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reflTransGen_minimal {r' : α → α → Prop} (hr₁ : Reflexive r') (hr₂ : Transitive r') (h : ∀ x y, r x y → r' x y) {x y : α} (hxy : ReflTransGen r x y) : r' x y := by simpa [reflTransGen_eq_self hr₁ hr₂] using ReflTransGen.mono h hxy
lemma
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflTransGen_minimal
null
reflexive_reflTransGen : Reflexive (ReflTransGen r) := fun _ ↦ refl
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflexive_reflTransGen
null
transitive_reflTransGen : Transitive (ReflTransGen r) := fun _ _ _ ↦ trans
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
transitive_reflTransGen
null
reflTransGen_idem : ReflTransGen (ReflTransGen r) = ReflTransGen r := reflTransGen_eq_self reflexive_reflTransGen transitive_reflTransGen
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflTransGen_idem
null
ReflTransGen.lift' {p : β → β → Prop} {a b : α} (f : α → β) (h : ∀ a b, r a b → ReflTransGen p (f a) (f b)) (hab : ReflTransGen r a b) : ReflTransGen p (f a) (f b) := by simpa [reflTransGen_idem] using hab.lift f h
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
ReflTransGen.lift'
null
reflTransGen_closed {p : α → α → Prop} : (∀ a b, r a b → ReflTransGen p a b) → ReflTransGen r a b → ReflTransGen p a b := ReflTransGen.lift' id
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflTransGen_closed
null
ReflTransGen.swap (h : ReflTransGen r b a) : ReflTransGen (swap r) a b := by induction h with | refl => rfl | tail _ hbc ih => exact ih.head hbc
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
ReflTransGen.swap
null
reflTransGen_swap : ReflTransGen (swap r) a b ↔ ReflTransGen r b a := ⟨ReflTransGen.swap, ReflTransGen.swap⟩ @[simp] lemma reflGen_transGen : ReflGen (TransGen r) = ReflTransGen r := by ext x y simp_rw [reflTransGen_iff_eq_or_transGen, reflGen_iff] @[simp] lemma transGen_reflGen : TransGen (ReflGen r) = ReflTrans...
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflTransGen_swap
null
reflTransGen_eq_transGen (hr : Reflexive r) : ReflTransGen r = TransGen r := by rw [← transGen_reflGen, reflGen_eq_self hr]
lemma
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflTransGen_eq_transGen
null
reflTransGen_eq_reflGen (hr : Transitive r) : ReflTransGen r = ReflGen r := by rw [← reflGen_transGen, transGen_eq_self hr]
lemma
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflTransGen_eq_reflGen
null
is_equivalence : Equivalence (@EqvGen α r) := Equivalence.mk EqvGen.refl (EqvGen.symm _ _) (EqvGen.trans _ _ _)
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
is_equivalence
null
setoid : Setoid α := Setoid.mk _ (EqvGen.is_equivalence r)
def
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
setoid
`EqvGen.setoid r` is the setoid generated by a relation `r`. The motivation for this definition is that `Quot r` behaves like `Quotient (EqvGen.setoid r)`, see for example `Quot.eqvGen_exact` and `Quot.eqvGen_sound`.
mono {r p : α → α → Prop} (hrp : ∀ a b, r a b → p a b) (h : EqvGen r a b) : EqvGen p a b := by induction h with | rel a b h => exact EqvGen.rel _ _ (hrp _ _ h) | refl => exact EqvGen.refl _ | symm a b _ ih => exact EqvGen.symm _ _ ih | trans a b c _ _ hab hbc => exact EqvGen.trans _ _ _ hab hbc
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
mono
null
Join (r : α → α → Prop) : α → α → Prop := fun a b ↦ ∃ c, r a c ∧ r b c
def
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
Join
The join of a relation on a single type is a new relation for which pairs of terms are related if there is a third term they are both related to. For example, if `r` is a relation representing rewrites in a term rewriting system, then *confluence* is the property that if `a` rewrites to both `b` and `c`, then `join r`...
church_rosser (h : ∀ a b c, r a b → r a c → ∃ d, ReflGen r b d ∧ ReflTransGen r c d) (hab : ReflTransGen r a b) (hac : ReflTransGen r a c) : Join (ReflTransGen r) b c := by induction hab with | refl => exact ⟨c, hac, refl⟩ | @tail d e _ hde ih => rcases ih with ⟨b, hdb, hcb⟩ have : ∃ a, ReflTransGen r...
