statement
stringlengths
1
2.88k
proof
stringlengths
0
13.9k
type
stringclasses
10 values
symbolic_name
stringlengths
1
131
library
stringclasses
417 values
filename
stringlengths
17
80
imports
listlengths
0
16
deps
listlengths
0
64
docstring
stringlengths
0
10.2k
source_url
stringclasses
1 value
commit
stringclasses
1 value
coe_copy (f : α →+* β) (f' : α → β) (h : f' = f) : ⇑(f.copy f' h) = f'
rfl
lemma
ring_hom.coe_copy
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
copy_eq (f : α →+* β) (f' : α → β) (h : f' = f) : f.copy f' h = f
fun_like.ext' h
lemma
ring_hom.copy_eq
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "fun_like.ext'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
congr_fun {f g : α →+* β} (h : f = g) (x : α) : f x = g x
fun_like.congr_fun h x
lemma
ring_hom.congr_fun
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "fun_like.congr_fun" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
congr_arg (f : α →+* β) {x y : α} (h : x = y) : f x = f y
fun_like.congr_arg f h
lemma
ring_hom.congr_arg
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "fun_like.congr_arg" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_inj ⦃f g : α →+* β⦄ (h : (f : α → β) = g) : f = g
fun_like.coe_injective h
lemma
ring_hom.coe_inj
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "fun_like.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext ⦃f g : α →+* β⦄ : (∀ x, f x = g x) → f = g
fun_like.ext _ _
lemma
ring_hom.ext
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "fun_like.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext_iff {f g : α →+* β} : f = g ↔ ∀ x, f x = g x
fun_like.ext_iff
lemma
ring_hom.ext_iff
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "fun_like.ext_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_coe (f : α →+* β) (h₁ h₂ h₃ h₄) : ring_hom.mk f h₁ h₂ h₃ h₄ = f
ext $ λ _, rfl
lemma
ring_hom.mk_coe
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_add_monoid_hom_injective : injective (coe : (α →+* β) → (α →+ β))
λ f g h, ext $ add_monoid_hom.congr_fun h
lemma
ring_hom.coe_add_monoid_hom_injective
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_monoid_hom_injective : injective (coe : (α →+* β) → (α →* β))
λ f g h, ext $ monoid_hom.congr_fun h
lemma
ring_hom.coe_monoid_hom_injective
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "monoid_hom.congr_fun" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_zero (f : α →+* β) : f 0 = 0
map_zero f
lemma
ring_hom.map_zero
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
Ring homomorphisms map zero to zero.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_one (f : α →+* β) : f 1 = 1
map_one f
lemma
ring_hom.map_one
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "map_one" ]
Ring homomorphisms map one to one.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_add (f : α →+* β) : ∀ a b, f (a + b) = f a + f b
map_add f
lemma
ring_hom.map_add
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
Ring homomorphisms preserve addition.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mul (f : α →+* β) : ∀ a b, f (a * b) = f a * f b
map_mul f
lemma
ring_hom.map_mul
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "map_mul" ]
Ring homomorphisms preserve multiplication.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_bit0 (f : α →+* β) : ∀ a, f (bit0 a) = bit0 (f a)
map_bit0 f
lemma
ring_hom.map_bit0
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "map_bit0" ]
Ring homomorphisms preserve `bit0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_bit1 (f : α →+* β) : ∀ a, f (bit1 a) = bit1 (f a)
map_bit1 f
lemma
ring_hom.map_bit1
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "map_bit1" ]
Ring homomorphisms preserve `bit1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_ite_zero_one {F : Type*} [ring_hom_class F α β] (f : F) (p : Prop) [decidable p] : f (ite p 0 1) = ite p 0 1
by { split_ifs; simp [h] }
lemma
ring_hom.map_ite_zero_one
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "ring_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_ite_one_zero {F : Type*} [ring_hom_class F α β] (f : F) (p : Prop) [decidable p] : f (ite p 1 0) = ite p 1 0
