
fun x hx => (adjoin F S).algebraMap_mem ⟨x, HT hx⟩
#align intermediate_field.subset_adjoin_of_subset_left IntermediateField.subset_adjoin_of_subset_left
theorem subset_adjoin_of_subset_right {T : Set E} (H : T ⊆ S) : T ⊆ adjoin F S := fun _ hx =>
subset_adjoin F S (H hx)
#align intermediate_field.subset_adjoin_of_subset_right IntermediateField.subset_adjoin_of_subset_right
@[simp]
theorem adjoin_empty (F E : Type*) [Field F] [Field E] [Algebra F E] : adjoin F (∅ : Set E) = ⊥ :=
eq_bot_iff.mpr (adjoin_le_iff.mpr (Set.empty_subset _))
#align intermediate_field.adjoin_empty IntermediateField.adjoin_empty
@[simp]
theorem adjoin_univ (F E : Type*) [Field F] [Field E] [Algebra F E] :
adjoin F (Set.univ : Set E) = ⊤ :=
eq_top_iff.mpr <| subset_adjoin _ _
#align intermediate_field.adjoin_univ IntermediateField.adjoin_univ
theorem adjoin_le_subfield {K : Subfield E} (HF : Set.range (algebraMap F E) ⊆ K) (HS : S ⊆ K) :
(adjoin F S).toSubfield ≤ K := by
apply Subfield.closure_le.mpr
rw [Set.union_subset_iff]
exact ⟨HF, HS⟩
#align intermediate_field.adjoin_le_subfield IntermediateField.adjoin_le_subfield
theorem adjoin_subset_adjoin_iff {F' : Type*} [Field F'] [Algebra F' E] {S S' : Set E} :
(adjoin F S : Set E) ⊆ adjoin F' S' ↔
Set.range (algebraMap F E) ⊆ adjoin F' S' ∧ S ⊆ adjoin F' S' :=
⟨fun h => ⟨(adjoin.range_algebraMap_subset _ _).trans h,
(subset_adjoin _ _).trans h⟩, fun ⟨hF, hS⟩ =>
(Subfield.closure_le (t := (adjoin F' S').toSubfield)).mpr (Set.union_subset hF hS)⟩
#align intermediate_field.adjoin_subset_adjoin_iff IntermediateField.adjoin_subset_adjoin_iff
theorem adjoin_adjoin_left (T : Set E) :
(adjoin (adjoin F S) T).restrictScalars _ = adjoin F (S ∪ T) := by
rw [SetLike.ext'_iff]
change (↑(adjoin (adjoin F S) T) : Set E) = _
apply Set.eq_of_subset_of_subset <;> rw [adjoin_subset_adjoin_iff] <;> constructor
· rintro _ ⟨⟨x, hx⟩, rfl⟩; exact adjoin.mono _ _ _ Set.subset_union_left hx
· exact subset_adjoin_of_subset_right _ _ Set.subset_union_right
-- Porting note: orginal proof times out
· rintro x ⟨f, rfl⟩
refine Subfield.subset_closure ?_
left
exact ⟨f, rfl⟩
-- Porting note: orginal proof times out
· refine Set.union_subset (fun x hx => Subfield.subset_closure ?_)
(fun x hx => Subfield.subset_closure ?_)
· left
refine ⟨⟨x, Subfield.subset_closure ?_⟩, rfl⟩
right
exact hx
· right
exact hx
#align intermediate_field.adjoin_adjoin_left IntermediateField.adjoin_adjoin_left
@[simp]
theorem adjoin_insert_adjoin (x : E) :
adjoin F (insert x (adjoin F S : Set E)) = adjoin F (insert x S) :=
le_antisymm
(adjoin_le_iff.mpr
(Set.insert_subset_iff.mpr
⟨subset_adjoin _ _ (Set.mem_insert _ _),
adjoin_le_iff.mpr (subset_adjoin_of_subset_right _ _ (Set.subset_insert _ _))⟩))
(adjoin.mono _ _ _ (Set.insert_subset_insert (subset_adjoin _ _)))
#align intermediate_field.adjoin_insert_adjoin IntermediateField.adjoin_insert_adjoin
theorem adjoin_adjoin_comm (T : Set E) :
(adjoin (adjoin F S) T).restrictScalars F = (adjoin (adjoin F T) S).restrictScalars F := by
rw [adjoin_adjoin_left, adjoin_adjoin_left, Set.union_comm]
#align intermediate_field.adjoin_adjoin_comm IntermediateField.adjoin_adjoin_comm
theorem adjoin_map {E' : Type*} [Field E'] [Algebra F E'] (f : E →ₐ[F] E') :
(adjoin F S).map f = adjoin F (f '' S) := by
ext x
show
x ∈ (Subfield.closure (Set.range (algebraMap F E) ∪ S)).map (f : E →+* E') ↔
x ∈ Subfield.closure (Set.range (algebraMap F E') ∪ f '' S)
rw [RingHom.map_field_closure, Set.image_union, ← Set.range_comp, ← RingHom.coe_comp,
f.comp_algebraMap]
rfl
#align intermediate_field.adjoin_map IntermediateField.adjoin_map
@[simp]
theorem lift_adjoin (K : IntermediateField F E) (S : Set K) :
lift (adjoin F S) = adjoin F (Subtype.val '' S) :=
adjoin_map _ _ _
theorem lift_adjoin_simple (K : IntermediateField F E) (α : K) :
lift (adjoin F {α}) = adjoin F {α.1} := by
simp only [lift_adjoin, Set.image_singleton]
@[simp]
theorem lift_bot (K : IntermediateField F E) :
lift (F := K) ⊥ = ⊥ := map_bot _
@[simp]
theorem lift_top (K : IntermediateField F E) :
lift (F := K) ⊤ = K := by rw [lift, ← AlgHom.fieldRange_eq_map, fieldRange_val]
@[simp]
theorem adjoin_self (K : IntermediateField F E) :
adjoin F K = K := le_antisymm (adjoin_le_iff.2 fun _ ↦ id) (subset_adjoin F _)
theorem restrictScalars_adjoin (K : IntermediateField F E) (S : Set E) :
restrictScalars F (adjoin K S) = adjoin F (K ∪ S) := by
rw [← adjoin_self _ K, adjoin_adjoin_left, adjoin_self _ K]
variable {F} in
theorem extendScalars_adjoin {K : IntermediateField F E} {S : Set E} (h : K ≤ adjoin F S) :
extendScalars h = adjoin K S := restrictScalars_injective F <| by
rw [extendScalars_restrictScalars, restrictScalars_adjoin]
exact le_antisymm (adjoin.mono F S _ Set.subset_union_right) <| adjoin_le_iff.2 <|
Set.union_subset h (subset_adjoin F S)
variable {F} in
theorem restrictScalars_adjoin_of_algEquiv
{L L' : Type*} [Field L] [Field L']
[Algebra F L] [Algebra L E] [Algebra F L'] [Algebra L' E]
[IsScalarTower F L E] [IsScalarTower F L' E] (i : L ≃ₐ[F] L')
(hi : algebraMap L E = (algebraMap L' E) ∘ i) (S : Set E) :
(adjoin L S).restrictScalars F = (adjoin L' S).restrictScalars F := by
apply_fun toSubfield using (fun K K' h ↦ by
ext x; change x ∈ K.toSubfield ↔ x ∈ K'.toSubfield; rw [h])
change Subfield.closure _ = Subfield.closure _
congr
ext x
exact ⟨fun ⟨y, h⟩ ↦ ⟨i y, by rw [← h, hi]; rfl⟩,
fun ⟨y, h⟩ ↦ ⟨i.symm y, by rw [← h, hi, Function.comp_apply, AlgEquiv.apply_symm_apply]⟩⟩
theorem algebra_adjoin_le_adjoin : Algebra.adjoin F S ≤ (adjoin F S).toSubalgebra :=
Algebra.adjoin_le (subset_adjoin _ _)
#align intermediate_field.algebra_adjoin_le_adjoin IntermediateField.algebra_adjoin_le_adjoin
theorem adjoin_eq_algebra_adjoin (inv_mem : ∀ x ∈ Algebra.adjoin F S, x⁻¹ ∈ Algebra.adjoin F S) :
(adjoin F S).toSubalgebra = Algebra.adjoin F S :=
le_antisymm
(show adjoin F S ≤
{ Algebra.adjoin F S with
inv_mem' := inv_mem }
from adjoin_le_iff.mpr Algebra.subset_adjoin)
(algebra_adjoin_le_adjoin _ _)
#align intermediate_field.adjoin_eq_algebra_adjoin IntermediateField.adjoin_eq_algebra_adjoin
theorem eq_adjoin_of_eq_algebra_adjoin (K : IntermediateField F E)
(h : K.toSubalgebra = Algebra.adjoin F S) : K = adjoin F S := by
apply toSubalgebra_injective
rw [h]
refine (adjoin_eq_algebra_adjoin F _ ?_).symm
intro x
convert K.inv_mem (x := x) <;> rw [← h] <;> rfl
#align intermediate_field.eq_adjoin_of_eq_algebra_adjoin IntermediateField.eq_adjoin_of_eq_algebra_adjoin
theorem adjoin_eq_top_of_algebra (hS : Algebra.adjoin F S = ⊤) : adjoin F S = ⊤ :=
top_le_iff.mp (hS.symm.trans_le <| algebra_adjoin_le_adjoin F S)
@[elab_as_elim]
theorem adjoin_induction {s : Set E} {p : E → Prop} {x} (h : x ∈ adjoin F s) (mem : ∀ x ∈ s, p x)
(algebraMap : ∀ x, p (algebraMap F E x)) (add : ∀ x y, p x → p y → p (x + y))
(neg : ∀ x, p x → p (-x)) (inv : ∀ x, p x → p x⁻¹) (mul : ∀ x y, p x → p y → p (x * y)) :
p x :=
Subfield.closure_induction h
(fun x hx => Or.casesOn hx (fun ⟨x, hx⟩ => hx ▸ algebraMap x) (mem x))
((_root_.algebraMap F E).map_one ▸ algebraMap 1) add neg inv mul
#align intermediate_field.adjoin_induction IntermediateField.adjoin_induction
open Lean in
private partial def mkInsertTerm [Monad m] [MonadQuotation m] (xs : TSyntaxArray `term) : m Term :=
run 0
where
run (i : Nat) : m Term := do
if i + 1 == xs.size then
``(singleton $(xs[i]!))
else if i < xs.size then
``(insert $(xs[i]!) $(← run (i + 1)))
else
``(EmptyCollection.emptyCollection)
scoped macro:max K:term "⟮" xs:term,* "⟯" : term => do ``(adjoin $K $(← mkInsertTerm xs.getElems))
open Lean PrettyPrinter.Delaborator SubExpr in
@[delab app.IntermediateField.adjoin]
partial def delabAdjoinNotation : Delab := whenPPOption getPPNotation do
let e ← getExpr
guard <| e.isAppOfArity ``adjoin 6
let F ← withNaryArg 0 delab
let xs ← withNaryArg 5 delabInsertArray
`($F⟮$(xs.toArray),*⟯)
where
delabInsertArray : DelabM (List Term) := do
let e ← getExpr
if e.isAppOfArity ``EmptyCollection.emptyCollection 2 then
return []
else if e.isAppOfArity ``singleton 4 then
let x ← withNaryArg 3 delab
return [x]
else if e.isAppOfArity ``insert 5 then
let x ← withNaryArg 3 delab
let xs ← withNaryArg 4 delabInsertArray
return x :: xs
else failure
section AdjoinSimple
variable (α : E)
-- Porting note: in all the theorems below, mathport translated `F⟮α⟯` into `F⟮⟯`.
theorem mem_adjoin_simple_self : α ∈ F⟮α⟯ :=
subset_adjoin F {α} (Set.mem_singleton α)
#align intermediate_field.mem_adjoin_simple_self IntermediateField.mem_adjoin_simple_self
def AdjoinSimple.gen : F⟮α⟯ :=
⟨α, mem_adjoin_simple_self F α⟩
#align intermediate_field.adjoin_simple.gen IntermediateField.AdjoinSimple.gen
@[simp]
theorem AdjoinSimple.coe_gen : (AdjoinSimple.gen F α : E) = α :=
rfl
theorem AdjoinSimple.algebraMap_gen : algebraMap F⟮α⟯ E (AdjoinSimple.gen F α) = α :=
rfl
#align intermediate_field.adjoin_simple.algebra_map_gen IntermediateField.AdjoinSimple.algebraMap_gen
@[simp]
theorem AdjoinSimple.isIntegral_gen : IsIntegral F (AdjoinSimple.gen F α) ↔ IsIntegral F α := by
conv_rhs => rw [← AdjoinSimple.algebraMap_gen F α]
rw [isIntegral_algebraMap_iff (algebraMap F⟮α⟯ E).injective]
#align intermediate_field.adjoin_simple.is_integral_gen IntermediateField.AdjoinSimple.isIntegral_gen
theorem adjoin_simple_adjoin_simple (β : E) : F⟮α⟯⟮β⟯.restrictScalars F = F⟮α, β⟯ :=
adjoin_adjoin_left _ _ _
#align intermediate_field.adjoin_simple_adjoin_simple IntermediateField.adjoin_simple_adjoin_simple
theorem adjoin_simple_comm (β : E) : F⟮α⟯⟮β⟯.restrictScalars F = F⟮β⟯⟮α⟯.restrictScalars F :=
adjoin_adjoin_comm _ _ _
#align intermediate_field.adjoin_simple_comm IntermediateField.adjoin_simple_comm
variable {F} {α}
theorem adjoin_algebraic_toSubalgebra {S : Set E} (hS : ∀ x ∈ S, IsAlgebraic F x) :
(IntermediateField.adjoin F S).toSubalgebra = Algebra.adjoin F S := by
simp only [isAlgebraic_iff_isIntegral] at hS
have : Algebra.IsIntegral F (Algebra.adjoin F S) := by
rwa [← le_integralClosure_iff_isIntegral, Algebra.adjoin_le_iff]
have : IsField (Algebra.adjoin F S) := isField_of_isIntegral_of_isField' (Field.toIsField F)
rw [← ((Algebra.adjoin F S).toIntermediateField' this).eq_adjoin_of_eq_algebra_adjoin F S] <;> rfl
#align intermediate_field.adjoin_algebraic_to_subalgebra IntermediateField.adjoin_algebraic_toSubalgebra
theorem adjoin_simple_toSubalgebra_of_integral (hα : IsIntegral F α) :
F⟮α⟯.toSubalgebra = Algebra.adjoin F {α} := by
apply adjoin_algebraic_toSubalgebra
rintro x (rfl : x = α)
rwa [isAlgebraic_iff_isIntegral]
#align intermediate_field.adjoin_simple_to_subalgebra_of_integral IntermediateField.adjoin_simple_toSubalgebra_of_integral
theorem _root_.isSplittingField_iff_intermediateField {p : F[X]} :
p.IsSplittingField F E ↔ p.Splits (algebraMap F E) ∧ adjoin F (p.rootSet E) = ⊤ := by
rw [← toSubalgebra_injective.eq_iff,
adjoin_algebraic_toSubalgebra fun _ ↦ isAlgebraic_of_mem_rootSet]
exact ⟨fun ⟨spl, adj⟩ ↦ ⟨spl, adj⟩, fun ⟨spl, adj⟩ ↦ ⟨spl, adj⟩⟩
-- Note: p.Splits (algebraMap F E) also works
theorem isSplittingField_iff {p : F[X]} {K : IntermediateField F E} :
p.IsSplittingField F K ↔ p.Splits (algebraMap F K) ∧ K = adjoin F (p.rootSet E) := by
suffices _ → (Algebra.adjoin F (p.rootSet K) = ⊤ ↔ K = adjoin F (p.rootSet E)) by
exact ⟨fun h ↦ ⟨h.1, (this h.1).mp h.2⟩, fun h ↦ ⟨h.1, (this h.1).mpr h.2⟩⟩
rw [← toSubalgebra_injective.eq_iff,
adjoin_algebraic_toSubalgebra fun x ↦ isAlgebraic_of_mem_rootSet]
refine fun hp ↦ (adjoin_rootSet_eq_range hp K.val).symm.trans ?_
rw [← K.range_val, eq_comm]
#align intermediate_field.is_splitting_field_iff IntermediateField.isSplittingField_iff
theorem adjoin_rootSet_isSplittingField {p : F[X]} (hp : p.Splits (algebraMap F E)) :
p.IsSplittingField F (adjoin F (p.rootSet E)) :=
isSplittingField_iff.mpr ⟨splits_of_splits hp fun _ hx ↦ subset_adjoin F (p.rootSet E) hx, rfl⟩
#align intermediate_field.adjoin_root_set_is_splitting_field IntermediateField.adjoin_rootSet_isSplittingField
section AdjoinIntermediateFieldLattice
variable {F : Type*} [Field F] {E : Type*} [Field E] [Algebra F E] {α : E} {S : Set E}
@[simp]
| Mathlib/FieldTheory/Adjoin.lean | 929 | 930 | theorem adjoin_eq_bot_iff : adjoin F S = ⊥ ↔ S ⊆ (⊥ : IntermediateField F E) := by |
rw [eq_bot_iff, adjoin_le_iff]; rfl
|
import Mathlib.Algebra.Order.Ring.Int
import Mathlib.Algebra.Ring.Rat
#align_import data.rat.order from "leanprover-community/mathlib"@"a59dad53320b73ef180174aae867addd707ef00e"
assert_not_exists Field
assert_not_exists Finset
assert_not_exists Set.Icc
assert_not_exists GaloisConnection
namespace Rat
variable {a b c p q : ℚ}
@[simp] lemma divInt_nonneg_iff_of_pos_right {a b : ℤ} (hb : 0 < b) : 0 ≤ a /. b ↔ 0 ≤ a := by
cases' hab : a /. b with n d hd hnd
rw [mk'_eq_divInt, divInt_eq_iff hb.ne' (mod_cast hd)] at hab
rw [← num_nonneg, ← mul_nonneg_iff_of_pos_right hb, ← hab,
mul_nonneg_iff_of_pos_right (mod_cast Nat.pos_of_ne_zero hd)]
#align rat.mk_nonneg Rat.divInt_nonneg_iff_of_pos_right
@[simp] lemma divInt_nonneg {a b : ℤ} (ha : 0 ≤ a) (hb : 0 ≤ b) : 0 ≤ a /. b := by
obtain rfl | hb := hb.eq_or_lt
· simp
rfl
rwa [divInt_nonneg_iff_of_pos_right hb]
@[simp] lemma mkRat_nonneg {a : ℤ} (ha : 0 ≤ a) (b : ℕ) : 0 ≤ mkRat a b := by
simpa using divInt_nonneg ha (Int.natCast_nonneg _)
| Mathlib/Algebra/Order/Ring/Rat.lean | 50 | 59 | theorem ofScientific_nonneg (m : ℕ) (s : Bool) (e : ℕ) :
0 ≤ Rat.ofScientific m s e := by |
rw [Rat.ofScientific]
cases s
· rw [if_neg (by decide)]
refine num_nonneg.mp ?_
rw [num_natCast]
exact Int.natCast_nonneg _
· rw [if_pos rfl, normalize_eq_mkRat]
exact Rat.mkRat_nonneg (Int.natCast_nonneg _) _
|
import Mathlib.Algebra.GroupWithZero.Divisibility
import Mathlib.Algebra.MonoidAlgebra.Basic
import Mathlib.Data.Finset.Sort
#align_import data.polynomial.basic from "leanprover-community/mathlib"@"949dc57e616a621462062668c9f39e4e17b64b69"
set_option linter.uppercaseLean3 false
noncomputable section
structure Polynomial (R : Type*) [Semiring R] where ofFinsupp ::
toFinsupp : AddMonoidAlgebra R ℕ
#align polynomial Polynomial
#align polynomial.of_finsupp Polynomial.ofFinsupp
#align polynomial.to_finsupp Polynomial.toFinsupp
@[inherit_doc] scoped[Polynomial] notation:9000 R "[X]" => Polynomial R
open AddMonoidAlgebra
open Finsupp hiding single
open Function hiding Commute
open Polynomial
namespace Polynomial
universe u
variable {R : Type u} {a b : R} {m n : ℕ}
section Semiring
variable [Semiring R] {p q : R[X]}
theorem forall_iff_forall_finsupp (P : R[X] → Prop) :
(∀ p, P p) ↔ ∀ q : R[ℕ], P ⟨q⟩ :=
⟨fun h q => h ⟨q⟩, fun h ⟨p⟩ => h p⟩
#align polynomial.forall_iff_forall_finsupp Polynomial.forall_iff_forall_finsupp
theorem exists_iff_exists_finsupp (P : R[X] → Prop) :
(∃ p, P p) ↔ ∃ q : R[ℕ], P ⟨q⟩ :=
⟨fun ⟨⟨p⟩, hp⟩ => ⟨p, hp⟩, fun ⟨q, hq⟩ => ⟨⟨q⟩, hq⟩⟩
#align polynomial.exists_iff_exists_finsupp Polynomial.exists_iff_exists_finsupp
@[simp]
theorem eta (f : R[X]) : Polynomial.ofFinsupp f.toFinsupp = f := by cases f; rfl
#align polynomial.eta Polynomial.eta
section AddMonoidAlgebra
private irreducible_def add : R[X] → R[X] → R[X]
| ⟨a⟩, ⟨b⟩ => ⟨a + b⟩
private irreducible_def neg {R : Type u} [Ring R] : R[X] → R[X]
| ⟨a⟩ => ⟨-a⟩
private irreducible_def mul : R[X] → R[X] → R[X]
| ⟨a⟩, ⟨b⟩ => ⟨a * b⟩
instance zero : Zero R[X] :=
⟨⟨0⟩⟩
#align polynomial.has_zero Polynomial.zero
instance one : One R[X] :=
⟨⟨1⟩⟩
#align polynomial.one Polynomial.one
instance add' : Add R[X] :=
⟨add⟩
#align polynomial.has_add Polynomial.add'
instance neg' {R : Type u} [Ring R] : Neg R[X] :=
⟨neg⟩
#align polynomial.has_neg Polynomial.neg'
instance sub {R : Type u} [Ring R] : Sub R[X] :=
⟨fun a b => a + -b⟩
#align polynomial.has_sub Polynomial.sub
instance mul' : Mul R[X] :=
⟨mul⟩
#align polynomial.has_mul Polynomial.mul'
-- If the private definitions are accidentally exposed, simplify them away.