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
church_rosser
A sufficient condition for the Church-Rosser property.
join_of_single (h : Reflexive r) (hab : r a b) : Join r a b := ⟨b, hab, h b⟩
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
join_of_single
null
symmetric_join : Symmetric (Join r) := fun _ _ ⟨c, hac, hcb⟩ ↦ ⟨c, hcb, hac⟩
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
symmetric_join
null
reflexive_join (h : Reflexive r) : Reflexive (Join r) := fun a ↦ ⟨a, h a, h a⟩
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflexive_join
null
transitive_join (ht : Transitive r) (h : ∀ a b c, r a b → r a c → Join r b c) : Transitive (Join r) := fun _ b _ ⟨x, hax, hbx⟩ ⟨y, hby, hcy⟩ ↦ let ⟨z, hxz, hyz⟩ := h b x y hbx hby ⟨z, ht hax hxz, ht hcy hyz⟩
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
transitive_join
null
equivalence_join (hr : Reflexive r) (ht : Transitive r) (h : ∀ a b c, r a b → r a c → Join r b c) : Equivalence (Join r) := ⟨reflexive_join hr, @symmetric_join _ _, @transitive_join _ _ ht h⟩
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
equivalence_join
null
equivalence_join_reflTransGen (h : ∀ a b c, r a b → r a c → ∃ d, ReflGen r b d ∧ ReflTransGen r c d) : Equivalence (Join (ReflTransGen r)) := equivalence_join reflexive_reflTransGen transitive_reflTransGen fun _ _ _ ↦ church_rosser h
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
equivalence_join_reflTransGen
null
join_of_equivalence {r' : α → α → Prop} (hr : Equivalence r) (h : ∀ a b, r' a b → r a b) : Join r' a b → r a b | ⟨_, hac, hbc⟩ => hr.trans (h _ _ hac) (hr.symm <| h _ _ hbc)
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
join_of_equivalence
null
reflTransGen_of_transitive_reflexive {r' : α → α → Prop} (hr : Reflexive r) (ht : Transitive r) (h : ∀ a b, r' a b → r a b) (h' : ReflTransGen r' a b) : r a b := by induction h' with | refl => exact hr _ | tail _ hbc ih => exact ht ih (h _ _ hbc)
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflTransGen_of_transitive_reflexive
null
reflTransGen_of_equivalence {r' : α → α → Prop} (hr : Equivalence r) : (∀ a b, r' a b → r a b) → ReflTransGen r' a b → r a b := reflTransGen_of_transitive_reflexive hr.1 (fun _ _ _ ↦ hr.trans)
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
reflTransGen_of_equivalence
null
Quot.eqvGen_exact (H : Quot.mk r a = Quot.mk r b) : EqvGen r a b := @Quotient.exact _ (EqvGen.setoid r) a b (congrArg (Quot.lift (Quotient.mk (EqvGen.setoid r)) (fun x y h ↦ Quot.sound (EqvGen.rel x y h))) H)
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
Quot.eqvGen_exact
null
Quot.eqvGen_sound (H : EqvGen r a b) : Quot.mk r a = Quot.mk r b := EqvGen.rec (fun _ _ h ↦ Quot.sound h) (fun _ ↦ rfl) (fun _ _ _ IH ↦ Eq.symm IH) (fun _ _ _ _ _ IH₁ IH₂ ↦ Eq.trans IH₁ IH₂) H
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
Quot.eqvGen_sound
null
Equivalence.eqvGen_iff (h : Equivalence r) : EqvGen r a b ↔ r a b := Iff.intro (by intro h induction h with | rel => assumption | refl => exact h.1 _ | symm => apply h.symm; assumption | trans _ _ _ _ _ hab hbc => exact h.trans hab hbc) (EqvGen.rel a b)
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
Equivalence.eqvGen_iff
null
Equivalence.eqvGen_eq (h : Equivalence r) : EqvGen r = r := funext fun _ ↦ funext fun _ ↦ propext <| h.eqvGen_iff
theorem
Logic
[ "Mathlib.Logic.Relator", "Mathlib.Tactic.Use", "Mathlib.Tactic.MkIffOfInductiveProp", "Mathlib.Tactic.SimpRw", "Mathlib.Logic.Basic", "Mathlib.Order.Defs.Unbundled" ]
Mathlib/Logic/Relation.lean
Equivalence.eqvGen_eq
null
LiftFun (f : α → γ) (g : β → δ) : Prop := ∀ ⦃a b⦄, R a b → S (f a) (g b)
def
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
LiftFun
The binary relations `R : α → β → Prop` and `S : γ → δ → Prop` induce a binary relation on functions `LiftFun : (α → γ) → (β → δ) → Prop`.