by { split_ifs; simp [h] }
lemma
ring_hom.map_ite_one_zero
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "ring_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
codomain_trivial_iff_map_one_eq_zero : (0 : β) = 1 ↔ f 1 = 0
by rw [map_one, eq_comm]
lemma
ring_hom.codomain_trivial_iff_map_one_eq_zero
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "map_one" ]
`f : α →+* β` has a trivial codomain iff `f 1 = 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
codomain_trivial_iff_range_trivial : (0 : β) = 1 ↔ ∀ x, f x = 0
f.codomain_trivial_iff_map_one_eq_zero.trans ⟨λ h x, by rw [←mul_one x, map_mul, h, mul_zero], λ h, h 1⟩
lemma
ring_hom.codomain_trivial_iff_range_trivial
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "map_mul", "mul_zero" ]
`f : α →+* β` has a trivial codomain iff it has a trivial range.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
codomain_trivial_iff_range_eq_singleton_zero : (0 : β) = 1 ↔ set.range f = {0}
f.codomain_trivial_iff_range_trivial.trans ⟨ λ h, set.ext (λ y, ⟨λ ⟨x, hx⟩, by simp [←hx, h x], λ hy, ⟨0, by simpa using hy.symm⟩⟩), λ h x, set.mem_singleton_iff.mp (h ▸ set.mem_range_self x)⟩
lemma
ring_hom.codomain_trivial_iff_range_eq_singleton_zero
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "set.ext", "set.mem_range_self", "set.range" ]
`f : α →+* β` has a trivial codomain iff its range is `{0}`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_one_ne_zero [nontrivial β] : f 1 ≠ 0
mt f.codomain_trivial_iff_map_one_eq_zero.mpr zero_ne_one
lemma
ring_hom.map_one_ne_zero
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "nontrivial", "zero_ne_one" ]
`f : α →+* β` doesn't map `1` to `0` if `β` is nontrivial
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
domain_nontrivial [nontrivial β] : nontrivial α
⟨⟨1, 0, mt (λ h, show f 1 = 0, by rw [h, map_zero]) f.map_one_ne_zero⟩⟩
lemma
ring_hom.domain_nontrivial
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "nontrivial" ]
If there is a homomorphism `f : α →+* β` and `β` is nontrivial, then `α` is nontrivial.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
codomain_trivial (f : α →+* β) [h : subsingleton α] : subsingleton β
(subsingleton_or_nontrivial β).resolve_right (λ _, by exactI not_nontrivial_iff_subsingleton.mpr h f.domain_nontrivial)
lemma
ring_hom.codomain_trivial
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "subsingleton_or_nontrivial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_neg [non_assoc_ring α] [non_assoc_ring β] (f : α →+* β) (x : α) : f (-x) = -(f x)
map_neg f x
theorem
ring_hom.map_neg
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "non_assoc_ring" ]
Ring homomorphisms preserve additive inverse.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_sub [non_assoc_ring α] [non_assoc_ring β] (f : α →+* β) (x y : α) : f (x - y) = (f x) - (f y)
map_sub f x y
theorem
ring_hom.map_sub
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "non_assoc_ring" ]
Ring homomorphisms preserve subtraction.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk' [non_assoc_semiring α] [non_assoc_ring β] (f : α →* β) (map_add : ∀ a b, f (a + b) = f a + f b) : α →+* β
{ ..add_monoid_hom.mk' f map_add, ..f }
def
ring_hom.mk'
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "mk'", "non_assoc_ring", "non_assoc_semiring" ]
Makes a ring homomorphism from a monoid homomorphism of rings which preserves addition.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit_map (f : α →+* β) {a : α} : is_unit a → is_unit (f a)
is_unit.map f
lemma
ring_hom.is_unit_map
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "is_unit", "is_unit.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_dvd (f : α →+* β) {a b : α} : a ∣ b → f a ∣ f b
map_dvd f
lemma
ring_hom.map_dvd
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "map_dvd" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id (α : Type*) [non_assoc_semiring α] : α →+* α
by refine {to_fun := id, ..}; intros; refl
def
ring_hom.id