@[simp] theorem add_eq_add : add p q = p + q := rfl
@[simp] theorem mul_eq_mul : mul p q = p * q := rfl
instance smulZeroClass {S : Type*} [SMulZeroClass S R] : SMulZeroClass S R[X] where
smul r p := ⟨r • p.toFinsupp⟩
smul_zero a := congr_arg ofFinsupp (smul_zero a)
#align polynomial.smul_zero_class Polynomial.smulZeroClass
-- to avoid a bug in the `ring` tactic
instance (priority := 1) pow : Pow R[X] ℕ where pow p n := npowRec n p
#align polynomial.has_pow Polynomial.pow
@[simp]
theorem ofFinsupp_zero : (⟨0⟩ : R[X]) = 0 :=
rfl
#align polynomial.of_finsupp_zero Polynomial.ofFinsupp_zero
@[simp]
theorem ofFinsupp_one : (⟨1⟩ : R[X]) = 1 :=
rfl
#align polynomial.of_finsupp_one Polynomial.ofFinsupp_one
@[simp]
theorem ofFinsupp_add {a b} : (⟨a + b⟩ : R[X]) = ⟨a⟩ + ⟨b⟩ :=
show _ = add _ _ by rw [add_def]
#align polynomial.of_finsupp_add Polynomial.ofFinsupp_add
@[simp]
theorem ofFinsupp_neg {R : Type u} [Ring R] {a} : (⟨-a⟩ : R[X]) = -⟨a⟩ :=
show _ = neg _ by rw [neg_def]
#align polynomial.of_finsupp_neg Polynomial.ofFinsupp_neg
@[simp]
theorem ofFinsupp_sub {R : Type u} [Ring R] {a b} : (⟨a - b⟩ : R[X]) = ⟨a⟩ - ⟨b⟩ := by
rw [sub_eq_add_neg, ofFinsupp_add, ofFinsupp_neg]
rfl
#align polynomial.of_finsupp_sub Polynomial.ofFinsupp_sub
@[simp]
theorem ofFinsupp_mul (a b) : (⟨a * b⟩ : R[X]) = ⟨a⟩ * ⟨b⟩ :=
show _ = mul _ _ by rw [mul_def]
#align polynomial.of_finsupp_mul Polynomial.ofFinsupp_mul
@[simp]
theorem ofFinsupp_smul {S : Type*} [SMulZeroClass S R] (a : S) (b) :
(⟨a • b⟩ : R[X]) = (a • ⟨b⟩ : R[X]) :=
rfl
#align polynomial.of_finsupp_smul Polynomial.ofFinsupp_smul
@[simp]
| Mathlib/Algebra/Polynomial/Basic.lean | 195 | 199 | theorem ofFinsupp_pow (a) (n : ℕ) : (⟨a ^ n⟩ : R[X]) = ⟨a⟩ ^ n := by |
change _ = npowRec n _
induction n with
| zero => simp [npowRec]
| succ n n_ih => simp [npowRec, n_ih, pow_succ]
|
import Mathlib.Data.Multiset.Nodup
import Mathlib.Data.List.NatAntidiagonal
#align_import data.multiset.nat_antidiagonal from "leanprover-community/mathlib"@"9003f28797c0664a49e4179487267c494477d853"
namespace Multiset
namespace Nat
def antidiagonal (n : ℕ) : Multiset (ℕ × ℕ) :=
List.Nat.antidiagonal n
#align multiset.nat.antidiagonal Multiset.Nat.antidiagonal
@[simp]
| Mathlib/Data/Multiset/NatAntidiagonal.lean | 36 | 37 | theorem mem_antidiagonal {n : ℕ} {x : ℕ × ℕ} : x ∈ antidiagonal n ↔ x.1 + x.2 = n := by |
rw [antidiagonal, mem_coe, List.Nat.mem_antidiagonal]
|
import Mathlib.Data.PNat.Defs
import Mathlib.Algebra.Order.Ring.Nat
import Mathlib.Data.Set.Basic
import Mathlib.Algebra.GroupWithZero.Divisibility
import Mathlib.Algebra.Order.Positive.Ring
import Mathlib.Order.Hom.Basic
#align_import data.pnat.basic from "leanprover-community/mathlib"@"172bf2812857f5e56938cc148b7a539f52f84ca9"
deriving instance AddLeftCancelSemigroup, AddRightCancelSemigroup, AddCommSemigroup,
LinearOrderedCancelCommMonoid, Add, Mul, Distrib for PNat
namespace PNat
open Nat
@[simp, norm_cast]
theorem coe_inj {m n : ℕ+} : (m : ℕ) = n ↔ m = n :=
SetCoe.ext_iff
#align pnat.coe_inj PNat.coe_inj
@[simp, norm_cast]
theorem add_coe (m n : ℕ+) : ((m + n : ℕ+) : ℕ) = m + n :=
rfl
#align pnat.add_coe PNat.add_coe
def coeAddHom : AddHom ℕ+ ℕ where
toFun := Coe.coe
map_add' := add_coe
#align pnat.coe_add_hom PNat.coeAddHom
instance covariantClass_add_le : CovariantClass ℕ+ ℕ+ (· + ·) (· ≤ ·) :=
Positive.covariantClass_add_le
instance covariantClass_add_lt : CovariantClass ℕ+ ℕ+ (· + ·) (· < ·) :=
Positive.covariantClass_add_lt
instance contravariantClass_add_le : ContravariantClass ℕ+ ℕ+ (· + ·) (· ≤ ·) :=
Positive.contravariantClass_add_le
instance contravariantClass_add_lt : ContravariantClass ℕ+ ℕ+ (· + ·) (· < ·) :=
Positive.contravariantClass_add_lt
@[simps (config := .asFn)]
def _root_.Equiv.pnatEquivNat : ℕ+ ≃ ℕ where
toFun := PNat.natPred
invFun := Nat.succPNat
left_inv := succPNat_natPred
right_inv := Nat.natPred_succPNat
#align equiv.pnat_equiv_nat Equiv.pnatEquivNat
#align equiv.pnat_equiv_nat_symm_apply Equiv.pnatEquivNat_symm_apply
#align equiv.pnat_equiv_nat_apply Equiv.pnatEquivNat_apply
@[simps! (config := .asFn) apply]
def _root_.OrderIso.pnatIsoNat : ℕ+ ≃o ℕ where
toEquiv := Equiv.pnatEquivNat
map_rel_iff' := natPred_le_natPred
#align order_iso.pnat_iso_nat OrderIso.pnatIsoNat
#align order_iso.pnat_iso_nat_apply OrderIso.pnatIsoNat_apply
@[simp]
theorem _root_.OrderIso.pnatIsoNat_symm_apply : OrderIso.pnatIsoNat.symm = Nat.succPNat :=
rfl
#align order_iso.pnat_iso_nat_symm_apply OrderIso.pnatIsoNat_symm_apply
theorem lt_add_one_iff : ∀ {a b : ℕ+}, a < b + 1 ↔ a ≤ b := Nat.lt_add_one_iff
#align pnat.lt_add_one_iff PNat.lt_add_one_iff
theorem add_one_le_iff : ∀ {a b : ℕ+}, a + 1 ≤ b ↔ a < b := Nat.add_one_le_iff
#align pnat.add_one_le_iff PNat.add_one_le_iff
instance instOrderBot : OrderBot ℕ+ where
bot := 1
bot_le a := a.property
@[simp]
theorem bot_eq_one : (⊥ : ℕ+) = 1 :=
rfl
#align pnat.bot_eq_one PNat.bot_eq_one
def caseStrongInductionOn {p : ℕ+ → Sort*} (a : ℕ+) (hz : p 1)
(hi : ∀ n, (∀ m, m ≤ n → p m) → p (n + 1)) : p a := by
apply strongInductionOn a
rintro ⟨k, kprop⟩ hk
cases' k with k
· exact (lt_irrefl 0 kprop).elim
cases' k with k
· exact hz
exact hi ⟨k.succ, Nat.succ_pos _⟩ fun m hm => hk _ (Nat.lt_succ_iff.2 hm)
#align pnat.case_strong_induction_on PNat.caseStrongInductionOn
@[elab_as_elim]
def recOn (n : ℕ+) {p : ℕ+ → Sort*} (p1 : p 1) (hp : ∀ n, p n → p (n + 1)) : p n := by
rcases n with ⟨n, h⟩
induction' n with n IH
· exact absurd h (by decide)
· cases' n with n
· exact p1
· exact hp _ (IH n.succ_pos)
#align pnat.rec_on PNat.recOn
@[simp]
theorem recOn_one {p} (p1 hp) : @PNat.recOn 1 p p1 hp = p1 :=
rfl
#align pnat.rec_on_one PNat.recOn_one
@[simp]
theorem recOn_succ (n : ℕ+) {p : ℕ+ → Sort*} (p1 hp) :
@PNat.recOn (n + 1) p p1 hp = hp n (@PNat.recOn n p p1 hp) := by
cases' n with n h
cases n <;> [exact absurd h (by decide); rfl]
#align pnat.rec_on_succ PNat.recOn_succ
-- Porting note (#11229): deprecated
@[simp, norm_cast]
theorem mul_coe (m n : ℕ+) : ((m * n : ℕ+) : ℕ) = m * n :=
rfl
#align pnat.mul_coe PNat.mul_coe
def coeMonoidHom : ℕ+ →* ℕ where
toFun := Coe.coe
map_one' := one_coe
map_mul' := mul_coe
#align pnat.coe_monoid_hom PNat.coeMonoidHom
@[simp]
theorem coe_coeMonoidHom : (coeMonoidHom : ℕ+ → ℕ) = Coe.coe :=
rfl
#align pnat.coe_coe_monoid_hom PNat.coe_coeMonoidHom
@[simp]
theorem le_one_iff {n : ℕ+} : n ≤ 1 ↔ n = 1 :=
le_bot_iff
#align pnat.le_one_iff PNat.le_one_iff
theorem lt_add_left (n m : ℕ+) : n < m + n :=
lt_add_of_pos_left _ m.2
#align pnat.lt_add_left PNat.lt_add_left
theorem lt_add_right (n m : ℕ+) : n < n + m :=
(lt_add_left n m).trans_eq (add_comm _ _)
#align pnat.lt_add_right PNat.lt_add_right
@[simp, norm_cast]
theorem pow_coe (m : ℕ+) (n : ℕ) : ↑(m ^ n) = (m : ℕ) ^ n :=
rfl
#align pnat.pow_coe PNat.pow_coe
theorem one_lt_of_lt {a b : ℕ+} (hab : a < b) : 1 < b := bot_le.trans_lt hab
theorem add_one (a : ℕ+) : a + 1 = succPNat a := rfl
theorem lt_succ_self (a : ℕ+) : a < succPNat a := lt.base a
instance instSub : Sub ℕ+ :=
⟨fun a b => toPNat' (a - b : ℕ)⟩
theorem sub_coe (a b : ℕ+) : ((a - b : ℕ+) : ℕ) = ite (b < a) (a - b : ℕ) 1 := by
change (toPNat' _ : ℕ) = ite _ _ _
split_ifs with h
· exact toPNat'_coe (tsub_pos_of_lt h)
· rw [tsub_eq_zero_iff_le.mpr (le_of_not_gt h : (a : ℕ) ≤ b)]
rfl
#align pnat.sub_coe PNat.sub_coe
theorem sub_le (a b : ℕ+) : a - b ≤ a := by
rw [← coe_le_coe, sub_coe]
split_ifs with h
· exact Nat.sub_le a b
· exact a.2
theorem le_sub_one_of_lt {a b : ℕ+} (hab: a < b) : a ≤ b - (1 : ℕ+) := by
rw [← coe_le_coe, sub_coe]
split_ifs with h
· exact Nat.le_pred_of_lt hab
· exact hab.le.trans (le_of_not_lt h)
theorem add_sub_of_lt {a b : ℕ+} : a < b → a + (b - a) = b :=
fun h =>
PNat.eq <| by
rw [add_coe, sub_coe, if_pos h]
exact add_tsub_cancel_of_le h.le
#align pnat.add_sub_of_lt PNat.add_sub_of_lt
theorem exists_eq_succ_of_ne_one : ∀ {n : ℕ+} (_ : n ≠ 1), ∃ k : ℕ+, n = k + 1
| ⟨1, _⟩, h₁ => False.elim <| h₁ rfl
| ⟨n + 2, _⟩, _ => ⟨⟨n + 1, by simp⟩, rfl⟩
#align pnat.exists_eq_succ_of_ne_one PNat.exists_eq_succ_of_ne_one
theorem modDivAux_spec :
∀ (k : ℕ+) (r q : ℕ) (_ : ¬(r = 0 ∧ q = 0)),
((modDivAux k r q).1 : ℕ) + k * (modDivAux k r q).2 = r + k * q
| k, 0, 0, h => (h ⟨rfl, rfl⟩).elim
| k, 0, q + 1, _ => by
change (k : ℕ) + (k : ℕ) * (q + 1).pred = 0 + (k : ℕ) * (q + 1)
rw [Nat.pred_succ, Nat.mul_succ, zero_add, add_comm]
| k, r + 1, q, _ => rfl
#align pnat.mod_div_aux_spec PNat.modDivAux_spec
theorem mod_add_div (m k : ℕ+) : (mod m k + k * div m k : ℕ) = m := by
let h₀ := Nat.mod_add_div (m : ℕ) (k : ℕ)
have : ¬((m : ℕ) % (k : ℕ) = 0 ∧ (m : ℕ) / (k : ℕ) = 0) := by
rintro ⟨hr, hq⟩
rw [hr, hq, mul_zero, zero_add] at h₀
exact (m.ne_zero h₀.symm).elim
have := modDivAux_spec k ((m : ℕ) % (k : ℕ)) ((m : ℕ) / (k : ℕ)) this
exact this.trans h₀
#align pnat.mod_add_div PNat.mod_add_div
theorem div_add_mod (m k : ℕ+) : (k * div m k + mod m k : ℕ) = m :=
(add_comm _ _).trans (mod_add_div _ _)
#align pnat.div_add_mod PNat.div_add_mod
theorem mod_add_div' (m k : ℕ+) : (mod m k + div m k * k : ℕ) = m := by
rw [mul_comm]
exact mod_add_div _ _
#align pnat.mod_add_div' PNat.mod_add_div'
theorem div_add_mod' (m k : ℕ+) : (div m k * k + mod m k : ℕ) = m := by
rw [mul_comm]
exact div_add_mod _ _
#align pnat.div_add_mod' PNat.div_add_mod'
theorem mod_le (m k : ℕ+) : mod m k ≤ m ∧ mod m k ≤ k := by
change (mod m k : ℕ) ≤ (m : ℕ) ∧ (mod m k : ℕ) ≤ (k : ℕ)
rw [mod_coe]
split_ifs with h
· have hm : (m : ℕ) > 0 := m.pos
rw [← Nat.mod_add_div (m : ℕ) (k : ℕ), h, zero_add] at hm ⊢
by_cases h₁ : (m : ℕ) / (k : ℕ) = 0
· rw [h₁, mul_zero] at hm
exact (lt_irrefl _ hm).elim
· let h₂ : (k : ℕ) * 1 ≤ k * (m / k) :=
-- Porting note: Specified type of `h₂` explicitly because `rw` could not unify
-- `succ 0` with `1`.