RightTotal : Prop := ∀ b, ∃ a, R a b
def
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
RightTotal
`(R ⇒ S) f g` means `LiftFun R S f g`. -/ scoped infixr:40 " ⇒ " => LiftFun end section variable {α : Type u₁} {β : Type u₂} (R : α → β → Prop) /-- A relation is "right total" if every element appears on the right.
LeftTotal : Prop := ∀ a, ∃ b, R a b
def
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
LeftTotal
A relation is "left total" if every element appears on the left.
BiTotal : Prop := LeftTotal R ∧ RightTotal R
def
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
BiTotal
A relation is "bi-total" if it is both right total and left total.
LeftUnique : Prop := ∀ ⦃a b c⦄, R a c → R b c → a = b
def
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
LeftUnique
A relation is "left unique" if every element on the right is paired with at most one element on the left.
RightUnique : Prop := ∀ ⦃a b c⦄, R a b → R a c → b = c
def
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
RightUnique
A relation is "right unique" if every element on the left is paired with at most one element on the right.
BiUnique : Prop := LeftUnique R ∧ RightUnique R variable {R}
def
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
BiUnique
A relation is "bi-unique" if it is both left unique and right unique.
RightTotal.rel_forall (h : RightTotal R) : ((R ⇒ (· → ·)) ⇒ (· → ·)) (fun p => ∀ i, p i) (fun q => ∀ i, q i) := fun _ _ Hrel H b => Exists.elim (h b) (fun _ Rab => Hrel Rab (H _))
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
RightTotal.rel_forall
null
LeftTotal.rel_exists (h : LeftTotal R) : ((R ⇒ (· → ·)) ⇒ (· → ·)) (fun p => ∃ i, p i) (fun q => ∃ i, q i) := fun _ _ Hrel ⟨a, pa⟩ => (h a).imp fun _ Rab => Hrel Rab pa
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
LeftTotal.rel_exists
null
BiTotal.rel_forall (h : BiTotal R) : ((R ⇒ Iff) ⇒ Iff) (fun p => ∀ i, p i) (fun q => ∀ i, q i) := fun _ _ Hrel => ⟨fun H b => Exists.elim (h.right b) (fun _ Rab => (Hrel Rab).mp (H _)), fun H a => Exists.elim (h.left a) (fun _ Rab => (Hrel Rab).mpr (H _))⟩
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
BiTotal.rel_forall
null
BiTotal.rel_exists (h : BiTotal R) : ((R ⇒ Iff) ⇒ Iff) (fun p => ∃ i, p i) (fun q => ∃ i, q i) := fun _ _ Hrel => ⟨fun ⟨a, pa⟩ => (h.left a).imp fun _ Rab => (Hrel Rab).1 pa, fun ⟨b, qb⟩ => (h.right b).imp fun _ Rab => (Hrel Rab).2 qb⟩
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
BiTotal.rel_exists
null
left_unique_of_rel_eq {eq' : β → β → Prop} (he : (R ⇒ (R ⇒ Iff)) Eq eq') : LeftUnique R := fun a b c (ac : R a c) (bc : R b c) => (he ac bc).mpr ((he bc bc).mp rfl)
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
left_unique_of_rel_eq
null
rel_imp : (Iff ⇒ (Iff ⇒ Iff)) (· → ·) (· → ·) := fun _ _ h _ _ l => imp_congr h l
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
rel_imp
null
rel_not : (Iff ⇒ Iff) Not Not := fun _ _ h => not_congr h
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
rel_not
null
bi_total_eq {α : Type u₁} : Relator.BiTotal (@Eq α) := { left := fun a => ⟨a, rfl⟩, right := fun a => ⟨a, rfl⟩ } variable {α : Type*} {β : Type*} {γ : Type*} variable {r : α → β → Prop}
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
bi_total_eq
null