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "non_assoc_semiring" ]
The identity ring homomorphism from a semiring to itself.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id_apply (x : α) : ring_hom.id α x = x
rfl
lemma
ring_hom.id_apply
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "ring_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_add_monoid_hom_id : (id α : α →+ α) = add_monoid_hom.id α
rfl
lemma
ring_hom.coe_add_monoid_hom_id
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_monoid_hom_id : (id α : α →* α) = monoid_hom.id α
rfl
lemma
ring_hom.coe_monoid_hom_id
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "monoid_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp (g : β →+* γ) (f : α →+* β) : α →+* γ
{ to_fun := g ∘ f, map_one' := by simp, ..g.to_non_unital_ring_hom.comp f.to_non_unital_ring_hom }
def
ring_hom.comp
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
Composition of ring homomorphisms is a ring homomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_assoc {δ} {rδ: non_assoc_semiring δ} (f : α →+* β) (g : β →+* γ) (h : γ →+* δ) : (h.comp g).comp f = h.comp (g.comp f)
rfl
lemma
ring_hom.comp_assoc
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "non_assoc_semiring" ]
Composition of semiring homomorphisms is associative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_comp (hnp : β →+* γ) (hmn : α →+* β) : (hnp.comp hmn : α → γ) = hnp ∘ hmn
rfl
lemma
ring_hom.coe_comp
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_apply (hnp : β →+* γ) (hmn : α →+* β) (x : α) : (hnp.comp hmn : α → γ) x = (hnp (hmn x))
rfl
lemma
ring_hom.comp_apply
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_id (f : α →+* β) : f.comp (id α) = f
ext $ λ x, rfl
lemma
ring_hom.comp_id
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id_comp (f : α →+* β) : (id β).comp f = f
ext $ λ x, rfl
lemma
ring_hom.id_comp
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_def : (1 : α →+* α) = id α
rfl
lemma
ring_hom.one_def
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_def (f g : α →+* α) : f * g = f.comp g
rfl
lemma
ring_hom.mul_def
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_one : ⇑(1 : α →+* α) = _root_.id
rfl
lemma
ring_hom.coe_one
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul (f g : α →+* α) : ⇑(f * g) = f ∘ g
rfl
lemma
ring_hom.coe_mul
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cancel_right {g₁ g₂ : β →+* γ} {f : α →+* β} (hf : surjective f) : g₁.comp f = g₂.comp f ↔ g₁ = g₂
⟨λ h, ring_hom.ext $ hf.forall.2 (ext_iff.1 h), λ h, h ▸ rfl⟩
lemma
ring_hom.cancel_right
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "ring_hom.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cancel_left {g : β →+* γ} {f₁ f₂ : α →+* β} (hg : injective g) : g.comp f₁ = g.comp f₂ ↔ f₁ = f₂
⟨λ h, ring_hom.ext $ λ x, hg $ by rw [← comp_apply, h, comp_apply], λ h, h ▸ rfl⟩
lemma
ring_hom.cancel_left
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "ring_hom.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
function.injective.is_domain [ring α] [is_domain α] [ring β] (f : β →+* α) (hf : injective f) : is_domain β
begin haveI := pullback_nonzero f f.map_zero f.map_one, haveI := is_right_cancel_mul_zero.to_no_zero_divisors α, haveI := hf.no_zero_divisors f f.map_zero f.map_mul, exact no_zero_divisors.to_is_domain β, end
theorem
function.injective.is_domain
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "is_domain", "is_right_cancel_mul_zero.to_no_zero_divisors", "no_zero_divisors.to_is_domain", "pullback_nonzero", "ring" ]
Pullback `is_domain` instance along an injective function.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_ring_hom_of_mul_self_of_two_ne_zero (h : ∀ x, f (x * x) = f x * f x) (h_two : (2 : α) ≠ 0) (h_one : f 1 = 1) : β →+* α
{ map_one' := h_one, map_mul' := λ x y, begin have hxy := h (x + y), rw [mul_add, add_mul, add_mul, f.map_add, f.map_add, f.map_add, f.map_add, h x, h y, add_mul, mul_add, mul_add, ← sub_eq_zero, add_comm, ← sub_sub, ← sub_sub, ← sub_sub, mul_comm y x, mul_comm (f y) (f x)] at hxy, simp only [...