Nat.mul_le_mul_left (k : ℕ) (Nat.succ_le_of_lt (Nat.pos_of_ne_zero h₁))
rw [mul_one] at h₂
exact ⟨h₂, le_refl (k : ℕ)⟩
· exact ⟨Nat.mod_le (m : ℕ) (k : ℕ), (Nat.mod_lt (m : ℕ) k.pos).le⟩
#align pnat.mod_le PNat.mod_le
theorem dvd_iff {k m : ℕ+} : k ∣ m ↔ (k : ℕ) ∣ (m : ℕ) := by
constructor <;> intro h
· rcases h with ⟨_, rfl⟩
apply dvd_mul_right
· rcases h with ⟨a, h⟩
obtain ⟨n, rfl⟩ := Nat.exists_eq_succ_of_ne_zero (n := a) <| by
rintro rfl
simp only [mul_zero, ne_zero] at h
use ⟨n.succ, n.succ_pos⟩
rw [← coe_inj, h, mul_coe, mk_coe]
#align pnat.dvd_iff PNat.dvd_iff
theorem dvd_iff' {k m : ℕ+} : k ∣ m ↔ mod m k = k := by
rw [dvd_iff]
rw [Nat.dvd_iff_mod_eq_zero]; constructor
· intro h
apply PNat.eq
rw [mod_coe, if_pos h]
· intro h
by_cases h' : (m : ℕ) % (k : ℕ) = 0
· exact h'
· replace h : (mod m k : ℕ) = (k : ℕ) := congr_arg _ h
rw [mod_coe, if_neg h'] at h
exact ((Nat.mod_lt (m : ℕ) k.pos).ne h).elim
#align pnat.dvd_iff' PNat.dvd_iff'
theorem le_of_dvd {m n : ℕ+} : m ∣ n → m ≤ n := by
rw [dvd_iff']
intro h
rw [← h]
apply (mod_le n m).left
#align pnat.le_of_dvd PNat.le_of_dvd
| Mathlib/Data/PNat/Basic.lean | 427 | 430 | theorem mul_div_exact {m k : ℕ+} (h : k ∣ m) : k * divExact m k = m := by |
apply PNat.eq; rw [mul_coe]
change (k : ℕ) * (div m k).succ = m
rw [← div_add_mod m k, dvd_iff'.mp h, Nat.mul_succ]
|
import Mathlib.CategoryTheory.Adjunction.FullyFaithful
import Mathlib.CategoryTheory.Conj
import Mathlib.CategoryTheory.Functor.ReflectsIso
#align_import category_theory.adjunction.reflective from "leanprover-community/mathlib"@"239d882c4fb58361ee8b3b39fb2091320edef10a"
universe v₁ v₂ v₃ u₁ u₂ u₃
noncomputable section
namespace CategoryTheory
open Category Adjunction
variable {C : Type u₁} {D : Type u₂} {E : Type u₃}
variable [Category.{v₁} C] [Category.{v₂} D] [Category.{v₃} E]
class Reflective (R : D ⥤ C) extends R.Full, R.Faithful where
L : C ⥤ D
adj : L ⊣ R
#align category_theory.reflective CategoryTheory.Reflective
variable (i : D ⥤ C)
def reflector [Reflective i] : C ⥤ D := Reflective.L (R := i)
def reflectorAdjunction [Reflective i] : reflector i ⊣ i := Reflective.adj
instance [Reflective i] : i.IsRightAdjoint := ⟨_, ⟨reflectorAdjunction i⟩⟩
instance [Reflective i] : (reflector i).IsLeftAdjoint := ⟨_, ⟨reflectorAdjunction i⟩⟩
def Functor.fullyFaithfulOfReflective [Reflective i] : i.FullyFaithful :=
(reflectorAdjunction i).fullyFaithfulROfIsIsoCounit
-- TODO: This holds more generally for idempotent adjunctions, not just reflective adjunctions.
theorem unit_obj_eq_map_unit [Reflective i] (X : C) :
(reflectorAdjunction i).unit.app (i.obj ((reflector i).obj X)) =
i.map ((reflector i).map ((reflectorAdjunction i).unit.app X)) := by
rw [← cancel_mono (i.map ((reflectorAdjunction i).counit.app ((reflector i).obj X))),
← i.map_comp]
simp
#align category_theory.unit_obj_eq_map_unit CategoryTheory.unit_obj_eq_map_unit
example [Reflective i] {B : D} : IsIso ((reflectorAdjunction i).unit.app (i.obj B)) :=
inferInstance
variable {i}
theorem Functor.essImage.unit_isIso [Reflective i] {A : C} (h : A ∈ i.essImage) :
IsIso ((reflectorAdjunction i).unit.app A) := by
rwa [isIso_unit_app_iff_mem_essImage]
#align category_theory.functor.ess_image.unit_is_iso CategoryTheory.Functor.essImage.unit_isIso
theorem mem_essImage_of_unit_isIso {L : C ⥤ D} (adj : L ⊣ i) (A : C)
[IsIso (adj.unit.app A)] : A ∈ i.essImage :=
⟨L.obj A, ⟨(asIso (adj.unit.app A)).symm⟩⟩
#align category_theory.mem_ess_image_of_unit_is_iso CategoryTheory.mem_essImage_of_unit_isIso
theorem mem_essImage_of_unit_isSplitMono [Reflective i] {A : C}
[IsSplitMono ((reflectorAdjunction i).unit.app A)] : A ∈ i.essImage := by
let η : 𝟭 C ⟶ reflector i ⋙ i := (reflectorAdjunction i).unit
haveI : IsIso (η.app (i.obj ((reflector i).obj A))) :=
Functor.essImage.unit_isIso ((i.obj_mem_essImage _))
have : Epi (η.app A) := by
refine @epi_of_epi _ _ _ _ _ (retraction (η.app A)) (η.app A) ?_
rw [show retraction _ ≫ η.app A = _ from η.naturality (retraction (η.app A))]
apply epi_comp (η.app (i.obj ((reflector i).obj A)))
haveI := isIso_of_epi_of_isSplitMono (η.app A)
exact mem_essImage_of_unit_isIso (reflectorAdjunction i) A
#align category_theory.mem_ess_image_of_unit_is_split_mono CategoryTheory.mem_essImage_of_unit_isSplitMono
instance Reflective.comp (F : C ⥤ D) (G : D ⥤ E) [Reflective F] [Reflective G] :
Reflective (F ⋙ G) where
L := reflector G ⋙ reflector F
adj := (reflectorAdjunction G).comp (reflectorAdjunction F)
#align category_theory.reflective.comp CategoryTheory.Reflective.comp
def unitCompPartialBijectiveAux [Reflective i] (A : C) (B : D) :
(A ⟶ i.obj B) ≃ (i.obj ((reflector i).obj A) ⟶ i.obj B) :=
((reflectorAdjunction i).homEquiv _ _).symm.trans
(Functor.FullyFaithful.ofFullyFaithful i).homEquiv
#align category_theory.unit_comp_partial_bijective_aux CategoryTheory.unitCompPartialBijectiveAux
theorem unitCompPartialBijectiveAux_symm_apply [Reflective i] {A : C} {B : D}
(f : i.obj ((reflector i).obj A) ⟶ i.obj B) :
(unitCompPartialBijectiveAux _ _).symm f = (reflectorAdjunction i).unit.app A ≫ f := by
simp [unitCompPartialBijectiveAux]
#align category_theory.unit_comp_partial_bijective_aux_symm_apply CategoryTheory.unitCompPartialBijectiveAux_symm_apply
def unitCompPartialBijective [Reflective i] (A : C) {B : C} (hB : B ∈ i.essImage) :
(A ⟶ B) ≃ (i.obj ((reflector i).obj A) ⟶ B) :=
calc
(A ⟶ B) ≃ (A ⟶ i.obj (Functor.essImage.witness hB)) := Iso.homCongr (Iso.refl _) hB.getIso.symm
_ ≃ (i.obj _ ⟶ i.obj (Functor.essImage.witness hB)) := unitCompPartialBijectiveAux _ _
_ ≃ (i.obj ((reflector i).obj A) ⟶ B) :=
Iso.homCongr (Iso.refl _) (Functor.essImage.getIso hB)
#align category_theory.unit_comp_partial_bijective CategoryTheory.unitCompPartialBijective
@[simp]
theorem unitCompPartialBijective_symm_apply [Reflective i] (A : C) {B : C} (hB : B ∈ i.essImage)
(f) : (unitCompPartialBijective A hB).symm f = (reflectorAdjunction i).unit.app A ≫ f := by
simp [unitCompPartialBijective, unitCompPartialBijectiveAux_symm_apply]
#align category_theory.unit_comp_partial_bijective_symm_apply CategoryTheory.unitCompPartialBijective_symm_apply
theorem unitCompPartialBijective_symm_natural [Reflective i] (A : C) {B B' : C} (h : B ⟶ B')
(hB : B ∈ i.essImage) (hB' : B' ∈ i.essImage) (f : i.obj ((reflector i).obj A) ⟶ B) :
(unitCompPartialBijective A hB').symm (f ≫ h) = (unitCompPartialBijective A hB).symm f ≫ h := by
simp
#align category_theory.unit_comp_partial_bijective_symm_natural CategoryTheory.unitCompPartialBijective_symm_natural
| Mathlib/CategoryTheory/Adjunction/Reflective.lean | 165 | 168 | theorem unitCompPartialBijective_natural [Reflective i] (A : C) {B B' : C} (h : B ⟶ B')
(hB : B ∈ i.essImage) (hB' : B' ∈ i.essImage) (f : A ⟶ B) :
(unitCompPartialBijective A hB') (f ≫ h) = unitCompPartialBijective A hB f ≫ h := by |
rw [← Equiv.eq_symm_apply, unitCompPartialBijective_symm_natural A h, Equiv.symm_apply_apply]
|
import Mathlib.Data.Finset.NAry
import Mathlib.Data.Finset.Slice
import Mathlib.Data.Set.Sups
#align_import data.finset.sups from "leanprover-community/mathlib"@"8818fdefc78642a7e6afcd20be5c184f3c7d9699"
#align finset.decidable_pred_mem_upper_closure instDecidablePredMemUpperClosure
#align finset.decidable_pred_mem_lower_closure instDecidablePredMemLowerClosure
open Function
open SetFamily
variable {F α β : Type*} [DecidableEq α] [DecidableEq β]
namespace Finset
open FinsetFamily
section DisjSups
variable [SemilatticeSup α] [OrderBot α] [@DecidableRel α Disjoint] (s s₁ s₂ t t₁ t₂ u : Finset α)
def disjSups : Finset α :=
((s ×ˢ t).filter fun ab : α × α => Disjoint ab.1 ab.2).image fun ab => ab.1 ⊔ ab.2
#align finset.disj_sups Finset.disjSups
@[inherit_doc]
scoped[FinsetFamily] infixl:74 " ○ " => Finset.disjSups
open FinsetFamily
variable {s t u} {a b c : α}
@[simp]
theorem mem_disjSups : c ∈ s ○ t ↔ ∃ a ∈ s, ∃ b ∈ t, Disjoint a b ∧ a ⊔ b = c := by
simp [disjSups, and_assoc]
#align finset.mem_disj_sups Finset.mem_disjSups
| Mathlib/Data/Finset/Sups.lean | 493 | 495 | theorem disjSups_subset_sups : s ○ t ⊆ s ⊻ t := by |
simp_rw [subset_iff, mem_sups, mem_disjSups]
exact fun c ⟨a, b, ha, hb, _, hc⟩ => ⟨a, b, ha, hb, hc⟩
|
import Mathlib.Data.List.Nodup
#align_import data.list.duplicate from "leanprover-community/mathlib"@"f694c7dead66f5d4c80f446c796a5aad14707f0e"
variable {α : Type*}
namespace List
inductive Duplicate (x : α) : List α → Prop
| cons_mem {l : List α} : x ∈ l → Duplicate x (x :: l)
| cons_duplicate {y : α} {l : List α} : Duplicate x l → Duplicate x (y :: l)
#align list.duplicate List.Duplicate
local infixl:50 " ∈+ " => List.Duplicate
variable {l : List α} {x : α}
theorem Mem.duplicate_cons_self (h : x ∈ l) : x ∈+ x :: l :=
Duplicate.cons_mem h
#align list.mem.duplicate_cons_self List.Mem.duplicate_cons_self
theorem Duplicate.duplicate_cons (h : x ∈+ l) (y : α) : x ∈+ y :: l :=
Duplicate.cons_duplicate h
#align list.duplicate.duplicate_cons List.Duplicate.duplicate_cons
theorem Duplicate.mem (h : x ∈+ l) : x ∈ l := by
induction' h with l' _ y l' _ hm
· exact mem_cons_self _ _
· exact mem_cons_of_mem _ hm
#align list.duplicate.mem List.Duplicate.mem
theorem Duplicate.mem_cons_self (h : x ∈+ x :: l) : x ∈ l := by
cases' h with _ h _ _ h
· exact h
· exact h.mem
#align list.duplicate.mem_cons_self List.Duplicate.mem_cons_self
@[simp]
theorem duplicate_cons_self_iff : x ∈+ x :: l ↔ x ∈ l :=
⟨Duplicate.mem_cons_self, Mem.duplicate_cons_self⟩
#align list.duplicate_cons_self_iff List.duplicate_cons_self_iff
theorem Duplicate.ne_nil (h : x ∈+ l) : l ≠ [] := fun H => (mem_nil_iff x).mp (H ▸ h.mem)
#align list.duplicate.ne_nil List.Duplicate.ne_nil
@[simp]
theorem not_duplicate_nil (x : α) : ¬x ∈+ [] := fun H => H.ne_nil rfl
#align list.not_duplicate_nil List.not_duplicate_nil
theorem Duplicate.ne_singleton (h : x ∈+ l) (y : α) : l ≠ [y] := by
induction' h with l' h z l' h _
· simp [ne_nil_of_mem h]
· simp [ne_nil_of_mem h.mem]
#align list.duplicate.ne_singleton List.Duplicate.ne_singleton
@[simp]
theorem not_duplicate_singleton (x y : α) : ¬x ∈+ [y] := fun H => H.ne_singleton _ rfl
#align list.not_duplicate_singleton List.not_duplicate_singleton
theorem Duplicate.elim_nil (h : x ∈+ []) : False :=
not_duplicate_nil x h
#align list.duplicate.elim_nil List.Duplicate.elim_nil
theorem Duplicate.elim_singleton {y : α} (h : x ∈+ [y]) : False :=
not_duplicate_singleton x y h
#align list.duplicate.elim_singleton List.Duplicate.elim_singleton
theorem duplicate_cons_iff {y : α} : x ∈+ y :: l ↔ y = x ∧ x ∈ l ∨ x ∈+ l := by
refine ⟨fun h => ?_, fun h => ?_⟩
· cases' h with _ hm _ _ hm
· exact Or.inl ⟨rfl, hm⟩
· exact Or.inr hm
· rcases h with (⟨rfl | h⟩ | h)
· simpa
· exact h.cons_duplicate
#align list.duplicate_cons_iff List.duplicate_cons_iff
theorem Duplicate.of_duplicate_cons {y : α} (h : x ∈+ y :: l) (hx : x ≠ y) : x ∈+ l := by
simpa [duplicate_cons_iff, hx.symm] using h
#align list.duplicate.of_duplicate_cons List.Duplicate.of_duplicate_cons
theorem duplicate_cons_iff_of_ne {y : α} (hne : x ≠ y) : x ∈+ y :: l ↔ x ∈+ l := by
simp [duplicate_cons_iff, hne.symm]
#align list.duplicate_cons_iff_of_ne List.duplicate_cons_iff_of_ne
| Mathlib/Data/List/Duplicate.lean | 106 | 113 | theorem Duplicate.mono_sublist {l' : List α} (hx : x ∈+ l) (h : l <+ l') : x ∈+ l' := by |
induction' h with l₁ l₂ y _ IH l₁ l₂ y h IH
· exact hx
· exact (IH hx).duplicate_cons _
· rw [duplicate_cons_iff] at hx ⊢
rcases hx with (⟨rfl, hx⟩ | hx)
· simp [h.subset hx]
· simp [IH hx]
|
import Mathlib.Algebra.BigOperators.GroupWithZero.Finset
import Mathlib.Data.Finite.Card
import Mathlib.GroupTheory.Finiteness
import Mathlib.GroupTheory.GroupAction.Quotient
#align_import group_theory.index from "leanprover-community/mathlib"@"dc6c365e751e34d100e80fe6e314c3c3e0fd2988"
namespace Subgroup
open Cardinal
variable {G : Type*} [Group G] (H K L : Subgroup G)
@[to_additive "The index of a subgroup as a natural number,
and returns 0 if the index is infinite."]
noncomputable def index : ℕ :=
Nat.card (G ⧸ H)
#align subgroup.index Subgroup.index
#align add_subgroup.index AddSubgroup.index
@[to_additive "The relative index of a subgroup as a natural number,
and returns 0 if the relative index is infinite."]
noncomputable def relindex : ℕ :=
(H.subgroupOf K).index
#align subgroup.relindex Subgroup.relindex
#align add_subgroup.relindex AddSubgroup.relindex
@[to_additive]
theorem index_comap_of_surjective {G' : Type*} [Group G'] {f : G' →* G}
(hf : Function.Surjective f) : (H.comap f).index = H.index := by
letI := QuotientGroup.leftRel H
letI := QuotientGroup.leftRel (H.comap f)
have key : ∀ x y : G', Setoid.r x y ↔ Setoid.r (f x) (f y) := by
simp only [QuotientGroup.leftRel_apply]
exact fun x y => iff_of_eq (congr_arg (· ∈ H) (by rw [f.map_mul, f.map_inv]))
refine Cardinal.toNat_congr (Equiv.ofBijective (Quotient.map' f fun x y => (key x y).mp) ⟨?_, ?_⟩)
· simp_rw [← Quotient.eq''] at key
refine Quotient.ind' fun x => ?_
refine Quotient.ind' fun y => ?_
exact (key x y).mpr
· refine Quotient.ind' fun x => ?_
obtain ⟨y, hy⟩ := hf x
exact ⟨y, (Quotient.map'_mk'' f _ y).trans (congr_arg Quotient.mk'' hy)⟩
#align subgroup.index_comap_of_surjective Subgroup.index_comap_of_surjective
#align add_subgroup.index_comap_of_surjective AddSubgroup.index_comap_of_surjective
@[to_additive]
theorem index_comap {G' : Type*} [Group G'] (f : G' →* G) :
(H.comap f).index = H.relindex f.range :=
Eq.trans (congr_arg index (by rfl))
((H.subgroupOf f.range).index_comap_of_surjective f.rangeRestrict_surjective)
#align subgroup.index_comap Subgroup.index_comap
#align add_subgroup.index_comap AddSubgroup.index_comap
@[to_additive]
theorem relindex_comap {G' : Type*} [Group G'] (f : G' →* G) (K : Subgroup G') :
relindex (comap f H) K = relindex H (map f K) := by
rw [relindex, subgroupOf, comap_comap, index_comap, ← f.map_range, K.subtype_range]
#align subgroup.relindex_comap Subgroup.relindex_comap
#align add_subgroup.relindex_comap AddSubgroup.relindex_comap
variable {H K L}
@[to_additive relindex_mul_index]
theorem relindex_mul_index (h : H ≤ K) : H.relindex K * K.index = H.index :=
((mul_comm _ _).trans (Cardinal.toNat_mul _ _).symm).trans
(congr_arg Cardinal.toNat (Equiv.cardinal_eq (quotientEquivProdOfLE h))).symm
#align subgroup.relindex_mul_index Subgroup.relindex_mul_index
#align add_subgroup.relindex_mul_index AddSubgroup.relindex_mul_index
@[to_additive]
theorem index_dvd_of_le (h : H ≤ K) : K.index ∣ H.index :=
dvd_of_mul_left_eq (H.relindex K) (relindex_mul_index h)
#align subgroup.index_dvd_of_le Subgroup.index_dvd_of_le
#align add_subgroup.index_dvd_of_le AddSubgroup.index_dvd_of_le
@[to_additive]
theorem relindex_dvd_index_of_le (h : H ≤ K) : H.relindex K ∣ H.index :=
dvd_of_mul_right_eq K.index (relindex_mul_index h)
#align subgroup.relindex_dvd_index_of_le Subgroup.relindex_dvd_index_of_le
#align add_subgroup.relindex_dvd_index_of_le AddSubgroup.relindex_dvd_index_of_le
@[to_additive]
theorem relindex_subgroupOf (hKL : K ≤ L) :
(H.subgroupOf L).relindex (K.subgroupOf L) = H.relindex K :=
((index_comap (H.subgroupOf L) (inclusion hKL)).trans (congr_arg _ (inclusion_range hKL))).symm
#align subgroup.relindex_subgroup_of Subgroup.relindex_subgroupOf
#align add_subgroup.relindex_add_subgroup_of AddSubgroup.relindex_addSubgroupOf
variable (H K L)
@[to_additive relindex_mul_relindex]
theorem relindex_mul_relindex (hHK : H ≤ K) (hKL : K ≤ L) :
H.relindex K * K.relindex L = H.relindex L := by
rw [← relindex_subgroupOf hKL]
exact relindex_mul_index fun x hx => hHK hx
#align subgroup.relindex_mul_relindex Subgroup.relindex_mul_relindex
#align add_subgroup.relindex_mul_relindex AddSubgroup.relindex_mul_relindex
@[to_additive]
theorem inf_relindex_right : (H ⊓ K).relindex K = H.relindex K := by
rw [relindex, relindex, inf_subgroupOf_right]
#align subgroup.inf_relindex_right Subgroup.inf_relindex_right
#align add_subgroup.inf_relindex_right AddSubgroup.inf_relindex_right
@[to_additive]
theorem inf_relindex_left : (H ⊓ K).relindex H = K.relindex H := by
rw [inf_comm, inf_relindex_right]
#align subgroup.inf_relindex_left Subgroup.inf_relindex_left
#align add_subgroup.inf_relindex_left AddSubgroup.inf_relindex_left
@[to_additive relindex_inf_mul_relindex]
theorem relindex_inf_mul_relindex : H.relindex (K ⊓ L) * K.relindex L = (H ⊓ K).relindex L := by
rw [← inf_relindex_right H (K ⊓ L), ← inf_relindex_right K L, ← inf_relindex_right (H ⊓ K) L,
inf_assoc, relindex_mul_relindex (H ⊓ (K ⊓ L)) (K ⊓ L) L inf_le_right inf_le_right]
#align subgroup.relindex_inf_mul_relindex Subgroup.relindex_inf_mul_relindex
#align add_subgroup.relindex_inf_mul_relindex AddSubgroup.relindex_inf_mul_relindex
@[to_additive (attr := simp)]
theorem relindex_sup_right [K.Normal] : K.relindex (H ⊔ K) = K.relindex H :=
Nat.card_congr (QuotientGroup.quotientInfEquivProdNormalQuotient H K).toEquiv.symm
#align subgroup.relindex_sup_right Subgroup.relindex_sup_right
#align add_subgroup.relindex_sup_right AddSubgroup.relindex_sup_right
@[to_additive (attr := simp)]
theorem relindex_sup_left [K.Normal] : K.relindex (K ⊔ H) = K.relindex H := by
rw [sup_comm, relindex_sup_right]
#align subgroup.relindex_sup_left Subgroup.relindex_sup_left
#align add_subgroup.relindex_sup_left AddSubgroup.relindex_sup_left
@[to_additive]
theorem relindex_dvd_index_of_normal [H.Normal] : H.relindex K ∣ H.index :=
relindex_sup_right K H ▸ relindex_dvd_index_of_le le_sup_right
#align subgroup.relindex_dvd_index_of_normal Subgroup.relindex_dvd_index_of_normal
#align add_subgroup.relindex_dvd_index_of_normal AddSubgroup.relindex_dvd_index_of_normal
variable {H K}
@[to_additive]
theorem relindex_dvd_of_le_left (hHK : H ≤ K) : K.relindex L ∣ H.relindex L :=
inf_of_le_left hHK ▸ dvd_of_mul_left_eq _ (relindex_inf_mul_relindex _ _ _)
#align subgroup.relindex_dvd_of_le_left Subgroup.relindex_dvd_of_le_left
#align add_subgroup.relindex_dvd_of_le_left AddSubgroup.relindex_dvd_of_le_left
@[to_additive "An additive subgroup has index two if and only if there exists `a` such that
for all `b`, exactly one of `b + a` and `b` belong to `H`."]