LeftUnique.flip (h : LeftUnique r) : RightUnique (flip r) := fun _ _ _ h₁ h₂ => h h₁ h₂
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
LeftUnique.flip
null
rel_and : ((· ↔ ·) ⇒ (· ↔ ·) ⇒ (· ↔ ·)) (· ∧ ·) (· ∧ ·) := fun _ _ h₁ _ _ h₂ => and_congr h₁ h₂
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
rel_and
null
rel_or : ((· ↔ ·) ⇒ (· ↔ ·) ⇒ (· ↔ ·)) (· ∨ ·) (· ∨ ·) := fun _ _ h₁ _ _ h₂ => or_congr h₁ h₂
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
rel_or
null
rel_iff : ((· ↔ ·) ⇒ (· ↔ ·) ⇒ (· ↔ ·)) (· ↔ ·) (· ↔ ·) := fun _ _ h₁ _ _ h₂ => iff_congr h₁ h₂
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
rel_iff
null
rel_eq {r : α → β → Prop} (hr : BiUnique r) : (r ⇒ r ⇒ (· ↔ ·)) (· = ·) (· = ·) := fun _ _ h₁ _ _ h₂ => ⟨fun h => hr.right h₁ <| h.symm ▸ h₂, fun h => hr.left h₁ <| h.symm ▸ h₂⟩ open Function variable {r₁₁ : α → α → Prop} {r₁₂ : α → β → Prop} {r₂₁ : β → α → Prop} {r₂₃ : β → γ → Prop} {r₁₃ : α → γ → Prop}
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
rel_eq
null
protected refl (hr : ∀ a : α, r₁₁ a a) : LeftTotal r₁₁ := fun a ↦ ⟨a, hr _⟩
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
refl
null
protected symm (hr : ∀ (a : α) (b : β), r₁₂ a b → r₂₁ b a) : LeftTotal r₁₂ → RightTotal r₂₁ := fun h a ↦ (h a).imp (fun _ ↦ hr _ _)
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
symm
null
protected trans (hr : ∀ (a : α) (b : β) (c : γ), r₁₂ a b → r₂₃ b c → r₁₃ a c) : LeftTotal r₁₂ → LeftTotal r₂₃ → LeftTotal r₁₃ := fun h₁ h₂ a ↦ let ⟨b, hab⟩ := h₁ a; let ⟨c, hbc⟩ := h₂ b; ⟨c, hr _ _ _ hab hbc⟩
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
trans
null
protected refl (hr : ∀ a : α, r₁₁ a a) : RightTotal r₁₁ := LeftTotal.refl hr
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
refl
null
protected symm (hr : ∀ (a : α) (b : β), r₁₂ a b → r₂₁ b a) : RightTotal r₁₂ → LeftTotal r₂₁ := LeftTotal.symm (fun _ _ ↦ hr _ _)
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
symm
null
protected trans (hr : ∀ (a : α) (b : β) (c : γ), r₁₂ a b → r₂₃ b c → r₁₃ a c) : RightTotal r₁₂ → RightTotal r₂₃ → RightTotal r₁₃ := swap <| LeftTotal.trans (fun _ _ _ ↦ swap <| hr _ _ _)
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
trans
null
protected refl (hr : ∀ a : α, r₁₁ a a) : BiTotal r₁₁ := ⟨LeftTotal.refl hr, RightTotal.refl hr⟩
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
refl
null
protected symm (hr : ∀ (a : α) (b : β), r₁₂ a b → r₂₁ b a) : BiTotal r₁₂ → BiTotal r₂₁ := fun h ↦ ⟨h.2.symm hr, h.1.symm hr⟩
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
symm
null
protected trans (hr : ∀ (a : α) (b : β) (c : γ), r₁₂ a b → r₂₃ b c → r₁₃ a c) : BiTotal r₁₂ → BiTotal r₂₃ → BiTotal r₁₃ := fun h₁ h₂ ↦ ⟨h₁.1.trans hr h₂.1, h₁.2.trans hr h₂.2⟩
lemma
Logic
[ "Mathlib.Logic.Function.Defs" ]
Mathlib/Logic/Relator.lean
trans
null
@[ext] Unique (α : Sort u) extends Inhabited α where /-- In a `Unique` type, every term is equal to the default element (from `Inhabited`). -/ uniq : ∀ a : α, a = default attribute [class] Unique
structure
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Unique
`Unique α` expresses that `α` is a type with a unique term `default`. This is implemented as a type, rather than a `Prop`-valued predicate, for good definitional properties of the default term.