def
add_monoid_hom.mk_ring_hom_of_mul_self_of_two_ne_zero
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[ "mul_comm", "mul_eq_zero", "or_iff_not_imp_left", "two_mul" ]
Make a ring homomorphism from an additive group homomorphism from a commutative ring to an integral domain that commutes with self multiplication, assumes that two is nonzero and `1` is sent to `1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_fn_mk_ring_hom_of_mul_self_of_two_ne_zero (h h_two h_one) : (f.mk_ring_hom_of_mul_self_of_two_ne_zero h h_two h_one : β → α) = f
rfl
lemma
add_monoid_hom.coe_fn_mk_ring_hom_of_mul_self_of_two_ne_zero
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_add_monoid_hom_mk_ring_hom_of_mul_self_of_two_ne_zero (h h_two h_one) : (f.mk_ring_hom_of_mul_self_of_two_ne_zero h h_two h_one : β →+ α) = f
by { ext, refl }
lemma
add_monoid_hom.coe_add_monoid_hom_mk_ring_hom_of_mul_self_of_two_ne_zero
algebra.hom
src/algebra/hom/ring.lean
[ "algebra.group_with_zero.inj_surj", "algebra.ring.basic", "algebra.divisibility.basic", "data.pi.algebra", "algebra.hom.units", "data.set.image" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
group.is_unit {G} [group G] (g : G) : is_unit g
⟨⟨g, g⁻¹, mul_inv_self g, inv_mul_self g⟩, rfl⟩
lemma
group.is_unit
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "group", "inv_mul_self", "is_unit", "mul_inv_self" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit.eq_on_inv {F G N} [division_monoid G] [monoid N] [monoid_hom_class F G N] {x : G} (hx : is_unit x) (f g : F) (h : f x = g x) : f x⁻¹ = g x⁻¹
left_inv_eq_right_inv (map_mul_eq_one f hx.inv_mul_cancel) $ h.symm ▸ map_mul_eq_one g $ hx.mul_inv_cancel
lemma
is_unit.eq_on_inv
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "division_monoid", "is_unit", "left_inv_eq_right_inv", "map_mul_eq_one", "monoid", "monoid_hom_class" ]
If two homomorphisms from a division monoid to a monoid are equal at a unit `x`, then they are equal at `x⁻¹`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_on_inv {F G M} [group G] [monoid M] [monoid_hom_class F G M] (f g : F) {x : G} (h : f x = g x) : f x⁻¹ = g x⁻¹
(group.is_unit x).eq_on_inv f g h
lemma
eq_on_inv
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "group", "group.is_unit", "monoid", "monoid_hom_class" ]
If two homomorphism from a group to a monoid are equal at `x`, then they are equal at `x⁻¹`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map (f : M →* N) : Mˣ →* Nˣ
monoid_hom.mk' (λ u, ⟨f u.val, f u.inv, by rw [← f.map_mul, u.val_inv, f.map_one], by rw [← f.map_mul, u.inv_val, f.map_one]⟩) (λ x y, ext (f.map_mul x y))
def
units.map
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "monoid_hom.mk'" ]
The group homomorphism on units induced by a `monoid_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_map (f : M →* N) (x : Mˣ) : ↑(map f x) = f x
rfl
lemma
units.coe_map
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_map_inv (f : M →* N) (u : Mˣ) : ↑(map f u)⁻¹ = f ↑u⁻¹
rfl
lemma
units.coe_map_inv
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_comp (f : M →* N) (g : N →* P) : map (g.comp f) = (map g).comp (map f)
rfl
lemma
units.map_comp
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "map_comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_id : map (monoid_hom.id M) = monoid_hom.id Mˣ
by ext; refl
lemma
units.map_id
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "map_id", "monoid_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_hom : Mˣ →* M
⟨coe, coe_one, coe_mul⟩
def
units.coe_hom
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[]
Coercion `Mˣ → M` as a monoid homomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_hom_apply (x : Mˣ) : coe_hom M x = ↑x
rfl
lemma
units.coe_hom_apply
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_pow (u : Mˣ) (n : ℕ) : ((u ^ n : Mˣ) : M) = u ^ n
(units.coe_hom M).map_pow u n
lemma
units.coe_pow