theorem index_eq_two_iff : H.index = 2 ↔ ∃ a, ∀ b, Xor' (b * a ∈ H) (b ∈ H) := by
simp only [index, Nat.card_eq_two_iff' ((1 : G) : G ⧸ H), ExistsUnique, inv_mem_iff,
QuotientGroup.exists_mk, QuotientGroup.forall_mk, Ne, QuotientGroup.eq, mul_one,
xor_iff_iff_not]
refine exists_congr fun a =>
⟨fun ha b => ⟨fun hba hb => ?_, fun hb => ?_⟩, fun ha => ⟨?_, fun b hb => ?_⟩⟩
· exact ha.1 ((mul_mem_cancel_left hb).1 hba)
· exact inv_inv b ▸ ha.2 _ (mt (inv_mem_iff (x := b)).1 hb)
· rw [← inv_mem_iff (x := a), ← ha, inv_mul_self]
exact one_mem _
· rwa [ha, inv_mem_iff (x := b)]
#align subgroup.index_eq_two_iff Subgroup.index_eq_two_iff
#align add_subgroup.index_eq_two_iff AddSubgroup.index_eq_two_iff
@[to_additive]
theorem mul_mem_iff_of_index_two (h : H.index = 2) {a b : G} : a * b ∈ H ↔ (a ∈ H ↔ b ∈ H) := by
by_cases ha : a ∈ H; · simp only [ha, true_iff_iff, mul_mem_cancel_left ha]
by_cases hb : b ∈ H; · simp only [hb, iff_true_iff, mul_mem_cancel_right hb]
simp only [ha, hb, iff_self_iff, iff_true_iff]
rcases index_eq_two_iff.1 h with ⟨c, hc⟩
refine (hc _).or.resolve_left ?_
rwa [mul_assoc, mul_mem_cancel_right ((hc _).or.resolve_right hb)]
#align subgroup.mul_mem_iff_of_index_two Subgroup.mul_mem_iff_of_index_two
#align add_subgroup.add_mem_iff_of_index_two AddSubgroup.add_mem_iff_of_index_two
@[to_additive]
theorem mul_self_mem_of_index_two (h : H.index = 2) (a : G) : a * a ∈ H := by
rw [mul_mem_iff_of_index_two h]
#align subgroup.mul_self_mem_of_index_two Subgroup.mul_self_mem_of_index_two
#align add_subgroup.add_self_mem_of_index_two AddSubgroup.add_self_mem_of_index_two
@[to_additive two_smul_mem_of_index_two]
theorem sq_mem_of_index_two (h : H.index = 2) (a : G) : a ^ 2 ∈ H :=
(pow_two a).symm ▸ mul_self_mem_of_index_two h a
#align subgroup.sq_mem_of_index_two Subgroup.sq_mem_of_index_two
#align add_subgroup.two_smul_mem_of_index_two AddSubgroup.two_smul_mem_of_index_two
variable (H K)
-- Porting note: had to replace `Cardinal.toNat_eq_one_iff_unique` with `Nat.card_eq_one_iff_unique`
@[to_additive (attr := simp)]
theorem index_top : (⊤ : Subgroup G).index = 1 :=
Nat.card_eq_one_iff_unique.mpr ⟨QuotientGroup.subsingleton_quotient_top, ⟨1⟩⟩
#align subgroup.index_top Subgroup.index_top
#align add_subgroup.index_top AddSubgroup.index_top
@[to_additive (attr := simp)]
theorem index_bot : (⊥ : Subgroup G).index = Nat.card G :=
Cardinal.toNat_congr QuotientGroup.quotientBot.toEquiv
#align subgroup.index_bot Subgroup.index_bot
#align add_subgroup.index_bot AddSubgroup.index_bot
@[to_additive]
theorem index_bot_eq_card [Fintype G] : (⊥ : Subgroup G).index = Fintype.card G :=
index_bot.trans Nat.card_eq_fintype_card
#align subgroup.index_bot_eq_card Subgroup.index_bot_eq_card
#align add_subgroup.index_bot_eq_card AddSubgroup.index_bot_eq_card
@[to_additive (attr := simp)]
theorem relindex_top_left : (⊤ : Subgroup G).relindex H = 1 :=
index_top
#align subgroup.relindex_top_left Subgroup.relindex_top_left
#align add_subgroup.relindex_top_left AddSubgroup.relindex_top_left
@[to_additive (attr := simp)]
theorem relindex_top_right : H.relindex ⊤ = H.index := by
rw [← relindex_mul_index (show H ≤ ⊤ from le_top), index_top, mul_one]
#align subgroup.relindex_top_right Subgroup.relindex_top_right
#align add_subgroup.relindex_top_right AddSubgroup.relindex_top_right
@[to_additive (attr := simp)]
theorem relindex_bot_left : (⊥ : Subgroup G).relindex H = Nat.card H := by
rw [relindex, bot_subgroupOf, index_bot]
#align subgroup.relindex_bot_left Subgroup.relindex_bot_left
#align add_subgroup.relindex_bot_left AddSubgroup.relindex_bot_left
@[to_additive]
theorem relindex_bot_left_eq_card [Fintype H] : (⊥ : Subgroup G).relindex H = Fintype.card H :=
H.relindex_bot_left.trans Nat.card_eq_fintype_card
#align subgroup.relindex_bot_left_eq_card Subgroup.relindex_bot_left_eq_card
#align add_subgroup.relindex_bot_left_eq_card AddSubgroup.relindex_bot_left_eq_card
@[to_additive (attr := simp)]
theorem relindex_bot_right : H.relindex ⊥ = 1 := by rw [relindex, subgroupOf_bot_eq_top, index_top]
#align subgroup.relindex_bot_right Subgroup.relindex_bot_right
#align add_subgroup.relindex_bot_right AddSubgroup.relindex_bot_right
@[to_additive (attr := simp)]
theorem relindex_self : H.relindex H = 1 := by rw [relindex, subgroupOf_self, index_top]
#align subgroup.relindex_self Subgroup.relindex_self
#align add_subgroup.relindex_self AddSubgroup.relindex_self
@[to_additive]
theorem index_ker {H} [Group H] (f : G →* H) : f.ker.index = Nat.card (Set.range f) := by
rw [← MonoidHom.comap_bot, index_comap, relindex_bot_left]
rfl
#align subgroup.index_ker Subgroup.index_ker
#align add_subgroup.index_ker AddSubgroup.index_ker
@[to_additive]
theorem relindex_ker {H} [Group H] (f : G →* H) (K : Subgroup G) :
f.ker.relindex K = Nat.card (f '' K) := by
rw [← MonoidHom.comap_bot, relindex_comap, relindex_bot_left]
rfl
#align subgroup.relindex_ker Subgroup.relindex_ker
#align add_subgroup.relindex_ker AddSubgroup.relindex_ker
@[to_additive (attr := simp) card_mul_index]
theorem card_mul_index : Nat.card H * H.index = Nat.card G := by
rw [← relindex_bot_left, ← index_bot]
exact relindex_mul_index bot_le
#align subgroup.card_mul_index Subgroup.card_mul_index
#align add_subgroup.card_mul_index AddSubgroup.card_mul_index
@[to_additive]
theorem nat_card_dvd_of_injective {G H : Type*} [Group G] [Group H] (f : G →* H)
(hf : Function.Injective f) : Nat.card G ∣ Nat.card H := by
rw [Nat.card_congr (MonoidHom.ofInjective hf).toEquiv]
exact Dvd.intro f.range.index f.range.card_mul_index
#align subgroup.nat_card_dvd_of_injective Subgroup.nat_card_dvd_of_injective
#align add_subgroup.nat_card_dvd_of_injective AddSubgroup.nat_card_dvd_of_injective
@[to_additive]
theorem nat_card_dvd_of_le (hHK : H ≤ K) : Nat.card H ∣ Nat.card K :=
nat_card_dvd_of_injective (inclusion hHK) (inclusion_injective hHK)
#align subgroup.nat_card_dvd_of_le Subgroup.nat_card_dvd_of_le
#align add_subgroup.nat_card_dvd_of_le AddSubgroup.nat_card_dvd_of_le
@[to_additive]
theorem nat_card_dvd_of_surjective {G H : Type*} [Group G] [Group H] (f : G →* H)
(hf : Function.Surjective f) : Nat.card H ∣ Nat.card G := by
rw [← Nat.card_congr (QuotientGroup.quotientKerEquivOfSurjective f hf).toEquiv]
exact Dvd.intro_left (Nat.card f.ker) f.ker.card_mul_index
#align subgroup.nat_card_dvd_of_surjective Subgroup.nat_card_dvd_of_surjective
#align add_subgroup.nat_card_dvd_of_surjective AddSubgroup.nat_card_dvd_of_surjective
@[to_additive]
| Mathlib/GroupTheory/Index.lean | 319 | 321 | theorem card_dvd_of_surjective {G H : Type*} [Group G] [Group H] [Fintype G] [Fintype H]
(f : G →* H) (hf : Function.Surjective f) : Fintype.card H ∣ Fintype.card G := by |
simp only [← Nat.card_eq_fintype_card, nat_card_dvd_of_surjective f hf]
|
import Mathlib.Algebra.Polynomial.Inductions
import Mathlib.Algebra.Polynomial.Monic
import Mathlib.RingTheory.Multiplicity
import Mathlib.RingTheory.Ideal.Maps
#align_import data.polynomial.div from "leanprover-community/mathlib"@"e1e7190efdcefc925cb36f257a8362ef22944204"
noncomputable section
open Polynomial
open Finset
namespace Polynomial
universe u v w z
variable {R : Type u} {S : Type v} {T : Type w} {A : Type z} {a b : R} {n : ℕ}
section Ring
variable [Ring R] {p q : R[X]}
theorem div_wf_lemma (h : degree q ≤ degree p ∧ p ≠ 0) (hq : Monic q) :
degree (p - q * (C (leadingCoeff p) * X ^ (natDegree p - natDegree q))) < degree p :=
have hp : leadingCoeff p ≠ 0 := mt leadingCoeff_eq_zero.1 h.2
have hq0 : q ≠ 0 := hq.ne_zero_of_polynomial_ne h.2
have hlt : natDegree q ≤ natDegree p :=
Nat.cast_le.1
(by rw [← degree_eq_natDegree h.2, ← degree_eq_natDegree hq0]; exact h.1)
degree_sub_lt
(by
rw [hq.degree_mul_comm, hq.degree_mul, degree_C_mul_X_pow _ hp, degree_eq_natDegree h.2,
degree_eq_natDegree hq0, ← Nat.cast_add, tsub_add_cancel_of_le hlt])
h.2 (by rw [leadingCoeff_monic_mul hq, leadingCoeff_mul_X_pow, leadingCoeff_C])
#align polynomial.div_wf_lemma Polynomial.div_wf_lemma
noncomputable def divModByMonicAux : ∀ (_p : R[X]) {q : R[X]}, Monic q → R[X] × R[X]
| p, q, hq =>
letI := Classical.decEq R
if h : degree q ≤ degree p ∧ p ≠ 0 then
let z := C (leadingCoeff p) * X ^ (natDegree p - natDegree q)
have _wf := div_wf_lemma h hq
let dm := divModByMonicAux (p - q * z) hq
⟨z + dm.1, dm.2⟩
else ⟨0, p⟩
termination_by p => p
#align polynomial.div_mod_by_monic_aux Polynomial.divModByMonicAux
def divByMonic (p q : R[X]) : R[X] :=
letI := Classical.decEq R
if hq : Monic q then (divModByMonicAux p hq).1 else 0
#align polynomial.div_by_monic Polynomial.divByMonic
def modByMonic (p q : R[X]) : R[X] :=
letI := Classical.decEq R
if hq : Monic q then (divModByMonicAux p hq).2 else p
#align polynomial.mod_by_monic Polynomial.modByMonic
@[inherit_doc]
infixl:70 " /ₘ " => divByMonic
@[inherit_doc]
infixl:70 " %ₘ " => modByMonic
theorem degree_modByMonic_lt [Nontrivial R] :
∀ (p : R[X]) {q : R[X]} (_hq : Monic q), degree (p %ₘ q) < degree q
| p, q, hq =>
letI := Classical.decEq R
if h : degree q ≤ degree p ∧ p ≠ 0 then by
have _wf := div_wf_lemma ⟨h.1, h.2⟩ hq
have :=
degree_modByMonic_lt (p - q * (C (leadingCoeff p) * X ^ (natDegree p - natDegree q))) hq
unfold modByMonic at this ⊢
unfold divModByMonicAux
dsimp
rw [dif_pos hq] at this ⊢
rw [if_pos h]
exact this
else
Or.casesOn (not_and_or.1 h)
(by
unfold modByMonic divModByMonicAux
dsimp
rw [dif_pos hq, if_neg h]
exact lt_of_not_ge)
(by
intro hp
unfold modByMonic divModByMonicAux
dsimp
rw [dif_pos hq, if_neg h, Classical.not_not.1 hp]
exact lt_of_le_of_ne bot_le (Ne.symm (mt degree_eq_bot.1 hq.ne_zero)))
termination_by p => p
#align polynomial.degree_mod_by_monic_lt Polynomial.degree_modByMonic_lt
theorem natDegree_modByMonic_lt (p : R[X]) {q : R[X]} (hmq : Monic q) (hq : q ≠ 1) :
natDegree (p %ₘ q) < q.natDegree := by
by_cases hpq : p %ₘ q = 0
· rw [hpq, natDegree_zero, Nat.pos_iff_ne_zero]
contrapose! hq
exact eq_one_of_monic_natDegree_zero hmq hq
· haveI := Nontrivial.of_polynomial_ne hpq
exact natDegree_lt_natDegree hpq (degree_modByMonic_lt p hmq)
@[simp]
theorem zero_modByMonic (p : R[X]) : 0 %ₘ p = 0 := by
classical
unfold modByMonic divModByMonicAux
dsimp
by_cases hp : Monic p
· rw [dif_pos hp, if_neg (mt And.right (not_not_intro rfl))]
· rw [dif_neg hp]
#align polynomial.zero_mod_by_monic Polynomial.zero_modByMonic
@[simp]
theorem zero_divByMonic (p : R[X]) : 0 /ₘ p = 0 := by
classical
unfold divByMonic divModByMonicAux
dsimp
by_cases hp : Monic p
· rw [dif_pos hp, if_neg (mt And.right (not_not_intro rfl))]
· rw [dif_neg hp]
#align polynomial.zero_div_by_monic Polynomial.zero_divByMonic
@[simp]
theorem modByMonic_zero (p : R[X]) : p %ₘ 0 = p :=
letI := Classical.decEq R
if h : Monic (0 : R[X]) then by
haveI := monic_zero_iff_subsingleton.mp h
simp [eq_iff_true_of_subsingleton]
else by unfold modByMonic divModByMonicAux; rw [dif_neg h]
#align polynomial.mod_by_monic_zero Polynomial.modByMonic_zero
@[simp]
theorem divByMonic_zero (p : R[X]) : p /ₘ 0 = 0 :=
letI := Classical.decEq R
if h : Monic (0 : R[X]) then by
haveI := monic_zero_iff_subsingleton.mp h
simp [eq_iff_true_of_subsingleton]
else by unfold divByMonic divModByMonicAux; rw [dif_neg h]
#align polynomial.div_by_monic_zero Polynomial.divByMonic_zero
theorem divByMonic_eq_of_not_monic (p : R[X]) (hq : ¬Monic q) : p /ₘ q = 0 :=
dif_neg hq
#align polynomial.div_by_monic_eq_of_not_monic Polynomial.divByMonic_eq_of_not_monic
theorem modByMonic_eq_of_not_monic (p : R[X]) (hq : ¬Monic q) : p %ₘ q = p :=
dif_neg hq
#align polynomial.mod_by_monic_eq_of_not_monic Polynomial.modByMonic_eq_of_not_monic
theorem modByMonic_eq_self_iff [Nontrivial R] (hq : Monic q) : p %ₘ q = p ↔ degree p < degree q :=
⟨fun h => h ▸ degree_modByMonic_lt _ hq, fun h => by
classical
have : ¬degree q ≤ degree p := not_le_of_gt h
unfold modByMonic divModByMonicAux; dsimp; rw [dif_pos hq, if_neg (mt And.left this)]⟩
#align polynomial.mod_by_monic_eq_self_iff Polynomial.modByMonic_eq_self_iff
theorem degree_modByMonic_le (p : R[X]) {q : R[X]} (hq : Monic q) : degree (p %ₘ q) ≤ degree q := by
nontriviality R
exact (degree_modByMonic_lt _ hq).le
#align polynomial.degree_mod_by_monic_le Polynomial.degree_modByMonic_le
theorem natDegree_modByMonic_le (p : Polynomial R) {g : Polynomial R} (hg : g.Monic) :
natDegree (p %ₘ g) ≤ g.natDegree :=
natDegree_le_natDegree (degree_modByMonic_le p hg)
theorem X_dvd_sub_C : X ∣ p - C (p.coeff 0) := by
simp [X_dvd_iff, coeff_C]
theorem modByMonic_eq_sub_mul_div :
∀ (p : R[X]) {q : R[X]} (_hq : Monic q), p %ₘ q = p - q * (p /ₘ q)
| p, q, hq =>
letI := Classical.decEq R
if h : degree q ≤ degree p ∧ p ≠ 0 then by
have _wf := div_wf_lemma h hq
have ih := modByMonic_eq_sub_mul_div
(p - q * (C (leadingCoeff p) * X ^ (natDegree p - natDegree q))) hq
unfold modByMonic divByMonic divModByMonicAux
dsimp
rw [dif_pos hq, if_pos h]
rw [modByMonic, dif_pos hq] at ih
refine ih.trans ?_
unfold divByMonic
rw [dif_pos hq, dif_pos hq, if_pos h, mul_add, sub_add_eq_sub_sub]
else by
unfold modByMonic divByMonic divModByMonicAux
dsimp
rw [dif_pos hq, if_neg h, dif_pos hq, if_neg h, mul_zero, sub_zero]
termination_by p => p
#align polynomial.mod_by_monic_eq_sub_mul_div Polynomial.modByMonic_eq_sub_mul_div
theorem modByMonic_add_div (p : R[X]) {q : R[X]} (hq : Monic q) : p %ₘ q + q * (p /ₘ q) = p :=
eq_sub_iff_add_eq.1 (modByMonic_eq_sub_mul_div p hq)
#align polynomial.mod_by_monic_add_div Polynomial.modByMonic_add_div
theorem divByMonic_eq_zero_iff [Nontrivial R] (hq : Monic q) : p /ₘ q = 0 ↔ degree p < degree q :=
⟨fun h => by
have := modByMonic_add_div p hq;
rwa [h, mul_zero, add_zero, modByMonic_eq_self_iff hq] at this,
fun h => by
classical
have : ¬degree q ≤ degree p := not_le_of_gt h
unfold divByMonic divModByMonicAux; dsimp; rw [dif_pos hq, if_neg (mt And.left this)]⟩