unique_iff_existsUnique (α : Sort u) : Nonempty (Unique α) ↔ ∃! _ : α, True := ⟨fun ⟨u⟩ ↦ ⟨u.default, trivial, fun a _ ↦ u.uniq a⟩, fun ⟨a, _, h⟩ ↦ ⟨⟨⟨a⟩, fun _ ↦ h _ trivial⟩⟩⟩
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
unique_iff_existsUnique
null
unique_subtype_iff_existsUnique {α} (p : α → Prop) : Nonempty (Unique (Subtype p)) ↔ ∃! a, p a := ⟨fun ⟨u⟩ ↦ ⟨u.default.1, u.default.2, fun a h ↦ congr_arg Subtype.val (u.uniq ⟨a, h⟩)⟩, fun ⟨a, ha, he⟩ ↦ ⟨⟨⟨⟨a, ha⟩⟩, fun ⟨b, hb⟩ ↦ by congr exact he b hb⟩⟩⟩
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
unique_subtype_iff_existsUnique
null
uniqueOfSubsingleton {α : Sort*} [Subsingleton α] (a : α) : Unique α where default := a uniq _ := Subsingleton.elim _ _
abbrev
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
uniqueOfSubsingleton
Given an explicit `a : α` with `Subsingleton α`, we can construct a `Unique α` instance. This is a def because the typeclass search cannot arbitrarily invent the `a : α` term. Nevertheless, these instances are all equivalent by `Unique.Subsingleton.unique`. See note [reducible non-instances].
PUnit.instUnique : Unique PUnit.{u} where default := PUnit.unit uniq x := subsingleton x _ @[simp]
instance
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
PUnit.instUnique
null
PUnit.default_eq_unit : (default : PUnit) = PUnit.unit := rfl
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
PUnit.default_eq_unit
null
uniqueProp {p : Prop} (h : p) : Unique.{0} p where default := h uniq _ := rfl
def
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
uniqueProp
Every provable proposition is unique, as all proofs are equal.
eq_default (a : α) : a = default := uniq _ a
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
eq_default
null
default_eq (a : α) : default = a := (uniq _ a).symm
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
default_eq
null
forall_iff {p : α → Prop} : (∀ a, p a) ↔ p default := ⟨fun h ↦ h _, fun h x ↦ by rwa [Unique.eq_default x]⟩
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
forall_iff
null
exists_iff {p : α → Prop} : Exists p ↔ p default := ⟨fun ⟨a, ha⟩ ↦ eq_default a ▸ ha, Exists.intro default⟩
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
exists_iff
null
@[ext] protected subsingleton_unique' : ∀ h₁ h₂ : Unique α, h₁ = h₂ | ⟨⟨x⟩, h⟩, ⟨⟨y⟩, _⟩ => by congr; rw [h x, h y]
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
subsingleton_unique'
null
subsingleton_unique : Subsingleton (Unique α) := ⟨Unique.subsingleton_unique'⟩
instance
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
subsingleton_unique
null
mk' (α : Sort u) [h₁ : Inhabited α] [Subsingleton α] : Unique α := { h₁ with uniq := fun _ ↦ Subsingleton.elim _ _ }
abbrev
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
mk'
Construct `Unique` from `Inhabited` and `Subsingleton`. Making this an instance would create a loop in the class inheritance graph.
