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coe_unit_group_mul_equiv_apply (a : A.unit_group) : (A.unit_group_mul_equiv a : K) = a
rfl
lemma
valuation_subring.coe_unit_group_mul_equiv_apply
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_unit_group_mul_equiv_symm_apply (a : Aˣ) : (A.unit_group_mul_equiv.symm a : K) = a
rfl
lemma
valuation_subring.coe_unit_group_mul_equiv_symm_apply
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_group_le_unit_group {A B : valuation_subring K} : A.unit_group ≤ B.unit_group ↔ A ≤ B
begin split, { intros h x hx, rw [← A.valuation_le_one_iff x, le_iff_lt_or_eq] at hx, by_cases h_1 : x = 0, { simp only [h_1, zero_mem] }, by_cases h_2 : 1 + x = 0, { simp only [← add_eq_zero_iff_neg_eq.1 h_2, neg_mem _ _ (one_mem _)] }, cases hx, { have := h (show (units.mk0 _ h_2) ∈ A.un...
lemma
valuation_subring.unit_group_le_unit_group
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set_like.coe_mem", "units.mk0", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_group_injective : function.injective (unit_group : valuation_subring K → subgroup _)
λ A B h, by { simpa only [le_antisymm_iff, unit_group_le_unit_group] using h}
lemma
valuation_subring.unit_group_injective
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "subgroup", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_iff_unit_group {A B : valuation_subring K} : A = B ↔ A.unit_group = B.unit_group
unit_group_injective.eq_iff.symm
lemma
valuation_subring.eq_iff_unit_group
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_group_order_embedding : valuation_subring K ↪o subgroup Kˣ
{ to_fun := λ A, A.unit_group, inj' := unit_group_injective, map_rel_iff' := λ A B, unit_group_le_unit_group }
def
valuation_subring.unit_group_order_embedding
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "subgroup", "valuation_subring" ]
The map on valuation subrings to their unit groups is an order embedding.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_group_strict_mono : strict_mono (unit_group : valuation_subring K → subgroup _)
unit_group_order_embedding.strict_mono
lemma
valuation_subring.unit_group_strict_mono
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "strict_mono", "subgroup", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonunits : subsemigroup K
{ carrier := { x | A.valuation x < 1 }, mul_mem' := λ a b ha hb, (mul_lt_mul₀ ha hb).trans_eq $ mul_one _ }
def
valuation_subring.nonunits
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "mul_lt_mul₀", "mul_one", "nonunits", "subsemigroup" ]
The nonunits of a valuation subring of `K`, as a subsemigroup of `K`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_nonunits_iff {x : K} : x ∈ A.nonunits ↔ A.valuation x < 1
iff.rfl
lemma
valuation_subring.mem_nonunits_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "mem_nonunits_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonunits_le_nonunits {A B : valuation_subring K} : B.nonunits ≤ A.nonunits ↔ A ≤ B
begin split, { intros h x hx, by_cases h_1 : x = 0, { simp only [h_1, zero_mem] }, rw [← valuation_le_one_iff, ← not_lt, valuation.one_lt_val_iff _ h_1] at hx ⊢, by_contra h_2, from hx (h h_2) }, { intros h x hx, by_contra h_1, from not_lt.2 (monotone_map_of_le _ _ h (not_lt.1 h_1)) hx } end
lemma
valuation_subring.nonunits_le_nonunits
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "by_contra", "valuation.one_lt_val_iff", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonunits_injective : function.injective (nonunits : valuation_subring K → subsemigroup _)
λ A B h, by { simpa only [le_antisymm_iff, nonunits_le_nonunits] using h.symm }
lemma
valuation_subring.nonunits_injective
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "nonunits", "subsemigroup", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonunits_inj {A B : valuation_subring K} : A.nonunits = B.nonunits ↔ A = B
nonunits_injective.eq_iff
lemma
valuation_subring.nonunits_inj
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonunits_order_embedding : valuation_subring K ↪o (subsemigroup K)ᵒᵈ