#align polynomial.div_by_monic_eq_zero_iff Polynomial.divByMonic_eq_zero_iff
theorem degree_add_divByMonic (hq : Monic q) (h : degree q ≤ degree p) :
degree q + degree (p /ₘ q) = degree p := by
nontriviality R
have hdiv0 : p /ₘ q ≠ 0 := by rwa [Ne, divByMonic_eq_zero_iff hq, not_lt]
have hlc : leadingCoeff q * leadingCoeff (p /ₘ q) ≠ 0 := by
rwa [Monic.def.1 hq, one_mul, Ne, leadingCoeff_eq_zero]
have hmod : degree (p %ₘ q) < degree (q * (p /ₘ q)) :=
calc
degree (p %ₘ q) < degree q := degree_modByMonic_lt _ hq
_ ≤ _ := by
rw [degree_mul' hlc, degree_eq_natDegree hq.ne_zero, degree_eq_natDegree hdiv0, ←
Nat.cast_add, Nat.cast_le]
exact Nat.le_add_right _ _
calc
degree q + degree (p /ₘ q) = degree (q * (p /ₘ q)) := Eq.symm (degree_mul' hlc)
_ = degree (p %ₘ q + q * (p /ₘ q)) := (degree_add_eq_right_of_degree_lt hmod).symm
_ = _ := congr_arg _ (modByMonic_add_div _ hq)
#align polynomial.degree_add_div_by_monic Polynomial.degree_add_divByMonic
theorem degree_divByMonic_le (p q : R[X]) : degree (p /ₘ q) ≤ degree p :=
letI := Classical.decEq R
if hp0 : p = 0 then by simp only [hp0, zero_divByMonic, le_refl]
else
if hq : Monic q then
if h : degree q ≤ degree p then by
haveI := Nontrivial.of_polynomial_ne hp0;
rw [← degree_add_divByMonic hq h, degree_eq_natDegree hq.ne_zero,
degree_eq_natDegree (mt (divByMonic_eq_zero_iff hq).1 (not_lt.2 h))];
exact WithBot.coe_le_coe.2 (Nat.le_add_left _ _)
else by
unfold divByMonic divModByMonicAux;
simp [dif_pos hq, h, false_and_iff, if_false, degree_zero, bot_le]
else (divByMonic_eq_of_not_monic p hq).symm ▸ bot_le
#align polynomial.degree_div_by_monic_le Polynomial.degree_divByMonic_le
theorem degree_divByMonic_lt (p : R[X]) {q : R[X]} (hq : Monic q) (hp0 : p ≠ 0)
(h0q : 0 < degree q) : degree (p /ₘ q) < degree p :=
if hpq : degree p < degree q then by
haveI := Nontrivial.of_polynomial_ne hp0
rw [(divByMonic_eq_zero_iff hq).2 hpq, degree_eq_natDegree hp0]
exact WithBot.bot_lt_coe _
else by
haveI := Nontrivial.of_polynomial_ne hp0
rw [← degree_add_divByMonic hq (not_lt.1 hpq), degree_eq_natDegree hq.ne_zero,
degree_eq_natDegree (mt (divByMonic_eq_zero_iff hq).1 hpq)]
exact
Nat.cast_lt.2
(Nat.lt_add_of_pos_left (Nat.cast_lt.1 <|
by simpa [degree_eq_natDegree hq.ne_zero] using h0q))
#align polynomial.degree_div_by_monic_lt Polynomial.degree_divByMonic_lt
theorem natDegree_divByMonic (f : R[X]) {g : R[X]} (hg : g.Monic) :
natDegree (f /ₘ g) = natDegree f - natDegree g := by
nontriviality R
by_cases hfg : f /ₘ g = 0
· rw [hfg, natDegree_zero]
rw [divByMonic_eq_zero_iff hg] at hfg
rw [tsub_eq_zero_iff_le.mpr (natDegree_le_natDegree <| le_of_lt hfg)]
have hgf := hfg
rw [divByMonic_eq_zero_iff hg] at hgf
push_neg at hgf
have := degree_add_divByMonic hg hgf
have hf : f ≠ 0 := by
intro hf
apply hfg
rw [hf, zero_divByMonic]
rw [degree_eq_natDegree hf, degree_eq_natDegree hg.ne_zero, degree_eq_natDegree hfg,
← Nat.cast_add, Nat.cast_inj] at this
rw [← this, add_tsub_cancel_left]
#align polynomial.nat_degree_div_by_monic Polynomial.natDegree_divByMonic
| Mathlib/Algebra/Polynomial/Div.lean | 347 | 368 | theorem div_modByMonic_unique {f g} (q r : R[X]) (hg : Monic g)
(h : r + g * q = f ∧ degree r < degree g) : f /ₘ g = q ∧ f %ₘ g = r := by |
nontriviality R
have h₁ : r - f %ₘ g = -g * (q - f /ₘ g) :=
eq_of_sub_eq_zero
(by
rw [← sub_eq_zero_of_eq (h.1.trans (modByMonic_add_div f hg).symm)]
simp [mul_add, mul_comm, sub_eq_add_neg, add_comm, add_left_comm, add_assoc])
have h₂ : degree (r - f %ₘ g) = degree (g * (q - f /ₘ g)) := by simp [h₁]
have h₄ : degree (r - f %ₘ g) < degree g :=
calc
degree (r - f %ₘ g) ≤ max (degree r) (degree (f %ₘ g)) := degree_sub_le _ _
_ < degree g := max_lt_iff.2 ⟨h.2, degree_modByMonic_lt _ hg⟩
have h₅ : q - f /ₘ g = 0 :=
_root_.by_contradiction fun hqf =>
not_le_of_gt h₄ <|
calc
degree g ≤ degree g + degree (q - f /ₘ g) := by
erw [degree_eq_natDegree hg.ne_zero, degree_eq_natDegree hqf, WithBot.coe_le_coe]
exact Nat.le_add_right _ _
_ = degree (r - f %ₘ g) := by rw [h₂, degree_mul']; simpa [Monic.def.1 hg]
exact ⟨Eq.symm <| eq_of_sub_eq_zero h₅, Eq.symm <| eq_of_sub_eq_zero <| by simpa [h₅] using h₁⟩
|
import Mathlib.Algebra.Algebra.Opposite
import Mathlib.Algebra.Algebra.Pi
import Mathlib.Algebra.BigOperators.Pi
import Mathlib.Algebra.BigOperators.Ring
import Mathlib.Algebra.BigOperators.RingEquiv
import Mathlib.Algebra.Module.LinearMap.Basic
import Mathlib.Algebra.Module.Pi
import Mathlib.Algebra.Star.BigOperators
import Mathlib.Algebra.Star.Module
import Mathlib.Algebra.Star.Pi
import Mathlib.Data.Fintype.BigOperators
import Mathlib.GroupTheory.GroupAction.BigOperators
#align_import data.matrix.basic from "leanprover-community/mathlib"@"eba5bb3155cab51d80af00e8d7d69fa271b1302b"
universe u u' v w
def Matrix (m : Type u) (n : Type u') (α : Type v) : Type max u u' v :=
m → n → α
#align matrix Matrix
variable {l m n o : Type*} {m' : o → Type*} {n' : o → Type*}
variable {R : Type*} {S : Type*} {α : Type v} {β : Type w} {γ : Type*}
namespace Matrix
open Matrix
namespace Matrix
section Diagonal
variable [DecidableEq n]
def diagonal [Zero α] (d : n → α) : Matrix n n α :=
of fun i j => if i = j then d i else 0
#align matrix.diagonal Matrix.diagonal
-- TODO: set as an equation lemma for `diagonal`, see mathlib4#3024
theorem diagonal_apply [Zero α] (d : n → α) (i j) : diagonal d i j = if i = j then d i else 0 :=
rfl
#align matrix.diagonal_apply Matrix.diagonal_apply
@[simp]
theorem diagonal_apply_eq [Zero α] (d : n → α) (i : n) : (diagonal d) i i = d i := by
simp [diagonal]
#align matrix.diagonal_apply_eq Matrix.diagonal_apply_eq
@[simp]
theorem diagonal_apply_ne [Zero α] (d : n → α) {i j : n} (h : i ≠ j) : (diagonal d) i j = 0 := by
simp [diagonal, h]
#align matrix.diagonal_apply_ne Matrix.diagonal_apply_ne
theorem diagonal_apply_ne' [Zero α] (d : n → α) {i j : n} (h : j ≠ i) : (diagonal d) i j = 0 :=
diagonal_apply_ne d h.symm
#align matrix.diagonal_apply_ne' Matrix.diagonal_apply_ne'
@[simp]
theorem diagonal_eq_diagonal_iff [Zero α] {d₁ d₂ : n → α} :
diagonal d₁ = diagonal d₂ ↔ ∀ i, d₁ i = d₂ i :=
⟨fun h i => by simpa using congr_arg (fun m : Matrix n n α => m i i) h, fun h => by
rw [show d₁ = d₂ from funext h]⟩
#align matrix.diagonal_eq_diagonal_iff Matrix.diagonal_eq_diagonal_iff
theorem diagonal_injective [Zero α] : Function.Injective (diagonal : (n → α) → Matrix n n α) :=
fun d₁ d₂ h => funext fun i => by simpa using Matrix.ext_iff.mpr h i i
#align matrix.diagonal_injective Matrix.diagonal_injective
@[simp]
theorem diagonal_zero [Zero α] : (diagonal fun _ => 0 : Matrix n n α) = 0 := by
ext
simp [diagonal]
#align matrix.diagonal_zero Matrix.diagonal_zero
@[simp]
theorem diagonal_transpose [Zero α] (v : n → α) : (diagonal v)ᵀ = diagonal v := by
ext i j
by_cases h : i = j
· simp [h, transpose]
· simp [h, transpose, diagonal_apply_ne' _ h]
#align matrix.diagonal_transpose Matrix.diagonal_transpose
@[simp]
theorem diagonal_add [AddZeroClass α] (d₁ d₂ : n → α) :
diagonal d₁ + diagonal d₂ = diagonal fun i => d₁ i + d₂ i := by
ext i j
by_cases h : i = j <;>
simp [h]
#align matrix.diagonal_add Matrix.diagonal_add
@[simp]
theorem diagonal_smul [Zero α] [SMulZeroClass R α] (r : R) (d : n → α) :
diagonal (r • d) = r • diagonal d := by
ext i j
by_cases h : i = j <;> simp [h]
#align matrix.diagonal_smul Matrix.diagonal_smul
@[simp]
theorem diagonal_neg [NegZeroClass α] (d : n → α) :
-diagonal d = diagonal fun i => -d i := by
ext i j
by_cases h : i = j <;>
simp [h]
#align matrix.diagonal_neg Matrix.diagonal_neg
@[simp]
theorem diagonal_sub [SubNegZeroMonoid α] (d₁ d₂ : n → α) :
diagonal d₁ - diagonal d₂ = diagonal fun i => d₁ i - d₂ i := by
ext i j
by_cases h : i = j <;>
simp [h]
instance [Zero α] [NatCast α] : NatCast (Matrix n n α) where
natCast m := diagonal fun _ => m
@[norm_cast]
theorem diagonal_natCast [Zero α] [NatCast α] (m : ℕ) : diagonal (fun _ : n => (m : α)) = m := rfl
@[norm_cast]
theorem diagonal_natCast' [Zero α] [NatCast α] (m : ℕ) : diagonal ((m : n → α)) = m := rfl
-- See note [no_index around OfNat.ofNat]
theorem diagonal_ofNat [Zero α] [NatCast α] (m : ℕ) [m.AtLeastTwo] :
diagonal (fun _ : n => no_index (OfNat.ofNat m : α)) = OfNat.ofNat m := rfl
-- See note [no_index around OfNat.ofNat]
theorem diagonal_ofNat' [Zero α] [NatCast α] (m : ℕ) [m.AtLeastTwo] :
diagonal (no_index (OfNat.ofNat m : n → α)) = OfNat.ofNat m := rfl
instance [Zero α] [IntCast α] : IntCast (Matrix n n α) where
intCast m := diagonal fun _ => m
@[norm_cast]
theorem diagonal_intCast [Zero α] [IntCast α] (m : ℤ) : diagonal (fun _ : n => (m : α)) = m := rfl
@[norm_cast]
theorem diagonal_intCast' [Zero α] [IntCast α] (m : ℤ) : diagonal ((m : n → α)) = m := rfl
variable (n α)
@[simps]
def diagonalAddMonoidHom [AddZeroClass α] : (n → α) →+ Matrix n n α where
toFun := diagonal
map_zero' := diagonal_zero
map_add' x y := (diagonal_add x y).symm
#align matrix.diagonal_add_monoid_hom Matrix.diagonalAddMonoidHom
variable (R)
@[simps]
def diagonalLinearMap [Semiring R] [AddCommMonoid α] [Module R α] : (n → α) →ₗ[R] Matrix n n α :=
{ diagonalAddMonoidHom n α with map_smul' := diagonal_smul }
#align matrix.diagonal_linear_map Matrix.diagonalLinearMap
variable {n α R}
@[simp]
theorem diagonal_map [Zero α] [Zero β] {f : α → β} (h : f 0 = 0) {d : n → α} :
(diagonal d).map f = diagonal fun m => f (d m) := by
ext
simp only [diagonal_apply, map_apply]
split_ifs <;> simp [h]
#align matrix.diagonal_map Matrix.diagonal_map
@[simp]
theorem diagonal_conjTranspose [AddMonoid α] [StarAddMonoid α] (v : n → α) :
(diagonal v)ᴴ = diagonal (star v) := by
rw [conjTranspose, diagonal_transpose, diagonal_map (star_zero _)]
rfl
#align matrix.diagonal_conj_transpose Matrix.diagonal_conjTranspose
instance instAddMonoidWithOne [AddMonoidWithOne α] : AddMonoidWithOne (Matrix n n α) where
natCast_zero := show diagonal _ = _ by
rw [Nat.cast_zero, diagonal_zero]
natCast_succ n := show diagonal _ = diagonal _ + _ by
rw [Nat.cast_succ, ← diagonal_add, diagonal_one]
instance instAddGroupWithOne [AddGroupWithOne α] : AddGroupWithOne (Matrix n n α) where
intCast_ofNat n := show diagonal _ = diagonal _ by
rw [Int.cast_natCast]
intCast_negSucc n := show diagonal _ = -(diagonal _) by
rw [Int.cast_negSucc, diagonal_neg]
__ := addGroup
__ := instAddMonoidWithOne
instance instAddCommMonoidWithOne [AddCommMonoidWithOne α] :
AddCommMonoidWithOne (Matrix n n α) where
__ := addCommMonoid
__ := instAddMonoidWithOne
instance instAddCommGroupWithOne [AddCommGroupWithOne α] :
AddCommGroupWithOne (Matrix n n α) where
__ := addCommGroup
__ := instAddGroupWithOne
section DotProduct
variable [Fintype m] [Fintype n]
def dotProduct [Mul α] [AddCommMonoid α] (v w : m → α) : α :=
∑ i, v i * w i
#align matrix.dot_product Matrix.dotProduct
@[inherit_doc]
scoped infixl:72 " ⬝ᵥ " => Matrix.dotProduct
theorem dotProduct_assoc [NonUnitalSemiring α] (u : m → α) (w : n → α) (v : Matrix m n α) :
(fun j => u ⬝ᵥ fun i => v i j) ⬝ᵥ w = u ⬝ᵥ fun i => v i ⬝ᵥ w := by
simpa [dotProduct, Finset.mul_sum, Finset.sum_mul, mul_assoc] using Finset.sum_comm
#align matrix.dot_product_assoc Matrix.dotProduct_assoc
theorem dotProduct_comm [AddCommMonoid α] [CommSemigroup α] (v w : m → α) : v ⬝ᵥ w = w ⬝ᵥ v := by
simp_rw [dotProduct, mul_comm]
#align matrix.dot_product_comm Matrix.dotProduct_comm
@[simp]
| Mathlib/Data/Matrix/Basic.lean | 762 | 763 | theorem dotProduct_pUnit [AddCommMonoid α] [Mul α] (v w : PUnit → α) : v ⬝ᵥ w = v ⟨⟩ * w ⟨⟩ := by |
simp [dotProduct]
|
import Mathlib.MeasureTheory.Integral.Lebesgue
#align_import measure_theory.measure.giry_monad from "leanprover-community/mathlib"@"56f4cd1ef396e9fd389b5d8371ee9ad91d163625"
noncomputable section
open scoped Classical
open ENNReal
open scoped Classical
open Set Filter
variable {α β : Type*}
namespace MeasureTheory
namespace Measure
variable [MeasurableSpace α] [MeasurableSpace β]
instance instMeasurableSpace : MeasurableSpace (Measure α) :=
⨆ (s : Set α) (_ : MeasurableSet s), (borel ℝ≥0∞).comap fun μ => μ s
#align measure_theory.measure.measurable_space MeasureTheory.Measure.instMeasurableSpace
theorem measurable_coe {s : Set α} (hs : MeasurableSet s) : Measurable fun μ : Measure α => μ s :=
Measurable.of_comap_le <| le_iSup_of_le s <| le_iSup_of_le hs <| le_rfl
#align measure_theory.measure.measurable_coe MeasureTheory.Measure.measurable_coe
theorem measurable_of_measurable_coe (f : β → Measure α)
(h : ∀ (s : Set α), MeasurableSet s → Measurable fun b => f b s) : Measurable f :=
Measurable.of_le_map <|
iSup₂_le fun s hs =>
MeasurableSpace.comap_le_iff_le_map.2 <| by rw [MeasurableSpace.map_comp]; exact h s hs
#align measure_theory.measure.measurable_of_measurable_coe MeasureTheory.Measure.measurable_of_measurable_coe
instance instMeasurableAdd₂ {α : Type*} {m : MeasurableSpace α} : MeasurableAdd₂ (Measure α) := by
refine ⟨Measure.measurable_of_measurable_coe _ fun s hs => ?_⟩
simp_rw [Measure.coe_add, Pi.add_apply]
refine Measurable.add ?_ ?_
· exact (Measure.measurable_coe hs).comp measurable_fst
· exact (Measure.measurable_coe hs).comp measurable_snd
#align measure_theory.measure.has_measurable_add₂ MeasureTheory.Measure.instMeasurableAdd₂
theorem measurable_measure {μ : α → Measure β} :
Measurable μ ↔ ∀ (s : Set β), MeasurableSet s → Measurable fun b => μ b s :=
⟨fun hμ _s hs => (measurable_coe hs).comp hμ, measurable_of_measurable_coe μ⟩
#align measure_theory.measure.measurable_measure MeasureTheory.Measure.measurable_measure
theorem measurable_map (f : α → β) (hf : Measurable f) :
Measurable fun μ : Measure α => map f μ := by
refine measurable_of_measurable_coe _ fun s hs => ?_
simp_rw [map_apply hf hs]
exact measurable_coe (hf hs)
#align measure_theory.measure.measurable_map MeasureTheory.Measure.measurable_map
theorem measurable_dirac : Measurable (Measure.dirac : α → Measure α) := by
refine measurable_of_measurable_coe _ fun s hs => ?_