nonempty_unique (α : Sort u) [Subsingleton α] [Nonempty α] : Nonempty (Unique α) := by inhabit α exact ⟨Unique.mk' α⟩
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
nonempty_unique
null
unique_iff_subsingleton_and_nonempty (α : Sort u) : Nonempty (Unique α) ↔ Subsingleton α ∧ Nonempty α := ⟨fun ⟨u⟩ ↦ by constructor <;> exact inferInstance, fun ⟨hs, hn⟩ ↦ nonempty_unique α⟩ variable {α : Sort*} @[simp]
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
unique_iff_subsingleton_and_nonempty
null
Pi.default_def {β : α → Sort v} [∀ a, Inhabited (β a)] : @default (∀ a, β a) _ = fun a : α ↦ @default (β a) _ := rfl
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Pi.default_def
null
Pi.default_apply {β : α → Sort v} [∀ a, Inhabited (β a)] (a : α) : @default (∀ a, β a) _ a = default := rfl
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Pi.default_apply
null
Pi.unique {β : α → Sort v} [∀ a, Unique (β a)] : Unique (∀ a, β a) where uniq := fun _ ↦ funext fun _ ↦ Unique.eq_default _
instance
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Pi.unique
null
Pi.uniqueOfIsEmpty [IsEmpty α] (β : α → Sort v) : Unique (∀ a, β a) where default := isEmptyElim uniq _ := funext isEmptyElim
instance
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Pi.uniqueOfIsEmpty
There is a unique function on an empty domain.
eq_const_of_subsingleton {β : Sort*} [Subsingleton α] (f : α → β) (a : α) : f = Function.const α (f a) := funext fun x ↦ Subsingleton.elim x a ▸ rfl
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
eq_const_of_subsingleton
null
eq_const_of_unique {β : Sort*} [Unique α] (f : α → β) : f = Function.const α (f default) := eq_const_of_subsingleton ..
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
eq_const_of_unique
null
heq_const_of_unique [Unique α] {β : α → Sort v} (f : ∀ a, β a) : f ≍ Function.const α (f default) := (Function.hfunext rfl) fun i _ _ ↦ by rw [Subsingleton.elim i default]; rfl
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
heq_const_of_unique
null
protected Injective.subsingleton (hf : Injective f) [Subsingleton β] : Subsingleton α := ⟨fun _ _ ↦ hf <| Subsingleton.elim _ _⟩
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Injective.subsingleton
If the codomain of an injective function is a subsingleton, then the domain is a subsingleton as well.
protected Surjective.subsingleton [Subsingleton α] (hf : Surjective f) : Subsingleton β := ⟨hf.forall₂.2 fun x y ↦ congr_arg f <| Subsingleton.elim x y⟩
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Surjective.subsingleton
If the domain of a surjective function is a subsingleton, then the codomain is a subsingleton as well.
protected Surjective.unique {α : Sort u} (f : α → β) (hf : Surjective f) [Unique.{u} α] : Unique β := @Unique.mk' _ ⟨f default⟩ hf.subsingleton
def
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Surjective.unique
If the domain of a surjective function is a singleton, then the codomain is a singleton as well.
protected Injective.unique [Inhabited α] [Subsingleton β] (hf : Injective f) : Unique α := @Unique.mk' _ _ hf.subsingleton
def
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Injective.unique
If `α` is inhabited and admits an injective map to a subsingleton type, then `α` is `Unique`.
Surjective.uniqueOfSurjectiveConst (α : Type*) {β : Type*} (b : β) (h : Function.Surjective (Function.const α b)) : Unique β := @uniqueOfSubsingleton _ (subsingleton_of_forall_eq b <| h.forall.mpr fun _ ↦ rfl) b
def
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Surjective.uniqueOfSurjectiveConst
If a constant function is surjective, then the codomain is a singleton.
uniqueElim [Unique ι] (x : α (default : ι)) (i : ι) : α i := by rw [Unique.eq_default i] exact x @[simp]
def
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
uniqueElim
Given one value over a unique, we get a dependent function.