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "map_pow", "units.coe_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_div : ∀ u₁ u₂ : αˣ, ↑(u₁ / u₂) = (u₁ / u₂ : α)
(units.coe_hom α).map_div
lemma
units.coe_div
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "map_div", "units.coe_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_zpow : ∀ (u : αˣ) (n : ℤ), ((u ^ n : αˣ) : α) = u ^ n
(units.coe_hom α).map_zpow
lemma
units.coe_zpow
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "map_zpow", "units.coe_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.divp_eq_div (a : α) (u : αˣ) : a /ₚ u = a / u
by rw [div_eq_mul_inv, divp, u.coe_inv]
lemma
divp_eq_div
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "div_eq_mul_inv", "divp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.map_units_inv {F : Type*} [monoid_hom_class F M α] (f : F) (u : units M) : f ↑u⁻¹ = (f u)⁻¹
((f : M →* α).comp (units.coe_hom M)).map_inv u
lemma
map_units_inv
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "map_inv", "monoid_hom_class", "units", "units.coe_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_right (f : M →* N) (g : M → Nˣ) (h : ∀ x, ↑(g x) = f x) : M →* Nˣ
{ to_fun := g, map_one' := units.ext $ (h 1).symm ▸ f.map_one, map_mul' := λ x y, units.ext $ by simp only [h, coe_mul, f.map_mul] }
def
units.lift_right
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "units.ext" ]
If a map `g : M → Nˣ` agrees with a homomorphism `f : M →* N`, then this map is a monoid homomorphism too.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_lift_right {f : M →* N} {g : M → Nˣ} (h : ∀ x, ↑(g x) = f x) (x) : (lift_right f g h x : N) = f x
h x
lemma
units.coe_lift_right
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_lift_right_inv {f : M →* N} {g : M → Nˣ} (h : ∀ x, ↑(g x) = f x) (x) : f x * ↑(lift_right f g h x)⁻¹ = 1
by rw [units.mul_inv_eq_iff_eq_mul, one_mul, coe_lift_right]
lemma
units.mul_lift_right_inv
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "one_mul", "units.mul_inv_eq_iff_eq_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_right_inv_mul {f : M →* N} {g : M → Nˣ} (h : ∀ x, ↑(g x) = f x) (x) : ↑(lift_right f g h x)⁻¹ * f x = 1
by rw [units.inv_mul_eq_iff_eq_mul, mul_one, coe_lift_right]
lemma
units.lift_right_inv_mul
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "mul_one", "units.inv_mul_eq_iff_eq_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_hom_units {G M : Type*} [group G] [monoid M] (f : G →* M) : G →* Mˣ
units.lift_right f (λ g, ⟨f g, f g⁻¹, map_mul_eq_one f (mul_inv_self _), map_mul_eq_one f (inv_mul_self _)⟩) (λ g, rfl)
def
monoid_hom.to_hom_units
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "group", "inv_mul_self", "map_mul_eq_one", "monoid", "mul_inv_self", "units.lift_right" ]
If `f` is a homomorphism from a group `G` to a monoid `M`, then its image lies in the units of `M`, and `f.to_hom_units` is the corresponding monoid homomorphism from `G` to `Mˣ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_to_hom_units {G M : Type*} [group G] [monoid M] (f : G →* M) (g : G) : (f.to_hom_units g : M) = f g
rfl
lemma
monoid_hom.coe_to_hom_units
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "group", "monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map [monoid_hom_class F M N] (f : F) {x : M} (h : is_unit x) : is_unit (f x)
by rcases h with ⟨y, rfl⟩; exact (units.map (f : M →* N) y).is_unit
lemma
is_unit.map
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "monoid_hom_class", "units.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_left_inverse [monoid_hom_class F M N] [monoid_hom_class G N M] {f : F} {x : M} (g : G) (hfg : function.left_inverse g f) (h : is_unit (f x)) : is_unit x
by simpa only [hfg x] using h.map g
lemma
is_unit.of_left_inverse