simp_rw [dirac_apply' _ hs]
exact measurable_one.indicator hs
#align measure_theory.measure.measurable_dirac MeasureTheory.Measure.measurable_dirac
theorem measurable_lintegral {f : α → ℝ≥0∞} (hf : Measurable f) :
Measurable fun μ : Measure α => ∫⁻ x, f x ∂μ := by
simp only [lintegral_eq_iSup_eapprox_lintegral, hf, SimpleFunc.lintegral]
refine measurable_iSup fun n => Finset.measurable_sum _ fun i _ => ?_
refine Measurable.const_mul ?_ _
exact measurable_coe ((SimpleFunc.eapprox f n).measurableSet_preimage _)
#align measure_theory.measure.measurable_lintegral MeasureTheory.Measure.measurable_lintegral
def join (m : Measure (Measure α)) : Measure α :=
Measure.ofMeasurable (fun s _ => ∫⁻ μ, μ s ∂m)
(by simp only [measure_empty, lintegral_const, zero_mul])
(by
intro f hf h
simp_rw [measure_iUnion h hf]
apply lintegral_tsum
intro i; exact (measurable_coe (hf i)).aemeasurable)
#align measure_theory.measure.join MeasureTheory.Measure.join
@[simp]
theorem join_apply {m : Measure (Measure α)} {s : Set α} (hs : MeasurableSet s) :
join m s = ∫⁻ μ, μ s ∂m :=
Measure.ofMeasurable_apply s hs
#align measure_theory.measure.join_apply MeasureTheory.Measure.join_apply
@[simp]
theorem join_zero : (0 : Measure (Measure α)).join = 0 := by
ext1 s hs
simp only [hs, join_apply, lintegral_zero_measure, coe_zero, Pi.zero_apply]
#align measure_theory.measure.join_zero MeasureTheory.Measure.join_zero
theorem measurable_join : Measurable (join : Measure (Measure α) → Measure α) :=
measurable_of_measurable_coe _ fun s hs => by
simp only [join_apply hs]; exact measurable_lintegral (measurable_coe hs)
#align measure_theory.measure.measurable_join MeasureTheory.Measure.measurable_join
theorem lintegral_join {m : Measure (Measure α)} {f : α → ℝ≥0∞} (hf : Measurable f) :
∫⁻ x, f x ∂join m = ∫⁻ μ, ∫⁻ x, f x ∂μ ∂m := by
simp_rw [lintegral_eq_iSup_eapprox_lintegral hf, SimpleFunc.lintegral,
join_apply (SimpleFunc.measurableSet_preimage _ _)]
suffices
∀ (s : ℕ → Finset ℝ≥0∞) (f : ℕ → ℝ≥0∞ → Measure α → ℝ≥0∞), (∀ n r, Measurable (f n r)) →
Monotone (fun n μ => ∑ r ∈ s n, r * f n r μ) →
⨆ n, ∑ r ∈ s n, r * ∫⁻ μ, f n r μ ∂m = ∫⁻ μ, ⨆ n, ∑ r ∈ s n, r * f n r μ ∂m by
refine
this (fun n => SimpleFunc.range (SimpleFunc.eapprox f n))
(fun n r μ => μ (SimpleFunc.eapprox f n ⁻¹' {r})) ?_ ?_
· exact fun n r => measurable_coe (SimpleFunc.measurableSet_preimage _ _)
· exact fun n m h μ => SimpleFunc.lintegral_mono (SimpleFunc.monotone_eapprox _ h) le_rfl
intro s f hf hm
rw [lintegral_iSup _ hm]
swap
· exact fun n => Finset.measurable_sum _ fun r _ => (hf _ _).const_mul _
congr
funext n
rw [lintegral_finset_sum (s n)]
· simp_rw [lintegral_const_mul _ (hf _ _)]
· exact fun r _ => (hf _ _).const_mul _
#align measure_theory.measure.lintegral_join MeasureTheory.Measure.lintegral_join
def bind (m : Measure α) (f : α → Measure β) : Measure β :=
join (map f m)
#align measure_theory.measure.bind MeasureTheory.Measure.bind
@[simp]
theorem bind_zero_left (f : α → Measure β) : bind 0 f = 0 := by simp [bind]
#align measure_theory.measure.bind_zero_left MeasureTheory.Measure.bind_zero_left
@[simp]
| Mathlib/MeasureTheory/Measure/GiryMonad.lean | 163 | 167 | theorem bind_zero_right (m : Measure α) : bind m (0 : α → Measure β) = 0 := by |
ext1 s hs
simp only [bind, hs, join_apply, coe_zero, Pi.zero_apply]
rw [lintegral_map (measurable_coe hs) measurable_zero]
simp only [Pi.zero_apply, coe_zero, lintegral_const, zero_mul]
|
import Mathlib.Algebra.Group.Prod
import Mathlib.Algebra.Group.Units.Equiv
import Mathlib.Algebra.GroupPower.IterateHom
import Mathlib.Logic.Equiv.Set
import Mathlib.Tactic.Common
#align_import group_theory.perm.basic from "leanprover-community/mathlib"@"b86832321b586c6ac23ef8cdef6a7a27e42b13bd"
universe u v
namespace Equiv
variable {α : Type u} {β : Type v}
namespace Perm
instance instOne : One (Perm α) where one := Equiv.refl _
instance instMul : Mul (Perm α) where mul f g := Equiv.trans g f
instance instInv : Inv (Perm α) where inv := Equiv.symm
instance instPowNat : Pow (Perm α) ℕ where
pow f n := ⟨f^[n], f.symm^[n], f.left_inv.iterate _, f.right_inv.iterate _⟩
instance permGroup : Group (Perm α) where
mul_assoc f g h := (trans_assoc _ _ _).symm
one_mul := trans_refl
mul_one := refl_trans
mul_left_inv := self_trans_symm
npow n f := f ^ n
npow_succ n f := coe_fn_injective $ Function.iterate_succ _ _
zpow := zpowRec fun n f ↦ f ^ n
zpow_succ' n f := coe_fn_injective $ Function.iterate_succ _ _
#align equiv.perm.perm_group Equiv.Perm.permGroup
@[simp]
theorem default_eq : (default : Perm α) = 1 :=
rfl
#align equiv.perm.default_eq Equiv.Perm.default_eq
@[simps]
def equivUnitsEnd : Perm α ≃* Units (Function.End α) where
-- Porting note: needed to add `.toFun`.
toFun e := ⟨e.toFun, e.symm.toFun, e.self_comp_symm, e.symm_comp_self⟩
invFun u :=
⟨(u : Function.End α), (↑u⁻¹ : Function.End α), congr_fun u.inv_val, congr_fun u.val_inv⟩
left_inv _ := ext fun _ => rfl
right_inv _ := Units.ext rfl
map_mul' _ _ := rfl
#align equiv.perm.equiv_units_End Equiv.Perm.equivUnitsEnd
#align equiv.perm.equiv_units_End_symm_apply_apply Equiv.Perm.equivUnitsEnd_symm_apply_apply
#align equiv.perm.equiv_units_End_symm_apply_symm_apply Equiv.Perm.equivUnitsEnd_symm_apply_symm_apply
@[simps!]
def _root_.MonoidHom.toHomPerm {G : Type*} [Group G] (f : G →* Function.End α) : G →* Perm α :=
equivUnitsEnd.symm.toMonoidHom.comp f.toHomUnits
#align monoid_hom.to_hom_perm MonoidHom.toHomPerm
#align monoid_hom.to_hom_perm_apply_symm_apply MonoidHom.toHomPerm_apply_symm_apply
#align monoid_hom.to_hom_perm_apply_apply MonoidHom.toHomPerm_apply_apply
theorem mul_apply (f g : Perm α) (x) : (f * g) x = f (g x) :=
Equiv.trans_apply _ _ _
#align equiv.perm.mul_apply Equiv.Perm.mul_apply
theorem one_apply (x) : (1 : Perm α) x = x :=
rfl
#align equiv.perm.one_apply Equiv.Perm.one_apply
@[simp]
theorem inv_apply_self (f : Perm α) (x) : f⁻¹ (f x) = x :=
f.symm_apply_apply x
#align equiv.perm.inv_apply_self Equiv.Perm.inv_apply_self
@[simp]
theorem apply_inv_self (f : Perm α) (x) : f (f⁻¹ x) = x :=
f.apply_symm_apply x
#align equiv.perm.apply_inv_self Equiv.Perm.apply_inv_self
theorem one_def : (1 : Perm α) = Equiv.refl α :=
rfl
#align equiv.perm.one_def Equiv.Perm.one_def
theorem mul_def (f g : Perm α) : f * g = g.trans f :=
rfl
#align equiv.perm.mul_def Equiv.Perm.mul_def
theorem inv_def (f : Perm α) : f⁻¹ = f.symm :=
rfl
#align equiv.perm.inv_def Equiv.Perm.inv_def
@[simp, norm_cast] lemma coe_one : ⇑(1 : Perm α) = id := rfl
#align equiv.perm.coe_one Equiv.Perm.coe_one
@[simp, norm_cast] lemma coe_mul (f g : Perm α) : ⇑(f * g) = f ∘ g := rfl
#align equiv.perm.coe_mul Equiv.Perm.coe_mul
@[norm_cast] lemma coe_pow (f : Perm α) (n : ℕ) : ⇑(f ^ n) = f^[n] := rfl
#align equiv.perm.coe_pow Equiv.Perm.coe_pow
@[simp] lemma iterate_eq_pow (f : Perm α) (n : ℕ) : f^[n] = ⇑(f ^ n) := rfl
#align equiv.perm.iterate_eq_pow Equiv.Perm.iterate_eq_pow
theorem eq_inv_iff_eq {f : Perm α} {x y : α} : x = f⁻¹ y ↔ f x = y :=
f.eq_symm_apply
#align equiv.perm.eq_inv_iff_eq Equiv.Perm.eq_inv_iff_eq
theorem inv_eq_iff_eq {f : Perm α} {x y : α} : f⁻¹ x = y ↔ x = f y :=
f.symm_apply_eq
#align equiv.perm.inv_eq_iff_eq Equiv.Perm.inv_eq_iff_eq
theorem zpow_apply_comm {α : Type*} (σ : Perm α) (m n : ℤ) {x : α} :
(σ ^ m) ((σ ^ n) x) = (σ ^ n) ((σ ^ m) x) := by
rw [← Equiv.Perm.mul_apply, ← Equiv.Perm.mul_apply, zpow_mul_comm]
#align equiv.perm.zpow_apply_comm Equiv.Perm.zpow_apply_comm
@[simp] lemma image_inv (f : Perm α) (s : Set α) : ↑f⁻¹ '' s = f ⁻¹' s := f⁻¹.image_eq_preimage _
#align equiv.perm.image_inv Equiv.Perm.image_inv
@[simp] lemma preimage_inv (f : Perm α) (s : Set α) : ↑f⁻¹ ⁻¹' s = f '' s :=
(f.image_eq_preimage _).symm
#align equiv.perm.preimage_inv Equiv.Perm.preimage_inv
@[simp]
theorem trans_one {α : Sort*} {β : Type*} (e : α ≃ β) : e.trans (1 : Perm β) = e :=
Equiv.trans_refl e
#align equiv.perm.trans_one Equiv.Perm.trans_one
@[simp]
theorem mul_refl (e : Perm α) : e * Equiv.refl α = e :=
Equiv.trans_refl e
#align equiv.perm.mul_refl Equiv.Perm.mul_refl
@[simp]
theorem one_symm : (1 : Perm α).symm = 1 :=
Equiv.refl_symm
#align equiv.perm.one_symm Equiv.Perm.one_symm
@[simp]
theorem refl_inv : (Equiv.refl α : Perm α)⁻¹ = 1 :=
Equiv.refl_symm
#align equiv.perm.refl_inv Equiv.Perm.refl_inv
@[simp]
theorem one_trans {α : Type*} {β : Sort*} (e : α ≃ β) : (1 : Perm α).trans e = e :=
Equiv.refl_trans e
#align equiv.perm.one_trans Equiv.Perm.one_trans
@[simp]
theorem refl_mul (e : Perm α) : Equiv.refl α * e = e :=
Equiv.refl_trans e
#align equiv.perm.refl_mul Equiv.Perm.refl_mul
@[simp]
theorem inv_trans_self (e : Perm α) : e⁻¹.trans e = 1 :=
Equiv.symm_trans_self e
#align equiv.perm.inv_trans_self Equiv.Perm.inv_trans_self
@[simp]
theorem mul_symm (e : Perm α) : e * e.symm = 1 :=
Equiv.symm_trans_self e
#align equiv.perm.mul_symm Equiv.Perm.mul_symm
@[simp]
theorem self_trans_inv (e : Perm α) : e.trans e⁻¹ = 1 :=
Equiv.self_trans_symm e
#align equiv.perm.self_trans_inv Equiv.Perm.self_trans_inv
@[simp]
theorem symm_mul (e : Perm α) : e.symm * e = 1 :=
Equiv.self_trans_symm e
#align equiv.perm.symm_mul Equiv.Perm.symm_mul
@[simp]
theorem sumCongr_mul {α β : Type*} (e : Perm α) (f : Perm β) (g : Perm α) (h : Perm β) :
sumCongr e f * sumCongr g h = sumCongr (e * g) (f * h) :=
sumCongr_trans g h e f
#align equiv.perm.sum_congr_mul Equiv.Perm.sumCongr_mul
@[simp]
theorem sumCongr_inv {α β : Type*} (e : Perm α) (f : Perm β) :
(sumCongr e f)⁻¹ = sumCongr e⁻¹ f⁻¹ :=
sumCongr_symm e f
#align equiv.perm.sum_congr_inv Equiv.Perm.sumCongr_inv
@[simp]
theorem sumCongr_one {α β : Type*} : sumCongr (1 : Perm α) (1 : Perm β) = 1 :=
sumCongr_refl
#align equiv.perm.sum_congr_one Equiv.Perm.sumCongr_one
@[simps]
def sumCongrHom (α β : Type*) : Perm α × Perm β →* Perm (Sum α β) where
toFun a := sumCongr a.1 a.2
map_one' := sumCongr_one
map_mul' _ _ := (sumCongr_mul _ _ _ _).symm
#align equiv.perm.sum_congr_hom Equiv.Perm.sumCongrHom
#align equiv.perm.sum_congr_hom_apply Equiv.Perm.sumCongrHom_apply
theorem sumCongrHom_injective {α β : Type*} : Function.Injective (sumCongrHom α β) := by
rintro ⟨⟩ ⟨⟩ h
rw [Prod.mk.inj_iff]
constructor <;> ext i
· simpa using Equiv.congr_fun h (Sum.inl i)
· simpa using Equiv.congr_fun h (Sum.inr i)
#align equiv.perm.sum_congr_hom_injective Equiv.Perm.sumCongrHom_injective
@[simp]
theorem sumCongr_swap_one {α β : Type*} [DecidableEq α] [DecidableEq β] (i j : α) :
sumCongr (Equiv.swap i j) (1 : Perm β) = Equiv.swap (Sum.inl i) (Sum.inl j) :=
sumCongr_swap_refl i j
#align equiv.perm.sum_congr_swap_one Equiv.Perm.sumCongr_swap_one
@[simp]
theorem sumCongr_one_swap {α β : Type*} [DecidableEq α] [DecidableEq β] (i j : β) :
sumCongr (1 : Perm α) (Equiv.swap i j) = Equiv.swap (Sum.inr i) (Sum.inr j) :=
sumCongr_refl_swap i j
#align equiv.perm.sum_congr_one_swap Equiv.Perm.sumCongr_one_swap
@[simp]
theorem sigmaCongrRight_mul {α : Type*} {β : α → Type*} (F : ∀ a, Perm (β a))
(G : ∀ a, Perm (β a)) : sigmaCongrRight F * sigmaCongrRight G = sigmaCongrRight (F * G) :=
sigmaCongrRight_trans G F
#align equiv.perm.sigma_congr_right_mul Equiv.Perm.sigmaCongrRight_mul
@[simp]
theorem sigmaCongrRight_inv {α : Type*} {β : α → Type*} (F : ∀ a, Perm (β a)) :
(sigmaCongrRight F)⁻¹ = sigmaCongrRight fun a => (F a)⁻¹ :=
sigmaCongrRight_symm F
#align equiv.perm.sigma_congr_right_inv Equiv.Perm.sigmaCongrRight_inv
@[simp]
theorem sigmaCongrRight_one {α : Type*} {β : α → Type*} :
sigmaCongrRight (1 : ∀ a, Equiv.Perm <| β a) = 1 :=
sigmaCongrRight_refl
#align equiv.perm.sigma_congr_right_one Equiv.Perm.sigmaCongrRight_one
@[simps]
def sigmaCongrRightHom {α : Type*} (β : α → Type*) : (∀ a, Perm (β a)) →* Perm (Σa, β a) where
toFun := sigmaCongrRight
map_one' := sigmaCongrRight_one
map_mul' _ _ := (sigmaCongrRight_mul _ _).symm
#align equiv.perm.sigma_congr_right_hom Equiv.Perm.sigmaCongrRightHom
#align equiv.perm.sigma_congr_right_hom_apply Equiv.Perm.sigmaCongrRightHom_apply
theorem sigmaCongrRightHom_injective {α : Type*} {β : α → Type*} :
Function.Injective (sigmaCongrRightHom β) := by
intro x y h
ext a b
simpa using Equiv.congr_fun h ⟨a, b⟩
#align equiv.perm.sigma_congr_right_hom_injective Equiv.Perm.sigmaCongrRightHom_injective
@[simps]
def subtypeCongrHom (p : α → Prop) [DecidablePred p] :
Perm { a // p a } × Perm { a // ¬p a } →* Perm α where
toFun pair := Perm.subtypeCongr pair.fst pair.snd
map_one' := Perm.subtypeCongr.refl
map_mul' _ _ := (Perm.subtypeCongr.trans _ _ _ _).symm
#align equiv.perm.subtype_congr_hom Equiv.Perm.subtypeCongrHom
#align equiv.perm.subtype_congr_hom_apply Equiv.Perm.subtypeCongrHom_apply
theorem subtypeCongrHom_injective (p : α → Prop) [DecidablePred p] :
Function.Injective (subtypeCongrHom p) := by
rintro ⟨⟩ ⟨⟩ h
rw [Prod.mk.inj_iff]
constructor <;> ext i <;> simpa using Equiv.congr_fun h i
#align equiv.perm.subtype_congr_hom_injective Equiv.Perm.subtypeCongrHom_injective
@[simp]
theorem permCongr_eq_mul (e p : Perm α) : e.permCongr p = e * p * e⁻¹ :=
rfl
#align equiv.perm.perm_congr_eq_mul Equiv.Perm.permCongr_eq_mul
section Swap
variable [DecidableEq α]
@[simp]
theorem swap_inv (x y : α) : (swap x y)⁻¹ = swap x y :=
rfl
#align equiv.swap_inv Equiv.swap_inv
@[simp]
theorem swap_mul_self (i j : α) : swap i j * swap i j = 1 :=
swap_swap i j
#align equiv.swap_mul_self Equiv.swap_mul_self
theorem swap_mul_eq_mul_swap (f : Perm α) (x y : α) : swap x y * f = f * swap (f⁻¹ x) (f⁻¹ y) :=
Equiv.ext fun z => by
simp only [Perm.mul_apply, swap_apply_def]
split_ifs <;>
simp_all only [Perm.apply_inv_self, Perm.eq_inv_iff_eq, eq_self_iff_true, not_true]
#align equiv.swap_mul_eq_mul_swap Equiv.swap_mul_eq_mul_swap
theorem mul_swap_eq_swap_mul (f : Perm α) (x y : α) : f * swap x y = swap (f x) (f y) * f := by
rw [swap_mul_eq_mul_swap, Perm.inv_apply_self, Perm.inv_apply_self]