{ to_fun := λ A, A.nonunits, inj' := nonunits_injective, map_rel_iff' := λ A B, nonunits_le_nonunits }
def
valuation_subring.nonunits_order_embedding
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "subsemigroup", "valuation_subring" ]
The map on valuation subrings to their nonunits is a dual order embedding.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mem_nonunits_iff {a : A} : (a : K) ∈ A.nonunits ↔ a ∈ local_ring.maximal_ideal A
(valuation_lt_one_iff _ _).symm
theorem
valuation_subring.coe_mem_nonunits_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "local_ring.maximal_ideal" ]
The elements of `A.nonunits` are those of the maximal ideal of `A` after coercion to `K`. See also `mem_nonunits_iff_exists_mem_maximal_ideal`, which gets rid of the coercion to `K`, at the expense of a more complicated right hand side.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonunits_le : A.nonunits ≤ A.to_subring.to_submonoid.to_subsemigroup
λ a ha, (A.valuation_le_one_iff _).mp (A.mem_nonunits_iff.mp ha).le
lemma
valuation_subring.nonunits_le
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonunits_subset : (A.nonunits : set K) ⊆ A
nonunits_le
lemma
valuation_subring.nonunits_subset
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_nonunits_iff_exists_mem_maximal_ideal {a : K} : a ∈ A.nonunits ↔ ∃ ha, (⟨a, ha⟩ : A) ∈ local_ring.maximal_ideal A
⟨λ h, ⟨nonunits_subset h, coe_mem_nonunits_iff.mp h⟩, λ ⟨ha, h⟩, coe_mem_nonunits_iff.mpr h⟩
theorem
valuation_subring.mem_nonunits_iff_exists_mem_maximal_ideal
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "local_ring.maximal_ideal" ]
The elements of `A.nonunits` are those of the maximal ideal of `A`. See also `coe_mem_nonunits_iff`, which has a simpler right hand side but requires the element to be in `A` already.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_maximal_ideal : (coe : A → K) '' local_ring.maximal_ideal A = A.nonunits
begin ext a, simp only [set.mem_image, set_like.mem_coe, mem_nonunits_iff_exists_mem_maximal_ideal], erw subtype.exists, simp_rw [subtype.coe_mk, exists_and_distrib_right, exists_eq_right], end
theorem
valuation_subring.image_maximal_ideal
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "exists_and_distrib_right", "exists_eq_right", "local_ring.maximal_ideal", "set.mem_image", "set_like.mem_coe", "subtype.coe_mk" ]
`A.nonunits` agrees with the maximal ideal of `A`, after taking its image in `K`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_unit_group : subgroup Kˣ
{ carrier := { x | A.valuation (x - 1) < 1 }, mul_mem' := begin intros a b ha hb, refine lt_of_le_of_lt _ (max_lt hb ha), rw [← one_mul (A.valuation (b - 1)), ← A.valuation.map_one_add_of_lt ha, add_sub_cancel'_right, ← valuation.map_mul, mul_sub_one, ← sub_add_sub_cancel], exact A.valuation.map...
def
valuation_subring.principal_unit_group
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "mul_one", "mul_sub_one", "one_mul", "subgroup", "units.inv_mul", "valuation.map_mul", "valuation.map_neg" ]
The principal unit group of a valuation subring, as a subgroup of `Kˣ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_units_le_units : A.principal_unit_group ≤ A.unit_group
λ a h, by simpa only [add_sub_cancel'_right] using A.valuation.map_one_add_of_lt h
lemma
valuation_subring.principal_units_le_units
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_principal_unit_group_iff (x : Kˣ) : x ∈ A.principal_unit_group ↔ A.valuation ((x : K) - 1) < 1
iff.rfl
lemma
valuation_subring.mem_principal_unit_group_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_unit_group_le_principal_unit_group {A B : valuation_subring K} : B.principal_unit_group ≤ A.principal_unit_group ↔ A ≤ B
begin split, { intros h x hx, by_cases h_1 : x = 0, { simp only [h_1, zero_mem] }, by_cases h_2 : x⁻¹ + 1 = 0, { rw [add_eq_zero_iff_eq_neg, inv_eq_iff_eq_inv, inv_neg, inv_one] at h_2, simpa only [h_2] using B.neg_mem _ B.one_mem }, { rw [← valuation_le_one_iff, ← not_lt, valuation.one_lt_val...