uniqueElim_default {_ : Unique ι} (x : α (default : ι)) : uniqueElim x (default : ι) = x := rfl @[simp]
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
uniqueElim_default
null
uniqueElim_const {β : Sort*} {_ : Unique ι} (x : β) (i : ι) : uniqueElim (α := fun _ ↦ β) x i = x := rfl
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
uniqueElim_const
null
Unique.bijective {A B} [Unique A] [Unique B] {f : A → B} : Function.Bijective f := by rw [Function.bijective_iff_has_inverse] refine ⟨default, ?_, ?_⟩ <;> intro x <;> simp
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Unique.bijective
null
subsingleton_iff_isEmpty {α : Type u} : Subsingleton (Option α) ↔ IsEmpty α := ⟨fun h ↦ ⟨fun x ↦ Option.noConfusion <| @Subsingleton.elim _ h x none⟩, fun h ↦ ⟨fun x y ↦ Option.casesOn x (Option.casesOn y rfl fun x ↦ h.elim x) fun x ↦ h.elim x⟩⟩
theorem
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
subsingleton_iff_isEmpty
`Option α` is a `Subsingleton` if and only if `α` is empty.
Unique.subtypeEq (y : α) : Unique { x // x = y } where default := ⟨y, rfl⟩ uniq := fun ⟨x, hx⟩ ↦ by congr
instance
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Unique.subtypeEq
null
Unique.subtypeEq' (y : α) : Unique { x // y = x } where default := ⟨y, rfl⟩ uniq := fun ⟨x, hx⟩ ↦ by subst hx; congr
instance
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Unique.subtypeEq'
null
Fin.instUnique : Unique (Fin 1) where uniq _ := Subsingleton.elim _ _
instance
Logic
[ "Mathlib.Logic.IsEmpty", "Mathlib.Tactic.Inhabit" ]
Mathlib/Logic/Unique.lean
Fin.instUnique
null
@[pp_with_univ, mk_iff] UnivLE : Prop where small (α : Type u) : Small.{v} α attribute [instance] UnivLE.small /- This is useless as an instance due to https://github.com/leanprover/lean4/issues/2297 -/
class
Logic
[ "Mathlib.Logic.Small.Defs" ]
Mathlib/Logic/UnivLE.lean
UnivLE
A class expressing a universe inequality. `UnivLE.{u, v}` expresses that `u ≤ v`. There used to be a stronger definition `∀ α : Type max u v, Small.{v} α` that immediately implies `Small.{v} ((α : Type u) → (β : Type v))` which is essential for proving that `Type v` has `Type u`-indexed limits when `u ≤ v`. However th...
univLE_max : UnivLE.{u, max u v} where small α := small_max.{v} α
theorem
Logic
[ "Mathlib.Logic.Small.Defs" ]
Mathlib/Logic/UnivLE.lean
univLE_max
null
Small.trans_univLE (α : Type w) [hα : Small.{u} α] [h : UnivLE.{u, v}] : Small.{v} α := let ⟨β, ⟨f⟩⟩ := hα.equiv_small let ⟨_, ⟨g⟩⟩ := (h.small β).equiv_small ⟨_, ⟨f.trans g⟩⟩
theorem
Logic
[ "Mathlib.Logic.Small.Defs" ]
Mathlib/Logic/UnivLE.lean
Small.trans_univLE
null
UnivLE.trans [UnivLE.{u, v}] [UnivLE.{v, w}] : UnivLE.{u, w} where small α := Small.trans_univLE α
theorem
Logic
[ "Mathlib.Logic.Small.Defs" ]
Mathlib/Logic/UnivLE.lean
UnivLE.trans
null
UnivLE.self : UnivLE.{u, u} := ⟨inferInstance⟩
instance
Logic
[ "Mathlib.Logic.Small.Defs" ]
Mathlib/Logic/UnivLE.lean
UnivLE.self
null
UnivLE.zero : UnivLE.{0, u} := ⟨inferInstance⟩
instance
Logic
[ "Mathlib.Logic.Small.Defs" ]
Mathlib/Logic/UnivLE.lean
UnivLE.zero
null
UnivLE.succ [UnivLE.{u, v}] : UnivLE.{u, v + 1} := @UnivLE.trans _ ⟨inferInstance⟩ /- This is the crucial instance that subsumes `univLE_max`. -/
theorem
Logic
[ "Mathlib.Logic.Small.Defs" ]
Mathlib/Logic/UnivLE.lean
UnivLE.succ
This is redundant as an instance given the below.