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "monoid_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.is_unit_map_of_left_inverse [monoid_hom_class F M N] [monoid_hom_class G N M] {f : F} {x : M} (g : G) (hfg : function.left_inverse g f) : is_unit (f x) ↔ is_unit x
⟨of_left_inverse g hfg, map _⟩
lemma
is_unit_map_of_left_inverse
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "monoid_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_right (f : M →* N) (hf : ∀ x, is_unit (f x)) : M →* Nˣ
units.lift_right f (λ x, (hf x).unit) $ λ x, rfl
def
is_unit.lift_right
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "units.lift_right" ]
If a homomorphism `f : M →* N` sends each element to an `is_unit`, then it can be lifted to `f : M →* Nˣ`. See also `units.lift_right` for a computable version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_lift_right (f : M →* N) (hf : ∀ x, is_unit (f x)) (x) : (is_unit.lift_right f hf x : N) = f x
rfl
lemma
is_unit.coe_lift_right
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "is_unit.lift_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_lift_right_inv (f : M →* N) (h : ∀ x, is_unit (f x)) (x) : f x * ↑(is_unit.lift_right f h x)⁻¹ = 1
units.mul_lift_right_inv (λ y, rfl) x
lemma
is_unit.mul_lift_right_inv
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "is_unit.lift_right", "units.mul_lift_right_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_right_inv_mul (f : M →* N) (h : ∀ x, is_unit (f x)) (x) : ↑(is_unit.lift_right f h x)⁻¹ * f x = 1
units.lift_right_inv_mul (λ y, rfl) x
lemma
is_unit.lift_right_inv_mul
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "is_unit.lift_right", "units.lift_right_inv_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit' (h : is_unit a) : αˣ
⟨a, a⁻¹, h.mul_inv_cancel, h.inv_mul_cancel⟩
def
is_unit.unit'
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit" ]
The element of the group of units, corresponding to an element of a monoid which is a unit. As opposed to `is_unit.unit`, the inverse is computable and comes from the inversion on `α`. This is useful to transfer properties of inversion in `units α` to `α`. See also `to_units`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_cancel_left (h : is_unit a) : ∀ b, a * (a⁻¹ * b) = b
h.unit'.mul_inv_cancel_left
lemma
is_unit.mul_inv_cancel_left
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "mul_inv_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_mul_cancel_left (h : is_unit a) : ∀ b, a⁻¹ * (a * b) = b
h.unit'.inv_mul_cancel_left
lemma
is_unit.inv_mul_cancel_left
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "inv_mul_cancel_left", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_cancel_right (h : is_unit b) (a : α) : a * b * b⁻¹ = a
h.unit'.mul_inv_cancel_right _
lemma
is_unit.mul_inv_cancel_right
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "mul_inv_cancel_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_mul_cancel_right (h : is_unit b) (a : α) : a * b⁻¹ * b = a
h.unit'.inv_mul_cancel_right _
lemma
is_unit.inv_mul_cancel_right
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "inv_mul_cancel_right", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_self (h : is_unit a) : a / a = 1
by rw [div_eq_mul_inv, h.mul_inv_cancel]
lemma
is_unit.div_self
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "div_eq_mul_inv", "div_self", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_mul_inv_iff_mul_eq (h : is_unit c) : a = b * c⁻¹ ↔ a * c = b
h.unit'.eq_mul_inv_iff_mul_eq
lemma
is_unit.eq_mul_inv_iff_mul_eq
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "eq_mul_inv_iff_mul_eq", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_inv_mul_iff_mul_eq (h : is_unit b) : a = b⁻¹ * c ↔ b * a = c
h.unit'.eq_inv_mul_iff_mul_eq
lemma
is_unit.eq_inv_mul_iff_mul_eq
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "eq_inv_mul_iff_mul_eq", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_mul_eq_iff_eq_mul (h : is_unit a) : a⁻¹ * b = c ↔ b = a * c