lemma
valuation_subring.principal_unit_group_le_principal_unit_group
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "by_contra", "inv_eq_iff_eq_inv", "inv_neg", "inv_one", "units.coe_mk0", "units.mk0", "valuation.one_lt_val_iff", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_unit_group_injective : function.injective (principal_unit_group : valuation_subring K → subgroup _)
λ A B h, by { simpa [le_antisymm_iff, principal_unit_group_le_principal_unit_group] using h.symm }
lemma
valuation_subring.principal_unit_group_injective
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "subgroup", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_iff_principal_unit_group {A B : valuation_subring K} : A = B ↔ A.principal_unit_group = B.principal_unit_group
principal_unit_group_injective.eq_iff.symm
lemma
valuation_subring.eq_iff_principal_unit_group
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_unit_group_order_embedding : valuation_subring K ↪o (subgroup Kˣ)ᵒᵈ
{ to_fun := λ A, A.principal_unit_group, inj' := principal_unit_group_injective, map_rel_iff' := λ A B, principal_unit_group_le_principal_unit_group }
def
valuation_subring.principal_unit_group_order_embedding
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "subgroup", "valuation_subring" ]
The map on valuation subrings to their principal unit groups is an order embedding.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mem_principal_unit_group_iff {x : A.unit_group} : (x : Kˣ) ∈ A.principal_unit_group ↔ A.unit_group_mul_equiv x ∈ (units.map (local_ring.residue A).to_monoid_hom).ker
begin rw [monoid_hom.mem_ker, units.ext_iff], let π := ideal.quotient.mk (local_ring.maximal_ideal A), convert_to _ ↔ π _ = 1, rw [← π.map_one, ← sub_eq_zero, ← π.map_sub, ideal.quotient.eq_zero_iff_mem, valuation_lt_one_iff], simpa, end
lemma
valuation_subring.coe_mem_principal_unit_group_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "ideal.quotient.eq_zero_iff_mem", "ideal.quotient.mk", "local_ring.maximal_ideal", "local_ring.residue", "monoid_hom.mem_ker", "units.ext_iff", "units.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_unit_group_equiv : A.principal_unit_group ≃* (units.map (local_ring.residue A).to_monoid_hom).ker
{ to_fun := λ x, ⟨A.unit_group_mul_equiv ⟨_, A.principal_units_le_units x.2⟩, A.coe_mem_principal_unit_group_iff.1 x.2⟩, inv_fun := λ x, ⟨A.unit_group_mul_equiv.symm x, by { rw A.coe_mem_principal_unit_group_iff, simpa using set_like.coe_mem x }⟩, left_inv := λ x, by simp, right_inv := λ x, by simp, map...
def
valuation_subring.principal_unit_group_equiv
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "inv_fun", "local_ring.residue", "set_like.coe_mem", "units.map" ]
The principal unit group agrees with the kernel of the canonical map from the units of `A` to the units of the residue field of `A`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_unit_group_equiv_apply (a : A.principal_unit_group) : (principal_unit_group_equiv A a : K) = a
rfl
lemma
valuation_subring.principal_unit_group_equiv_apply
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_unit_group_symm_apply (a : (units.map (local_ring.residue A).to_monoid_hom).ker) : (A.principal_unit_group_equiv.symm a : K) = a
rfl
lemma
valuation_subring.principal_unit_group_symm_apply
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "local_ring.residue", "units.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_group_to_residue_field_units : A.unit_group →* (local_ring.residue_field A)ˣ
monoid_hom.comp (units.map $ (ideal.quotient.mk _).to_monoid_hom) A.unit_group_mul_equiv.to_monoid_hom
def
valuation_subring.unit_group_to_residue_field_units
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "ideal.quotient.mk", "local_ring.residue_field", "monoid_hom.comp", "units.map" ]
The canonical map from the unit group of `A` to the units of the residue field of `A`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_unit_group_to_residue_field_units_apply (x : A.unit_group) : (A.unit_group_to_residue_field_units x : (local_ring.residue_field A) ) = (ideal.quotient.mk _ (A.unit_group_mul_equiv x : A))
rfl
lemma
valuation_subring.coe_unit_group_to_residue_field_units_apply
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "ideal.quotient.mk", "local_ring.residue_field" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ker_unit_group_to_residue_field_units : A.unit_group_to_residue_field_units.ker = A.principal_unit_group.comap A.unit_group.subtype