#align equiv.mul_swap_eq_swap_mul Equiv.mul_swap_eq_swap_mul
theorem swap_apply_apply (f : Perm α) (x y : α) : swap (f x) (f y) = f * swap x y * f⁻¹ := by
rw [mul_swap_eq_swap_mul, mul_inv_cancel_right]
#align equiv.swap_apply_apply Equiv.swap_apply_apply
@[simp]
| Mathlib/GroupTheory/Perm/Basic.lean | 546 | 547 | theorem swap_smul_self_smul [MulAction (Perm α) β] (i j : α) (x : β) :
swap i j • swap i j • x = x := by | simp [smul_smul]
|
import Mathlib.Data.Finset.Image
import Mathlib.Data.List.FinRange
#align_import data.fintype.basic from "leanprover-community/mathlib"@"d78597269638367c3863d40d45108f52207e03cf"
assert_not_exists MonoidWithZero
assert_not_exists MulAction
open Function
open Nat
universe u v
variable {α β γ : Type*}
class Fintype (α : Type*) where
elems : Finset α
complete : ∀ x : α, x ∈ elems
#align fintype Fintype
namespace Finset
variable [Fintype α] {s t : Finset α}
def univ : Finset α :=
@Fintype.elems α _
#align finset.univ Finset.univ
@[simp]
theorem mem_univ (x : α) : x ∈ (univ : Finset α) :=
Fintype.complete x
#align finset.mem_univ Finset.mem_univ
-- Porting note: removing @[simp], simp can prove it
theorem mem_univ_val : ∀ x, x ∈ (univ : Finset α).1 :=
mem_univ
#align finset.mem_univ_val Finset.mem_univ_val
theorem eq_univ_iff_forall : s = univ ↔ ∀ x, x ∈ s := by simp [ext_iff]
#align finset.eq_univ_iff_forall Finset.eq_univ_iff_forall
theorem eq_univ_of_forall : (∀ x, x ∈ s) → s = univ :=
eq_univ_iff_forall.2
#align finset.eq_univ_of_forall Finset.eq_univ_of_forall
@[simp, norm_cast]
theorem coe_univ : ↑(univ : Finset α) = (Set.univ : Set α) := by ext; simp
#align finset.coe_univ Finset.coe_univ
@[simp, norm_cast]
theorem coe_eq_univ : (s : Set α) = Set.univ ↔ s = univ := by rw [← coe_univ, coe_inj]
#align finset.coe_eq_univ Finset.coe_eq_univ
theorem Nonempty.eq_univ [Subsingleton α] : s.Nonempty → s = univ := by
rintro ⟨x, hx⟩
exact eq_univ_of_forall fun y => by rwa [Subsingleton.elim y x]
#align finset.nonempty.eq_univ Finset.Nonempty.eq_univ
theorem univ_nonempty_iff : (univ : Finset α).Nonempty ↔ Nonempty α := by
rw [← coe_nonempty, coe_univ, Set.nonempty_iff_univ_nonempty]
#align finset.univ_nonempty_iff Finset.univ_nonempty_iff
@[aesop unsafe apply (rule_sets := [finsetNonempty])]
theorem univ_nonempty [Nonempty α] : (univ : Finset α).Nonempty :=
univ_nonempty_iff.2 ‹_›
#align finset.univ_nonempty Finset.univ_nonempty
theorem univ_eq_empty_iff : (univ : Finset α) = ∅ ↔ IsEmpty α := by
rw [← not_nonempty_iff, ← univ_nonempty_iff, not_nonempty_iff_eq_empty]
#align finset.univ_eq_empty_iff Finset.univ_eq_empty_iff
@[simp]
theorem univ_eq_empty [IsEmpty α] : (univ : Finset α) = ∅ :=
univ_eq_empty_iff.2 ‹_›
#align finset.univ_eq_empty Finset.univ_eq_empty
@[simp]
theorem univ_unique [Unique α] : (univ : Finset α) = {default} :=
Finset.ext fun x => iff_of_true (mem_univ _) <| mem_singleton.2 <| Subsingleton.elim x default
#align finset.univ_unique Finset.univ_unique
@[simp]
theorem subset_univ (s : Finset α) : s ⊆ univ := fun a _ => mem_univ a
#align finset.subset_univ Finset.subset_univ
instance boundedOrder : BoundedOrder (Finset α) :=
{ inferInstanceAs (OrderBot (Finset α)) with
top := univ
le_top := subset_univ }
#align finset.bounded_order Finset.boundedOrder
@[simp]
theorem top_eq_univ : (⊤ : Finset α) = univ :=
rfl
#align finset.top_eq_univ Finset.top_eq_univ
theorem ssubset_univ_iff {s : Finset α} : s ⊂ univ ↔ s ≠ univ :=
@lt_top_iff_ne_top _ _ _ s
#align finset.ssubset_univ_iff Finset.ssubset_univ_iff
@[simp]
theorem univ_subset_iff {s : Finset α} : univ ⊆ s ↔ s = univ :=
@top_le_iff _ _ _ s
theorem codisjoint_left : Codisjoint s t ↔ ∀ ⦃a⦄, a ∉ s → a ∈ t := by
classical simp [codisjoint_iff, eq_univ_iff_forall, or_iff_not_imp_left]
#align finset.codisjoint_left Finset.codisjoint_left
theorem codisjoint_right : Codisjoint s t ↔ ∀ ⦃a⦄, a ∉ t → a ∈ s :=
Codisjoint_comm.trans codisjoint_left
#align finset.codisjoint_right Finset.codisjoint_right
open Finset Function
namespace Fintype
instance decidablePiFintype {α} {β : α → Type*} [∀ a, DecidableEq (β a)] [Fintype α] :
DecidableEq (∀ a, β a) := fun f g =>
decidable_of_iff (∀ a ∈ @Fintype.elems α _, f a = g a)
(by simp [Function.funext_iff, Fintype.complete])
#align fintype.decidable_pi_fintype Fintype.decidablePiFintype
instance decidableForallFintype {p : α → Prop} [DecidablePred p] [Fintype α] :
Decidable (∀ a, p a) :=
decidable_of_iff (∀ a ∈ @univ α _, p a) (by simp)
#align fintype.decidable_forall_fintype Fintype.decidableForallFintype
instance decidableExistsFintype {p : α → Prop} [DecidablePred p] [Fintype α] :
Decidable (∃ a, p a) :=
decidable_of_iff (∃ a ∈ @univ α _, p a) (by simp)
#align fintype.decidable_exists_fintype Fintype.decidableExistsFintype
instance decidableMemRangeFintype [Fintype α] [DecidableEq β] (f : α → β) :
DecidablePred (· ∈ Set.range f) := fun _ => Fintype.decidableExistsFintype
#align fintype.decidable_mem_range_fintype Fintype.decidableMemRangeFintype
instance decidableSubsingleton [Fintype α] [DecidableEq α] {s : Set α} [DecidablePred (· ∈ s)] :
Decidable s.Subsingleton := decidable_of_iff (∀ a ∈ s, ∀ b ∈ s, a = b) Iff.rfl
section Inv
namespace Function
variable [Fintype α] [DecidableEq β]
namespace Set
variable {s t : Set α}
def toFinset (s : Set α) [Fintype s] : Finset α :=
(@Finset.univ s _).map <| Function.Embedding.subtype _
#align set.to_finset Set.toFinset
@[congr]
theorem toFinset_congr {s t : Set α} [Fintype s] [Fintype t] (h : s = t) :
toFinset s = toFinset t := by subst h; congr; exact Subsingleton.elim _ _
#align set.to_finset_congr Set.toFinset_congr
@[simp]
theorem mem_toFinset {s : Set α} [Fintype s] {a : α} : a ∈ s.toFinset ↔ a ∈ s := by
simp [toFinset]
#align set.mem_to_finset Set.mem_toFinset
theorem toFinset_ofFinset {p : Set α} (s : Finset α) (H : ∀ x, x ∈ s ↔ x ∈ p) :
@Set.toFinset _ p (Fintype.ofFinset s H) = s :=
Finset.ext fun x => by rw [@mem_toFinset _ _ (id _), H]
#align set.to_finset_of_finset Set.toFinset_ofFinset
def decidableMemOfFintype [DecidableEq α] (s : Set α) [Fintype s] (a) : Decidable (a ∈ s) :=
decidable_of_iff _ mem_toFinset
#align set.decidable_mem_of_fintype Set.decidableMemOfFintype
@[simp]
theorem coe_toFinset (s : Set α) [Fintype s] : (↑s.toFinset : Set α) = s :=
Set.ext fun _ => mem_toFinset
#align set.coe_to_finset Set.coe_toFinset
@[simp, aesop safe apply (rule_sets := [finsetNonempty])]
theorem toFinset_nonempty {s : Set α} [Fintype s] : s.toFinset.Nonempty ↔ s.Nonempty := by
rw [← Finset.coe_nonempty, coe_toFinset]
#align set.to_finset_nonempty Set.toFinset_nonempty
@[simp]
theorem toFinset_inj {s t : Set α} [Fintype s] [Fintype t] : s.toFinset = t.toFinset ↔ s = t :=
⟨fun h => by rw [← s.coe_toFinset, h, t.coe_toFinset], fun h => by simp [h]⟩
#align set.to_finset_inj Set.toFinset_inj
@[mono]
theorem toFinset_subset_toFinset [Fintype s] [Fintype t] : s.toFinset ⊆ t.toFinset ↔ s ⊆ t := by
simp [Finset.subset_iff, Set.subset_def]
#align set.to_finset_subset_to_finset Set.toFinset_subset_toFinset
@[simp]
theorem toFinset_ssubset [Fintype s] {t : Finset α} : s.toFinset ⊂ t ↔ s ⊂ t := by
rw [← Finset.coe_ssubset, coe_toFinset]
#align set.to_finset_ssubset Set.toFinset_ssubset
@[simp]
theorem subset_toFinset {s : Finset α} [Fintype t] : s ⊆ t.toFinset ↔ ↑s ⊆ t := by
rw [← Finset.coe_subset, coe_toFinset]
#align set.subset_to_finset Set.subset_toFinset
@[simp]
theorem ssubset_toFinset {s : Finset α} [Fintype t] : s ⊂ t.toFinset ↔ ↑s ⊂ t := by
rw [← Finset.coe_ssubset, coe_toFinset]
#align set.ssubset_to_finset Set.ssubset_toFinset
@[mono]
| Mathlib/Data/Fintype/Basic.lean | 661 | 662 | theorem toFinset_ssubset_toFinset [Fintype s] [Fintype t] : s.toFinset ⊂ t.toFinset ↔ s ⊂ t := by |
simp only [Finset.ssubset_def, toFinset_subset_toFinset, ssubset_def]
|
import Mathlib.Logic.Nonempty
import Mathlib.Init.Set
import Mathlib.Logic.Basic
#align_import logic.function.basic from "leanprover-community/mathlib"@"29cb56a7b35f72758b05a30490e1f10bd62c35c1"
open Function
universe u v w
namespace Function
section
variable {α β γ : Sort*} {f : α → β}
@[reducible, simp] def eval {β : α → Sort*} (x : α) (f : ∀ x, β x) : β x := f x
#align function.eval Function.eval
theorem eval_apply {β : α → Sort*} (x : α) (f : ∀ x, β x) : eval x f = f x :=
rfl
#align function.eval_apply Function.eval_apply
theorem const_def {y : β} : (fun _ : α ↦ y) = const α y :=
rfl
#align function.const_def Function.const_def
theorem const_injective [Nonempty α] : Injective (const α : β → α → β) := fun y₁ y₂ h ↦
let ⟨x⟩ := ‹Nonempty α›
congr_fun h x
#align function.const_injective Function.const_injective
@[simp]
theorem const_inj [Nonempty α] {y₁ y₂ : β} : const α y₁ = const α y₂ ↔ y₁ = y₂ :=
⟨fun h ↦ const_injective h, fun h ↦ h ▸ rfl⟩
#align function.const_inj Function.const_inj
#align function.id_def Function.id_def
-- Porting note: `Function.onFun` is now reducible
-- @[simp]
theorem onFun_apply (f : β → β → γ) (g : α → β) (a b : α) : onFun f g a b = f (g a) (g b) :=
rfl
#align function.on_fun_apply Function.onFun_apply
lemma hfunext {α α' : Sort u} {β : α → Sort v} {β' : α' → Sort v} {f : ∀a, β a} {f' : ∀a, β' a}
(hα : α = α') (h : ∀a a', HEq a a' → HEq (f a) (f' a')) : HEq f f' := by
subst hα
have : ∀a, HEq (f a) (f' a) := fun a ↦ h a a (HEq.refl a)
have : β = β' := by funext a; exact type_eq_of_heq (this a)
subst this
apply heq_of_eq
funext a
exact eq_of_heq (this a)
#align function.hfunext Function.hfunext
#align function.funext_iff Function.funext_iff
theorem ne_iff {β : α → Sort*} {f₁ f₂ : ∀ a, β a} : f₁ ≠ f₂ ↔ ∃ a, f₁ a ≠ f₂ a :=
funext_iff.not.trans not_forall
#align function.ne_iff Function.ne_iff
lemma funext_iff_of_subsingleton [Subsingleton α] {g : α → β} (x y : α) :
f x = g y ↔ f = g := by
refine ⟨fun h ↦ funext fun z ↦ ?_, fun h ↦ ?_⟩
· rwa [Subsingleton.elim x z, Subsingleton.elim y z] at h
· rw [h, Subsingleton.elim x y]
protected theorem Bijective.injective {f : α → β} (hf : Bijective f) : Injective f := hf.1
#align function.bijective.injective Function.Bijective.injective
protected theorem Bijective.surjective {f : α → β} (hf : Bijective f) : Surjective f := hf.2
#align function.bijective.surjective Function.Bijective.surjective
theorem Injective.eq_iff (I : Injective f) {a b : α} : f a = f b ↔ a = b :=
⟨@I _ _, congr_arg f⟩
#align function.injective.eq_iff Function.Injective.eq_iff
theorem Injective.beq_eq {α β : Type*} [BEq α] [LawfulBEq α] [BEq β] [LawfulBEq β] {f : α → β}
(I : Injective f) {a b : α} : (f a == f b) = (a == b) := by
by_cases h : a == b <;> simp [h] <;> simpa [I.eq_iff] using h
theorem Injective.eq_iff' (I : Injective f) {a b : α} {c : β} (h : f b = c) : f a = c ↔ a = b :=
h ▸ I.eq_iff
#align function.injective.eq_iff' Function.Injective.eq_iff'
theorem Injective.ne (hf : Injective f) {a₁ a₂ : α} : a₁ ≠ a₂ → f a₁ ≠ f a₂ :=
mt fun h ↦ hf h
#align function.injective.ne Function.Injective.ne
theorem Injective.ne_iff (hf : Injective f) {x y : α} : f x ≠ f y ↔ x ≠ y :=
⟨mt <| congr_arg f, hf.ne⟩
#align function.injective.ne_iff Function.Injective.ne_iff
theorem Injective.ne_iff' (hf : Injective f) {x y : α} {z : β} (h : f y = z) : f x ≠ z ↔ x ≠ y :=
h ▸ hf.ne_iff
#align function.injective.ne_iff' Function.Injective.ne_iff'
theorem not_injective_iff : ¬ Injective f ↔ ∃ a b, f a = f b ∧ a ≠ b := by
simp only [Injective, not_forall, exists_prop]
protected def Injective.decidableEq [DecidableEq β] (I : Injective f) : DecidableEq α :=
fun _ _ ↦ decidable_of_iff _ I.eq_iff
#align function.injective.decidable_eq Function.Injective.decidableEq
theorem Injective.of_comp {g : γ → α} (I : Injective (f ∘ g)) : Injective g :=
fun _ _ h ↦ I <| congr_arg f h
#align function.injective.of_comp Function.Injective.of_comp
@[simp]
theorem Injective.of_comp_iff (hf : Injective f) (g : γ → α) :
Injective (f ∘ g) ↔ Injective g :=
⟨Injective.of_comp, hf.comp⟩
#align function.injective.of_comp_iff Function.Injective.of_comp_iff
theorem Injective.of_comp_right {g : γ → α} (I : Injective (f ∘ g)) (hg : Surjective g) :
Injective f := fun x y h ↦ by
obtain ⟨x, rfl⟩ := hg x
obtain ⟨y, rfl⟩ := hg y
exact congr_arg g (I h)
theorem Surjective.bijective₂_of_injective {g : γ → α} (hf : Surjective f) (hg : Surjective g)
(I : Injective (f ∘ g)) : Bijective f ∧ Bijective g :=
⟨⟨I.of_comp_right hg, hf⟩, I.of_comp, hg⟩
@[simp]
theorem Injective.of_comp_iff' (f : α → β) {g : γ → α} (hg : Bijective g) :
Injective (f ∘ g) ↔ Injective f :=
⟨fun I ↦ I.of_comp_right hg.2, fun h ↦ h.comp hg.injective⟩
#align function.injective.of_comp_iff' Function.Injective.of_comp_iff'
theorem Injective.comp_left {g : β → γ} (hg : Function.Injective g) :
Function.Injective (g ∘ · : (α → β) → α → γ) :=
fun _ _ hgf ↦ funext fun i ↦ hg <| (congr_fun hgf i : _)
#align function.injective.comp_left Function.Injective.comp_left
theorem injective_of_subsingleton [Subsingleton α] (f : α → β) : Injective f :=
fun _ _ _ ↦ Subsingleton.elim _ _
#align function.injective_of_subsingleton Function.injective_of_subsingleton
lemma Injective.dite (p : α → Prop) [DecidablePred p]
{f : {a : α // p a} → β} {f' : {a : α // ¬ p a} → β}
(hf : Injective f) (hf' : Injective f')
(im_disj : ∀ {x x' : α} {hx : p x} {hx' : ¬ p x'}, f ⟨x, hx⟩ ≠ f' ⟨x', hx'⟩) :
Function.Injective (fun x ↦ if h : p x then f ⟨x, h⟩ else f' ⟨x, h⟩) := fun x₁ x₂ h => by
dsimp only at h
by_cases h₁ : p x₁ <;> by_cases h₂ : p x₂
· rw [dif_pos h₁, dif_pos h₂] at h; injection (hf h)
· rw [dif_pos h₁, dif_neg h₂] at h; exact (im_disj h).elim
· rw [dif_neg h₁, dif_pos h₂] at h; exact (im_disj h.symm).elim
· rw [dif_neg h₁, dif_neg h₂] at h; injection (hf' h)
#align function.injective.dite Function.Injective.dite
theorem Surjective.of_comp {g : γ → α} (S : Surjective (f ∘ g)) : Surjective f := fun y ↦
let ⟨x, h⟩ := S y
⟨g x, h⟩
#align function.surjective.of_comp Function.Surjective.of_comp