h.unit'.inv_mul_eq_iff_eq_mul
lemma
is_unit.inv_mul_eq_iff_eq_mul
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "inv_mul_eq_iff_eq_mul", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_eq_iff_eq_mul (h : is_unit b) : a * b⁻¹ = c ↔ a = c * b
h.unit'.mul_inv_eq_iff_eq_mul
lemma
is_unit.mul_inv_eq_iff_eq_mul
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "mul_inv_eq_iff_eq_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_eq_one (h : is_unit b) : a * b⁻¹ = 1 ↔ a = b
@units.mul_inv_eq_one _ _ h.unit' _
lemma
is_unit.mul_inv_eq_one
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "mul_inv_eq_one", "units.mul_inv_eq_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_mul_eq_one (h : is_unit a) : a⁻¹ * b = 1 ↔ a = b
@units.inv_mul_eq_one _ _ h.unit' _
lemma
is_unit.inv_mul_eq_one
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "inv_mul_eq_one", "is_unit", "units.inv_mul_eq_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_eq_one_iff_eq_inv (h : is_unit b) : a * b = 1 ↔ a = b⁻¹
@units.mul_eq_one_iff_eq_inv _ _ h.unit' _
lemma
is_unit.mul_eq_one_iff_eq_inv
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "mul_eq_one_iff_eq_inv", "units.mul_eq_one_iff_eq_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_eq_one_iff_inv_eq (h : is_unit a) : a * b = 1 ↔ a⁻¹ = b
@units.mul_eq_one_iff_inv_eq _ _ h.unit' _
lemma
is_unit.mul_eq_one_iff_inv_eq
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "mul_eq_one_iff_inv_eq", "units.mul_eq_one_iff_inv_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_mul_cancel (h : is_unit b) (a : α) : a / b * b = a
by rw [div_eq_mul_inv, h.inv_mul_cancel_right]
lemma
is_unit.div_mul_cancel
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "div_eq_mul_inv", "div_mul_cancel", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_div_cancel (h : is_unit b) (a : α) : a * b / b = a
by rw [div_eq_mul_inv, h.mul_inv_cancel_right]
lemma
is_unit.mul_div_cancel
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "div_eq_mul_inv", "is_unit", "mul_div_cancel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_one_div_cancel (h : is_unit a) : a * (1 / a) = 1
by simp [h]
lemma
is_unit.mul_one_div_cancel
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "mul_one_div_cancel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_div_mul_cancel (h : is_unit a) : (1 / a) * a = 1
by simp [h]
lemma
is_unit.one_div_mul_cancel
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "one_div_mul_cancel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv : is_unit a → is_unit a⁻¹
by { rintro ⟨u, rfl⟩, rw ←units.coe_inv, exact units.is_unit _ }
lemma
is_unit.inv
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "is_unit", "units.is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div (ha : is_unit a) (hb : is_unit b) : is_unit (a / b)
by { rw div_eq_mul_inv, exact ha.mul hb.inv }
lemma
is_unit.div
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "div_eq_mul_inv", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_left_inj (h : is_unit c) : a / c = b / c ↔ a = b
by { simp_rw div_eq_mul_inv, exact units.mul_left_inj h.inv.unit' }
lemma
is_unit.div_left_inj
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "div_eq_mul_inv", "div_left_inj", "is_unit", "units.mul_left_inj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_iff (h : is_unit b) : a / b = c ↔ a = c * b
by rw [div_eq_mul_inv, h.mul_inv_eq_iff_eq_mul]
lemma
is_unit.div_eq_iff
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "div_eq_iff", "div_eq_mul_inv", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_div_iff (h : is_unit c) : a = b / c ↔ a * c = b
by rw [div_eq_mul_inv, h.eq_mul_inv_iff_mul_eq]
lemma
is_unit.eq_div_iff
algebra.hom
src/algebra/hom/units.lean
[ "algebra.hom.group", "algebra.group.units" ]
[ "div_eq_mul_inv", "eq_div_iff", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83