by { ext, simpa only [subgroup.mem_comap, subgroup.coe_subtype, coe_mem_principal_unit_group_iff] }
lemma
valuation_subring.ker_unit_group_to_residue_field_units
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "subgroup.coe_subtype", "subgroup.mem_comap" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
surjective_unit_group_to_residue_field_units : function.surjective A.unit_group_to_residue_field_units
(local_ring.surjective_units_map_of_local_ring_hom _ ideal.quotient.mk_surjective local_ring.is_local_ring_hom_residue).comp (mul_equiv.surjective _)
lemma
valuation_subring.surjective_unit_group_to_residue_field_units
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "ideal.quotient.mk_surjective", "local_ring.is_local_ring_hom_residue", "local_ring.surjective_units_map_of_local_ring_hom", "mul_equiv.surjective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_mod_principal_units_equiv_residue_field_units : (A.unit_group ⧸ (A.principal_unit_group.comap A.unit_group.subtype)) ≃* (local_ring.residue_field A)ˣ
(quotient_group.quotient_mul_equiv_of_eq A.ker_unit_group_to_residue_field_units.symm).trans (quotient_group.quotient_ker_equiv_of_surjective _ A.surjective_unit_group_to_residue_field_units)
def
valuation_subring.units_mod_principal_units_equiv_residue_field_units
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "local_ring.residue_field", "quotient_group.quotient_ker_equiv_of_surjective", "quotient_group.quotient_mul_equiv_of_eq" ]
The quotient of the unit group of `A` by the principal unit group of `A` agrees with the units of the residue field of `A`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_mod_principal_units_equiv_residue_field_units_comp_quotient_group_mk : A.units_mod_principal_units_equiv_residue_field_units.to_monoid_hom.comp (quotient_group.mk' _) = A.unit_group_to_residue_field_units
rfl
lemma
valuation_subring.units_mod_principal_units_equiv_residue_field_units_comp_quotient_group_mk
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "quotient_group.mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_mod_principal_units_equiv_residue_field_units_comp_quotient_group_mk_apply (x : A.unit_group) : A.units_mod_principal_units_equiv_residue_field_units.to_monoid_hom (quotient_group.mk x) = A.unit_group_to_residue_field_units x
rfl
lemma
valuation_subring.units_mod_principal_units_equiv_residue_field_units_comp_quotient_group_mk_apply
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "quotient_group.mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pointwise_has_smul : has_smul G (valuation_subring K)
{ smul := λ g S, -- TODO: if we add `valuation_subring.map` at a later date, we should use it here { mem_or_inv_mem' := λ x, (mem_or_inv_mem S (g⁻¹ • x)).imp (subring.mem_pointwise_smul_iff_inv_smul_mem.mpr) (λ h, subring.mem_pointwise_smul_iff_inv_smul_mem.mpr $ by rwa smul_inv''), .. g • S.to_subr...
def
valuation_subring.pointwise_has_smul
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "has_smul", "smul_inv''", "valuation_subring" ]
The action on a valuation subring corresponding to applying the action to every element. This is available as an instance in the `pointwise` locale.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_pointwise_smul (g : G) (S : valuation_subring K) : ↑(g • S) = g • (S : set K)
rfl
lemma
valuation_subring.coe_pointwise_smul
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pointwise_smul_to_subring (g : G) (S : valuation_subring K) : (g • S).to_subring = g • S.to_subring
rfl
lemma
valuation_subring.pointwise_smul_to_subring
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pointwise_mul_action : mul_action G (valuation_subring K)
to_subring_injective.mul_action to_subring pointwise_smul_to_subring
def
valuation_subring.pointwise_mul_action
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "mul_action", "valuation_subring" ]
The action on a valuation subring corresponding to applying the action to every element. This is available as an instance in the `pointwise` locale. This is a stronger version of `valuation_subring.pointwise_has_smul`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_mem_pointwise_smul (g : G) (x : K) (S : valuation_subring K) : x ∈ S → g • x ∈ g • S
(set.smul_mem_smul_set : _ → _ ∈ g • (S : set K))
lemma
valuation_subring.smul_mem_pointwise_smul