@[simp]
theorem Surjective.of_comp_iff (f : α → β) {g : γ → α} (hg : Surjective g) :
Surjective (f ∘ g) ↔ Surjective f :=
⟨Surjective.of_comp, fun h ↦ h.comp hg⟩
#align function.surjective.of_comp_iff Function.Surjective.of_comp_iff
theorem Surjective.of_comp_left {g : γ → α} (S : Surjective (f ∘ g)) (hf : Injective f) :
Surjective g := fun a ↦ let ⟨c, hc⟩ := S (f a); ⟨c, hf hc⟩
theorem Injective.bijective₂_of_surjective {g : γ → α} (hf : Injective f) (hg : Injective g)
(S : Surjective (f ∘ g)) : Bijective f ∧ Bijective g :=
⟨⟨hf, S.of_comp⟩, hg, S.of_comp_left hf⟩
@[simp]
theorem Surjective.of_comp_iff' (hf : Bijective f) (g : γ → α) :
Surjective (f ∘ g) ↔ Surjective g :=
⟨fun S ↦ S.of_comp_left hf.1, hf.surjective.comp⟩
#align function.surjective.of_comp_iff' Function.Surjective.of_comp_iff'
instance decidableEqPFun (p : Prop) [Decidable p] (α : p → Type*) [∀ hp, DecidableEq (α hp)] :
DecidableEq (∀ hp, α hp)
| f, g => decidable_of_iff (∀ hp, f hp = g hp) funext_iff.symm
protected theorem Surjective.forall (hf : Surjective f) {p : β → Prop} :
(∀ y, p y) ↔ ∀ x, p (f x) :=
⟨fun h x ↦ h (f x), fun h y ↦
let ⟨x, hx⟩ := hf y
hx ▸ h x⟩
#align function.surjective.forall Function.Surjective.forall
protected theorem Surjective.forall₂ (hf : Surjective f) {p : β → β → Prop} :
(∀ y₁ y₂, p y₁ y₂) ↔ ∀ x₁ x₂, p (f x₁) (f x₂) :=
hf.forall.trans <| forall_congr' fun _ ↦ hf.forall
#align function.surjective.forall₂ Function.Surjective.forall₂
protected theorem Surjective.forall₃ (hf : Surjective f) {p : β → β → β → Prop} :
(∀ y₁ y₂ y₃, p y₁ y₂ y₃) ↔ ∀ x₁ x₂ x₃, p (f x₁) (f x₂) (f x₃) :=
hf.forall.trans <| forall_congr' fun _ ↦ hf.forall₂
#align function.surjective.forall₃ Function.Surjective.forall₃
protected theorem Surjective.exists (hf : Surjective f) {p : β → Prop} :
(∃ y, p y) ↔ ∃ x, p (f x) :=
⟨fun ⟨y, hy⟩ ↦
let ⟨x, hx⟩ := hf y
⟨x, hx.symm ▸ hy⟩,
fun ⟨x, hx⟩ ↦ ⟨f x, hx⟩⟩
#align function.surjective.exists Function.Surjective.exists
protected theorem Surjective.exists₂ (hf : Surjective f) {p : β → β → Prop} :
(∃ y₁ y₂, p y₁ y₂) ↔ ∃ x₁ x₂, p (f x₁) (f x₂) :=
hf.exists.trans <| exists_congr fun _ ↦ hf.exists
#align function.surjective.exists₂ Function.Surjective.exists₂
protected theorem Surjective.exists₃ (hf : Surjective f) {p : β → β → β → Prop} :
(∃ y₁ y₂ y₃, p y₁ y₂ y₃) ↔ ∃ x₁ x₂ x₃, p (f x₁) (f x₂) (f x₃) :=
hf.exists.trans <| exists_congr fun _ ↦ hf.exists₂
#align function.surjective.exists₃ Function.Surjective.exists₃
theorem Surjective.injective_comp_right (hf : Surjective f) : Injective fun g : β → γ ↦ g ∘ f :=
fun _ _ h ↦ funext <| hf.forall.2 <| congr_fun h
#align function.surjective.injective_comp_right Function.Surjective.injective_comp_right
protected theorem Surjective.right_cancellable (hf : Surjective f) {g₁ g₂ : β → γ} :
g₁ ∘ f = g₂ ∘ f ↔ g₁ = g₂ :=
hf.injective_comp_right.eq_iff
#align function.surjective.right_cancellable Function.Surjective.right_cancellable
theorem surjective_of_right_cancellable_Prop (h : ∀ g₁ g₂ : β → Prop, g₁ ∘ f = g₂ ∘ f → g₁ = g₂) :
Surjective f := by
specialize h (fun y ↦ ∃ x, f x = y) (fun _ ↦ True) (funext fun x ↦ eq_true ⟨_, rfl⟩)
intro y; rw [congr_fun h y]; trivial
#align function.surjective_of_right_cancellable_Prop Function.surjective_of_right_cancellable_Prop
theorem bijective_iff_existsUnique (f : α → β) : Bijective f ↔ ∀ b : β, ∃! a : α, f a = b :=
⟨fun hf b ↦
let ⟨a, ha⟩ := hf.surjective b
⟨a, ha, fun _ ha' ↦ hf.injective (ha'.trans ha.symm)⟩,
fun he ↦ ⟨fun {_a a'} h ↦ (he (f a')).unique h rfl, fun b ↦ (he b).exists⟩⟩
#align function.bijective_iff_exists_unique Function.bijective_iff_existsUnique
protected theorem Bijective.existsUnique {f : α → β} (hf : Bijective f) (b : β) :
∃! a : α, f a = b :=
(bijective_iff_existsUnique f).mp hf b
#align function.bijective.exists_unique Function.Bijective.existsUnique
theorem Bijective.existsUnique_iff {f : α → β} (hf : Bijective f) {p : β → Prop} :
(∃! y, p y) ↔ ∃! x, p (f x) :=
⟨fun ⟨y, hpy, hy⟩ ↦
let ⟨x, hx⟩ := hf.surjective y
⟨x, by simpa [hx], fun z (hz : p (f z)) ↦ hf.injective <| hx.symm ▸ hy _ hz⟩,
fun ⟨x, hpx, hx⟩ ↦
⟨f x, hpx, fun y hy ↦
let ⟨z, hz⟩ := hf.surjective y
hz ▸ congr_arg f (hx _ (by simpa [hz]))⟩⟩
#align function.bijective.exists_unique_iff Function.Bijective.existsUnique_iff
theorem Bijective.of_comp_iff (f : α → β) {g : γ → α} (hg : Bijective g) :
Bijective (f ∘ g) ↔ Bijective f :=
and_congr (Injective.of_comp_iff' _ hg) (Surjective.of_comp_iff _ hg.surjective)
#align function.bijective.of_comp_iff Function.Bijective.of_comp_iff
theorem Bijective.of_comp_iff' {f : α → β} (hf : Bijective f) (g : γ → α) :
Function.Bijective (f ∘ g) ↔ Function.Bijective g :=
and_congr (Injective.of_comp_iff hf.injective _) (Surjective.of_comp_iff' hf _)
#align function.bijective.of_comp_iff' Function.Bijective.of_comp_iff'
theorem cantor_surjective {α} (f : α → Set α) : ¬Surjective f
| h => let ⟨D, e⟩ := h {a | ¬ f a a}
@iff_not_self (D ∈ f D) <| iff_of_eq <| congr_arg (D ∈ ·) e
#align function.cantor_surjective Function.cantor_surjective
theorem cantor_injective {α : Type*} (f : Set α → α) : ¬Injective f
| i => cantor_surjective (fun a ↦ {b | ∀ U, a = f U → U b}) <|
RightInverse.surjective (fun U ↦ Set.ext fun _ ↦ ⟨fun h ↦ h U rfl, fun h _ e ↦ i e ▸ h⟩)
#align function.cantor_injective Function.cantor_injective
theorem not_surjective_Type {α : Type u} (f : α → Type max u v) : ¬Surjective f := by
intro hf
let T : Type max u v := Sigma f
cases hf (Set T) with | intro U hU =>
let g : Set T → T := fun s ↦ ⟨U, cast hU.symm s⟩
have hg : Injective g := by
intro s t h
suffices cast hU (g s).2 = cast hU (g t).2 by
simp only [cast_cast, cast_eq] at this
assumption
· congr
exact cantor_injective g hg
#align function.not_surjective_Type Function.not_surjective_Type
def IsPartialInv {α β} (f : α → β) (g : β → Option α) : Prop :=
∀ x y, g y = some x ↔ f x = y
#align function.is_partial_inv Function.IsPartialInv
theorem isPartialInv_left {α β} {f : α → β} {g} (H : IsPartialInv f g) (x) : g (f x) = some x :=
(H _ _).2 rfl
#align function.is_partial_inv_left Function.isPartialInv_left
theorem injective_of_isPartialInv {α β} {f : α → β} {g} (H : IsPartialInv f g) :
Injective f := fun _ _ h ↦
Option.some.inj <| ((H _ _).2 h).symm.trans ((H _ _).2 rfl)
#align function.injective_of_partial_inv Function.injective_of_isPartialInv
theorem injective_of_isPartialInv_right {α β} {f : α → β} {g} (H : IsPartialInv f g) (x y b)
(h₁ : b ∈ g x) (h₂ : b ∈ g y) : x = y :=
((H _ _).1 h₁).symm.trans ((H _ _).1 h₂)
#align function.injective_of_partial_inv_right Function.injective_of_isPartialInv_right
theorem LeftInverse.comp_eq_id {f : α → β} {g : β → α} (h : LeftInverse f g) : f ∘ g = id :=
funext h
#align function.left_inverse.comp_eq_id Function.LeftInverse.comp_eq_id
theorem leftInverse_iff_comp {f : α → β} {g : β → α} : LeftInverse f g ↔ f ∘ g = id :=
⟨LeftInverse.comp_eq_id, congr_fun⟩
#align function.left_inverse_iff_comp Function.leftInverse_iff_comp
theorem RightInverse.comp_eq_id {f : α → β} {g : β → α} (h : RightInverse f g) : g ∘ f = id :=
funext h
#align function.right_inverse.comp_eq_id Function.RightInverse.comp_eq_id
theorem rightInverse_iff_comp {f : α → β} {g : β → α} : RightInverse f g ↔ g ∘ f = id :=
⟨RightInverse.comp_eq_id, congr_fun⟩
#align function.right_inverse_iff_comp Function.rightInverse_iff_comp
theorem LeftInverse.comp {f : α → β} {g : β → α} {h : β → γ} {i : γ → β} (hf : LeftInverse f g)
(hh : LeftInverse h i) : LeftInverse (h ∘ f) (g ∘ i) :=
fun a ↦ show h (f (g (i a))) = a by rw [hf (i a), hh a]
#align function.left_inverse.comp Function.LeftInverse.comp
theorem RightInverse.comp {f : α → β} {g : β → α} {h : β → γ} {i : γ → β} (hf : RightInverse f g)
(hh : RightInverse h i) : RightInverse (h ∘ f) (g ∘ i) :=
LeftInverse.comp hh hf
#align function.right_inverse.comp Function.RightInverse.comp
theorem LeftInverse.rightInverse {f : α → β} {g : β → α} (h : LeftInverse g f) : RightInverse f g :=
h
#align function.left_inverse.right_inverse Function.LeftInverse.rightInverse
theorem RightInverse.leftInverse {f : α → β} {g : β → α} (h : RightInverse g f) : LeftInverse f g :=
h
#align function.right_inverse.left_inverse Function.RightInverse.leftInverse
theorem LeftInverse.surjective {f : α → β} {g : β → α} (h : LeftInverse f g) : Surjective f :=
h.rightInverse.surjective
#align function.left_inverse.surjective Function.LeftInverse.surjective
theorem RightInverse.injective {f : α → β} {g : β → α} (h : RightInverse f g) : Injective f :=
h.leftInverse.injective
#align function.right_inverse.injective Function.RightInverse.injective
theorem LeftInverse.rightInverse_of_injective {f : α → β} {g : β → α} (h : LeftInverse f g)
(hf : Injective f) : RightInverse f g :=
fun x ↦ hf <| h (f x)
#align function.left_inverse.right_inverse_of_injective Function.LeftInverse.rightInverse_of_injective
theorem LeftInverse.rightInverse_of_surjective {f : α → β} {g : β → α} (h : LeftInverse f g)
(hg : Surjective g) : RightInverse f g :=
fun x ↦ let ⟨y, hy⟩ := hg x; hy ▸ congr_arg g (h y)
#align function.left_inverse.right_inverse_of_surjective Function.LeftInverse.rightInverse_of_surjective
theorem RightInverse.leftInverse_of_surjective {f : α → β} {g : β → α} :
RightInverse f g → Surjective f → LeftInverse f g :=
LeftInverse.rightInverse_of_surjective
#align function.right_inverse.left_inverse_of_surjective Function.RightInverse.leftInverse_of_surjective
theorem RightInverse.leftInverse_of_injective {f : α → β} {g : β → α} :
RightInverse f g → Injective g → LeftInverse f g :=
LeftInverse.rightInverse_of_injective
#align function.right_inverse.left_inverse_of_injective Function.RightInverse.leftInverse_of_injective
theorem LeftInverse.eq_rightInverse {f : α → β} {g₁ g₂ : β → α} (h₁ : LeftInverse g₁ f)
(h₂ : RightInverse g₂ f) : g₁ = g₂ :=
calc
g₁ = g₁ ∘ f ∘ g₂ := by rw [h₂.comp_eq_id, comp_id]
_ = g₂ := by rw [← comp.assoc, h₁.comp_eq_id, id_comp]
#align function.left_inverse.eq_right_inverse Function.LeftInverse.eq_rightInverse
attribute [local instance] Classical.propDecidable
noncomputable def partialInv {α β} (f : α → β) (b : β) : Option α :=
if h : ∃ a, f a = b then some (Classical.choose h) else none
#align function.partial_inv Function.partialInv
theorem partialInv_of_injective {α β} {f : α → β} (I : Injective f) : IsPartialInv f (partialInv f)
| a, b =>
⟨fun h =>
have hpi : partialInv f b = if h : ∃ a, f a = b then some (Classical.choose h) else none :=
rfl
if h' : ∃ a, f a = b
then by rw [hpi, dif_pos h'] at h
injection h with h
subst h
apply Classical.choose_spec h'
else by rw [hpi, dif_neg h'] at h; contradiction,
fun e => e ▸ have h : ∃ a', f a' = f a := ⟨_, rfl⟩
(dif_pos h).trans (congr_arg _ (I <| Classical.choose_spec h))⟩
#align function.partial_inv_of_injective Function.partialInv_of_injective
theorem partialInv_left {α β} {f : α → β} (I : Injective f) : ∀ x, partialInv f (f x) = some x :=
isPartialInv_left (partialInv_of_injective I)
#align function.partial_inv_left Function.partialInv_left
end
noncomputable section Extend
attribute [local instance] Classical.propDecidable
variable {α β γ : Sort*} {f : α → β}
def extend (f : α → β) (g : α → γ) (j : β → γ) : β → γ := fun b ↦
if h : ∃ a, f a = b then g (Classical.choose h) else j b
#align function.extend Function.extend
def FactorsThrough (g : α → γ) (f : α → β) : Prop :=
∀ ⦃a b⦄, f a = f b → g a = g b
#align function.factors_through Function.FactorsThrough
theorem extend_def (f : α → β) (g : α → γ) (e' : β → γ) (b : β) [Decidable (∃ a, f a = b)] :
extend f g e' b = if h : ∃ a, f a = b then g (Classical.choose h) else e' b := by
unfold extend
congr
#align function.extend_def Function.extend_def
lemma Injective.factorsThrough (hf : Injective f) (g : α → γ) : g.FactorsThrough f :=
fun _ _ h => congr_arg g (hf h)
#align function.injective.factors_through Function.Injective.factorsThrough
lemma FactorsThrough.extend_apply {g : α → γ} (hf : g.FactorsThrough f) (e' : β → γ) (a : α) :
extend f g e' (f a) = g a := by
simp only [extend_def, dif_pos, exists_apply_eq_apply]
exact hf (Classical.choose_spec (exists_apply_eq_apply f a))
#align function.factors_through.extend_apply Function.FactorsThrough.extend_apply
@[simp]
theorem Injective.extend_apply (hf : Injective f) (g : α → γ) (e' : β → γ) (a : α) :
extend f g e' (f a) = g a :=
(hf.factorsThrough g).extend_apply e' a
#align function.injective.extend_apply Function.Injective.extend_apply
@[simp]
| Mathlib/Logic/Function/Basic.lean | 749 | 751 | theorem extend_apply' (g : α → γ) (e' : β → γ) (b : β) (hb : ¬∃ a, f a = b) :
extend f g e' b = e' b := by |
simp [Function.extend_def, hb]
|
import Mathlib.Algebra.Algebra.Defs
import Mathlib.Algebra.Algebra.NonUnitalHom
import Mathlib.Algebra.Star.Module
import Mathlib.Algebra.Star.NonUnitalSubalgebra
import Mathlib.LinearAlgebra.Prod
#align_import algebra.algebra.unitization from "leanprover-community/mathlib"@"8f66240cab125b938b327d3850169d490cfbcdd8"
def Unitization (R A : Type*) :=
R × A
#align unitization Unitization
namespace Unitization
section AlgHom
variable {S R A : Type*} [CommSemiring S] [CommSemiring R] [NonUnitalSemiring A] [Module R A]
[SMulCommClass R A A] [IsScalarTower R A A] {B : Type*} [Semiring B] [Algebra S B] [Algebra S R]
[DistribMulAction S A] [IsScalarTower S R A] {C : Type*} [Semiring C] [Algebra R C]
| Mathlib/Algebra/Algebra/Unitization.lean | 683 | 690 | theorem algHom_ext {F : Type*}
[FunLike F (Unitization R A) B] [AlgHomClass F S (Unitization R A) B] {φ ψ : F}
(h : ∀ a : A, φ a = ψ a)
(h' : ∀ r, φ (algebraMap R (Unitization R A) r) = ψ (algebraMap R (Unitization R A) r)) :
φ = ψ := by |
refine DFunLike.ext φ ψ (fun x ↦ ?_)
induction x
simp only [map_add, ← algebraMap_eq_inl, h, h']
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.