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set.smul_mem_smul_set", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_smul_pointwise_iff_exists (g : G) (x : K) (S : valuation_subring K) : x ∈ g • S ↔ ∃ (s : K), s ∈ S ∧ g • s = x
(set.mem_smul_set : x ∈ g • (S : set K) ↔ _)
lemma
valuation_subring.mem_smul_pointwise_iff_exists
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set.mem_smul_set", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pointwise_central_scalar [mul_semiring_action Gᵐᵒᵖ K] [is_central_scalar G K] : is_central_scalar G (valuation_subring K)
⟨λ g S, to_subring_injective $ by exact op_smul_eq_smul g S.to_subring⟩
instance
valuation_subring.pointwise_central_scalar
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "is_central_scalar", "mul_semiring_action", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_mem_pointwise_smul_iff {g : G} {S : valuation_subring K} {x : K} : g • x ∈ g • S ↔ x ∈ S
set.smul_mem_smul_set_iff
lemma
valuation_subring.smul_mem_pointwise_smul_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set.smul_mem_smul_set_iff", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_pointwise_smul_iff_inv_smul_mem {g : G} {S : valuation_subring K} {x : K} : x ∈ g • S ↔ g⁻¹ • x ∈ S
set.mem_smul_set_iff_inv_smul_mem
lemma
valuation_subring.mem_pointwise_smul_iff_inv_smul_mem
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set.mem_smul_set_iff_inv_smul_mem", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_inv_pointwise_smul_iff {g : G} {S : valuation_subring K} {x : K} : x ∈ g⁻¹ • S ↔ g • x ∈ S
set.mem_inv_smul_set_iff
lemma
valuation_subring.mem_inv_pointwise_smul_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set.mem_inv_smul_set_iff", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pointwise_smul_le_pointwise_smul_iff {g : G} {S T : valuation_subring K} : g • S ≤ g • T ↔ S ≤ T
set.set_smul_subset_set_smul_iff
lemma
valuation_subring.pointwise_smul_le_pointwise_smul_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set.set_smul_subset_set_smul_iff", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pointwise_smul_subset_iff {g : G} {S T : valuation_subring K} : g • S ≤ T ↔ S ≤ g⁻¹ • T
set.set_smul_subset_iff
lemma
valuation_subring.pointwise_smul_subset_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set.set_smul_subset_iff", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subset_pointwise_smul_iff {g : G} {S T : valuation_subring K} : S ≤ g • T ↔ g⁻¹ • S ≤ T
set.subset_set_smul_iff
lemma
valuation_subring.subset_pointwise_smul_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "set.subset_set_smul_iff", "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap (A : valuation_subring L) (f : K →+* L) : valuation_subring K
{ mem_or_inv_mem' := λ k, by simp [valuation_subring.mem_or_inv_mem], ..(A.to_subring.comap f) }
def
valuation_subring.comap
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring", "valuation_subring.mem_or_inv_mem" ]
The pullback of a valuation subring `A` along a ring homomorphism `K →+* L`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_comap (A : valuation_subring L) (f : K →+* L) : (A.comap f : set K) = f ⁻¹' A
rfl
lemma
valuation_subring.coe_comap
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_comap {A : valuation_subring L} {f : K →+* L} {x : K} : x ∈ A.comap f ↔ f x ∈ A
iff.rfl
lemma
valuation_subring.mem_comap
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_comap (A : valuation_subring J) (g : L →+* J) (f : K →+* L) : (A.comap g).comap f = A.comap (g.comp f)
rfl
lemma
valuation_subring.comap_comap
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_unit_group_iff : x ∈ v.valuation_subring.unit_group ↔ v x = 1
(valuation.is_equiv_iff_val_eq_one _ _).mp (valuation.is_equiv_valuation_valuation_subring _).symm
lemma
valuation.mem_unit_group_iff
ring_theory.valuation
src/ring_theory/valuation/valuation_subring.lean
[ "ring_theory.valuation.valuation_ring", "ring_theory.localization.as_subring", "ring_theory.subring.pointwise", "algebraic_geometry.prime_spectrum.basic" ]
[ "valuation.is_equiv_iff_val_eq_one", "valuation.is_equiv_valuation_valuation_subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_fun (f : α → β) : 𝕎 α → 𝕎 β
λ x, mk _ (f ∘ x.coeff)
def
witt_vector.map_fun
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
`f : α → β` induces a map from `𝕎 α` to `𝕎 β` by applying `f` componentwise. If `f` is a ring homomorphism, then so is `f`, see `witt_vector.map f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective (f : α → β) (hf : injective f) : injective (map_fun f : 𝕎 α → 𝕎 β)
λ x y h, ext $ λ n, hf (congr_arg (λ x, coeff x n) h : _)
lemma
witt_vector.map_fun.injective
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
surjective (f : α → β) (hf : surjective f) : surjective (map_fun f : 𝕎 α → 𝕎 β)
λ x, ⟨mk _ (λ n, classical.some $ hf $ x.coeff n), by { ext n, dsimp [map_fun], rw classical.some_spec (hf (x.coeff n)) }⟩
lemma
witt_vector.map_fun.surjective
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_fun_tac : tactic unit
`[ext n, show f (aeval _ _) = aeval _ _, rw map_aeval, apply eval₂_hom_congr (ring_hom.ext_int _ _) _ rfl, ext ⟨i, k⟩, fin_cases i; refl]
def
witt_vector.map_fun.map_fun_tac
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "ring_hom.ext_int" ]
Auxiliary tactic for showing that `map_fun` respects the ring operations.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero : map_fun f (0 : 𝕎 R) = 0
by map_fun_tac
lemma
witt_vector.map_fun.zero
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one : map_fun f (1 : 𝕎 R) = 1
by map_fun_tac
lemma
witt_vector.map_fun.one
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add : map_fun f (x + y) = map_fun f x + map_fun f y
by map_fun_tac
lemma
witt_vector.map_fun.add
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub : map_fun f (x - y) = map_fun f x - map_fun f y
by map_fun_tac
lemma
witt_vector.map_fun.sub
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul : map_fun f (x * y) = map_fun f x * map_fun f y
by map_fun_tac
lemma
witt_vector.map_fun.mul
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg : map_fun f (-x) = -map_fun f x
by map_fun_tac
lemma
witt_vector.map_fun.neg
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nsmul (n : ℕ) : map_fun f (n • x) = n • map_fun f x
by map_fun_tac
lemma
witt_vector.map_fun.nsmul
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zsmul (z : ℤ) : map_fun f (z • x) = z • map_fun f x
by map_fun_tac
lemma
witt_vector.map_fun.zsmul
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow (n : ℕ) : map_fun f (x^ n) = map_fun f x ^ n
by map_fun_tac
lemma
witt_vector.map_fun.pow
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_cast (n : ℕ) : map_fun f (n : 𝕎 R) = n
show map_fun f n.unary_cast = coe n, by induction n; simp [*, nat.unary_cast, add, one, zero]; refl
lemma
witt_vector.map_fun.nat_cast
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "nat.unary_cast" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int_cast (n : ℤ) : map_fun f (n : 𝕎 R) = n
show map_fun f n.cast_def = coe n, by cases n; simp [*, int.cast_def, add, one, neg, zero, nat_cast]; refl
lemma
witt_vector.map_fun.int_cast
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "int.cast_def" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tactic.interactive.ghost_fun_tac (φ fn : parse parser.pexpr) : tactic unit
do fn ← to_expr ```(%%fn : fin _ → ℕ → R), `(fin %%k → _ → _) ← infer_type fn, `[ext n], `[dunfold witt_vector.has_zero witt_zero witt_vector.has_one witt_one witt_vector.has_neg witt_neg witt_vector.has_mul witt_mul witt_vector.has_sub witt_sub witt_vector.has_add witt_add witt_vector.has_nat_scalar witt...
def
tactic.interactive.ghost_fun_tac
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "witt_vector.has_int_scalar", "witt_vector.has_nat_pow", "witt_vector.has_nat_scalar" ]
An auxiliary tactic for proving that `ghost_fun` respects the ring operations.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun : 𝕎 R → (ℕ → R)
λ x n, aeval x.coeff (W_ ℤ n)
def
witt_vector.ghost_fun
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
Evaluates the `n`th Witt polynomial on the first `n` coefficients of `x`, producing a value in `R`. This function will be bundled as the ring homomorphism `witt_vector.ghost_map` once the ring structure is available, but we rely on it to set up the ring structure in the first place.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
matrix_vec_empty_coeff {R} (i j) : @coeff p R (matrix.vec_empty i) j = (matrix.vec_empty i : ℕ → R) j
by rcases i with ⟨_ | _ | _ | _ | i_val, ⟨⟩⟩
lemma
witt_vector.matrix_vec_empty_coeff
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "matrix.vec_empty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_zero : ghost_fun (0 : 𝕎 R) = 0
by ghost_fun_tac 0 ![]
lemma
witt_vector.ghost_fun_zero
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_one : ghost_fun (1 : 𝕎 R) = 1
by ghost_fun_tac 1 ![]
lemma
witt_vector.ghost_fun_one
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_add : ghost_fun (x + y) = ghost_fun x + ghost_fun y
by ghost_fun_tac (X 0 + X 1) ![x.coeff, y.coeff]
lemma
witt_vector.ghost_fun_add
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_nat_cast (i : ℕ) : ghost_fun (i : 𝕎 R) = i
show ghost_fun i.unary_cast = _, by induction i; simp [*, nat.unary_cast, ghost_fun_zero, ghost_fun_one, ghost_fun_add, -pi.coe_nat]
lemma
witt_vector.ghost_fun_nat_cast
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "nat.unary_cast", "pi.coe_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_sub : ghost_fun (x - y) = ghost_fun x - ghost_fun y
by ghost_fun_tac (X 0 - X 1) ![x.coeff, y.coeff]
lemma
witt_vector.ghost_fun_sub
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_mul : ghost_fun (x * y) = ghost_fun x * ghost_fun y
by ghost_fun_tac (X 0 * X 1) ![x.coeff, y.coeff]
lemma
witt_vector.ghost_fun_mul
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_neg : ghost_fun (-x) = - ghost_fun x
by ghost_fun_tac (-X 0) ![x.coeff]
lemma
witt_vector.ghost_fun_neg
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_int_cast (i : ℤ) : ghost_fun (i : 𝕎 R) = i
show ghost_fun i.cast_def = _, by cases i; simp [*, int.cast_def, ghost_fun_nat_cast, ghost_fun_neg, -pi.coe_nat, -pi.coe_int]
lemma
witt_vector.ghost_fun_int_cast
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "int.cast_def", "pi.coe_int", "pi.coe_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_nsmul (m : ℕ) : ghost_fun (m • x) = m • ghost_fun x
by ghost_fun_tac (m • X 0) ![x.coeff]
lemma
witt_vector.ghost_fun_nsmul
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_zsmul (m : ℤ) : ghost_fun (m • x) = m • ghost_fun x
by ghost_fun_tac (m • X 0) ![x.coeff]
lemma
witt_vector.ghost_fun_zsmul
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_fun_pow (m : ℕ) : ghost_fun (x ^ m) = ghost_fun x ^ m
by ghost_fun_tac (X 0 ^ m) ![x.coeff]
lemma
witt_vector.ghost_fun_pow
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_equiv' [invertible (p : R)] : 𝕎 R ≃ (ℕ → R)
{ to_fun := ghost_fun, inv_fun := λ x, mk p $ λ n, aeval x (X_in_terms_of_W p R n), left_inv := begin intro x, ext n, have := bind₁_witt_polynomial_X_in_terms_of_W p R n, apply_fun (aeval x.coeff) at this, simpa only [aeval_bind₁, aeval_X, ghost_fun, aeval_witt_polynomial] end, right_inv :...
def
witt_vector.ghost_equiv'
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "X_in_terms_of_W", "aeval_witt_polynomial", "bind₁_X_in_terms_of_W_witt_polynomial", "bind₁_witt_polynomial_X_in_terms_of_W", "inv_fun", "invertible" ]
The bijection between `𝕎 R` and `ℕ → R`, under the assumption that `p` is invertible in `R`. In `witt_vector.ghost_equiv` we upgrade this to an isomorphism of rings.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comm_ring_aux₁ : comm_ring (𝕎 (mv_polynomial R ℚ))
by letI : comm_ring (mv_polynomial R ℚ) := mv_polynomial.comm_ring; exact (ghost_equiv' p (mv_polynomial R ℚ)).injective.comm_ring (ghost_fun) ghost_fun_zero ghost_fun_one ghost_fun_add ghost_fun_mul ghost_fun_neg ghost_fun_sub ghost_fun_nsmul ghost_fun_zsmul ghost_fun_pow ghost_fun_nat_cast ghost_fun_int_cast
def
witt_vector.comm_ring_aux₁
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "comm_ring", "mv_polynomial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comm_ring_aux₂ : comm_ring (𝕎 (mv_polynomial R ℤ))
(map_fun.injective _ $ map_injective (int.cast_ring_hom ℚ) int.cast_injective).comm_ring _ (map_fun.zero _) (map_fun.one _) (map_fun.add _) (map_fun.mul _) (map_fun.neg _) (map_fun.sub _) (map_fun.nsmul _) (map_fun.zsmul _) (map_fun.pow _) (map_fun.nat_cast _) (map_fun.int_cast _)
def
witt_vector.comm_ring_aux₂
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "comm_ring", "int.cast_injective", "int.cast_ring_hom", "mv_polynomial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_injective (f : R →+* S) (hf : injective f) : injective (map f : 𝕎 R → 𝕎 S)
map_fun.injective f hf
lemma
witt_vector.map_injective
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_surjective (f : R →+* S) (hf : surjective f) : surjective (map f : 𝕎 R → 𝕎 S)
map_fun.surjective f hf
lemma
witt_vector.map_surjective
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_coeff (f : R →+* S) (x : 𝕎 R) (n : ℕ) : (map f x).coeff n = f (x.coeff n)
rfl
lemma
witt_vector.map_coeff
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_map : 𝕎 R →+* ℕ → R
{ to_fun := ghost_fun, map_zero' := ghost_fun_zero, map_one' := ghost_fun_one, map_add' := ghost_fun_add, map_mul' := ghost_fun_mul }
def
witt_vector.ghost_map
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
`witt_vector.ghost_map` is a ring homomorphism that maps each Witt vector to the sequence of its ghost components.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_component (n : ℕ) : 𝕎 R →+* R
(pi.eval_ring_hom _ n).comp ghost_map
def
witt_vector.ghost_component
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[ "pi.eval_ring_hom" ]
Evaluates the `n`th Witt polynomial on the first `n` coefficients of `x`, producing a value in `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_component_apply (n : ℕ) (x : 𝕎 R) : ghost_component n x = aeval x.coeff (W_ ℤ n)
rfl
lemma
witt_vector.ghost_component_apply
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_map_apply (x : 𝕎 R) (n : ℕ) : ghost_map x n = ghost_component n x
rfl
lemma
witt_vector.ghost_map_apply
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_equiv : 𝕎 R ≃+* (ℕ → R)
{ .. (ghost_map : 𝕎 R →+* (ℕ → R)), .. (ghost_equiv' p R) }
def
witt_vector.ghost_equiv
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
`witt_vector.ghost_map` is a ring isomorphism when `p` is invertible in `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_equiv_coe : (ghost_equiv p R : 𝕎 R →+* (ℕ → R)) = ghost_map
rfl
lemma
witt_vector.ghost_equiv_coe
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ghost_map.bijective_of_invertible : function.bijective (ghost_map : 𝕎 R → ℕ → R)
(ghost_equiv p R).bijective
lemma
witt_vector.ghost_map.bijective_of_invertible
ring_theory.witt_vector
src/ring_theory/witt_vector/basic.lean
[ "data.mv_polynomial.counit", "data.mv_polynomial.invertible", "ring_theory.witt_vector.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_of_le_of_cast_pow_eq_zero [char_p R p] (i : ℕ) (hin : i ≤ n) (hpi : (p ^ i : truncated_witt_vector p n R) = 0) : i = n
begin contrapose! hpi, replace hin := lt_of_le_of_ne hin hpi, clear hpi, have : (↑p ^ i : truncated_witt_vector p n R) = witt_vector.truncate n (↑p ^ i), { rw [ring_hom.map_pow, map_nat_cast] }, rw [this, ext_iff, not_forall], clear this, use ⟨i, hin⟩, rw [witt_vector.coeff_truncate, coeff_zero, fin.coe_m...
lemma
truncated_witt_vector.eq_of_le_of_cast_pow_eq_zero
ring_theory.witt_vector
src/ring_theory/witt_vector/compare.lean
[ "ring_theory.witt_vector.truncated", "ring_theory.witt_vector.identities", "number_theory.padics.ring_homs" ]
[ "char_p", "char_p.nontrivial_of_char_ne_one", "fin.coe_mk", "map_nat_cast", "nontrivial", "not_forall", "one_ne_zero", "ring_hom.map_pow", "truncated_witt_vector", "witt_vector.coeff_p_pow", "witt_vector.coeff_truncate" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_zmod : fintype.card (truncated_witt_vector p n (zmod p)) = p ^ n
by rw [card, zmod.card]
lemma
truncated_witt_vector.card_zmod
ring_theory.witt_vector
src/ring_theory/witt_vector/compare.lean
[ "ring_theory.witt_vector.truncated", "ring_theory.witt_vector.identities", "number_theory.padics.ring_homs" ]
[ "fintype.card", "truncated_witt_vector", "zmod", "zmod.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
char_p_zmod : char_p (truncated_witt_vector p n (zmod p)) (p ^ n)
char_p_of_prime_pow_injective _ _ _ (card_zmod _ _) (eq_of_le_of_cast_pow_eq_zero p n (zmod p))
lemma
truncated_witt_vector.char_p_zmod
ring_theory.witt_vector
src/ring_theory/witt_vector/compare.lean
[ "ring_theory.witt_vector.truncated", "ring_theory.witt_vector.identities", "number_theory.padics.ring_homs" ]
[ "char_p", "char_p_of_prime_pow_injective", "truncated_witt_vector", "zmod" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zmod_equiv_trunc : zmod (p^n) ≃+* truncated_witt_vector p n (zmod p)
zmod.ring_equiv (truncated_witt_vector p n (zmod p)) (card_zmod _ _)
def
truncated_witt_vector.zmod_equiv_trunc
ring_theory.witt_vector
src/ring_theory/witt_vector/compare.lean
[ "ring_theory.witt_vector.truncated", "ring_theory.witt_vector.identities", "number_theory.padics.ring_homs" ]
[ "truncated_witt_vector", "zmod", "zmod.ring_equiv" ]
The unique isomorphism between `zmod p^n` and `truncated_witt_vector p n (zmod p)`. This isomorphism exists, because `truncated_witt_vector p n (zmod p)` is a finite ring with characteristic and cardinality `p^n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83