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coe_id : ⇑(centroid_hom.id α) = id
rfl
lemma
centroid_hom.coe_id
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_to_add_monoid_hom_id : (centroid_hom.id α : α →+ α) = add_monoid_hom.id α
rfl
lemma
centroid_hom.coe_to_add_monoid_hom_id
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id_apply (a : α) : centroid_hom.id α a = a
rfl
lemma
centroid_hom.id_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp (g f : centroid_hom α) : centroid_hom α
{ map_mul_left' := λ a b, (congr_arg g $ f.map_mul_left' _ _).trans $ g.map_mul_left' _ _, map_mul_right' := λ a b, (congr_arg g $ f.map_mul_right' _ _).trans $ g.map_mul_right' _ _, .. g.to_add_monoid_hom.comp f.to_add_monoid_hom }
def
centroid_hom.comp
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
Composition of `centroid_hom`s as a `centroid_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_comp (g f : centroid_hom α) : ⇑(g.comp f) = g ∘ f
rfl
lemma
centroid_hom.coe_comp
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_apply (g f : centroid_hom α) (a : α) : g.comp f a = g (f a)
rfl
lemma
centroid_hom.comp_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_comp_add_monoid_hom (g f : centroid_hom α) : (g.comp f : α →+ α) = (g : α →+ α).comp f
rfl
lemma
centroid_hom.coe_comp_add_monoid_hom
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_assoc (h g f : centroid_hom α) : (h.comp g).comp f = h.comp (g.comp f)
rfl
lemma
centroid_hom.comp_assoc
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_id (f : centroid_hom α) : f.comp (centroid_hom.id α) = f
ext $ λ a, rfl
lemma
centroid_hom.comp_id
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom", "centroid_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id_comp (f : centroid_hom α) : (centroid_hom.id α).comp f = f
ext $ λ a, rfl
lemma
centroid_hom.id_comp
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom", "centroid_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cancel_right {g₁ g₂ f : centroid_hom α} (hf : surjective f) : g₁.comp f = g₂.comp f ↔ g₁ = g₂
⟨λ h, ext $ hf.forall.2 $ fun_like.ext_iff.1 h, congr_arg _⟩
lemma
centroid_hom.cancel_right
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cancel_left {g f₁ f₂ : centroid_hom α} (hg : injective g) : g.comp f₁ = g.comp f₂ ↔ f₁ = f₂
⟨λ h, ext $ λ a, hg $ by rw [←comp_apply, h, comp_apply], congr_arg _⟩
lemma
centroid_hom.cancel_left
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_nsmul : has_smul ℕ (centroid_hom α)
⟨λ n f, { map_mul_left' := λ a b, by { change n • f (a * b) = a * n • f b, rw [map_mul_left f, ←mul_smul_comm] }, map_mul_right' := λ a b, by { change n • f (a * b) = n • f a * b, rw [map_mul_right f, ←smul_mul_assoc] }, .. (n • f : α →+ α) }⟩
instance
centroid_hom.has_nsmul
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom", "has_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_npow_nat : has_pow (centroid_hom α) ℕ
⟨λ f n, { map_mul_left' := λ a b, begin induction n with n ih, { simp }, { rw pow_succ, exact (congr_arg f.to_End ih).trans (f.map_mul_left' _ _) } end, map_mul_right' := λ a b, begin induction n with n ih, { simp }, { rw pow_succ, exact (congr_arg f.to_End ih).trans (f.map_mul_...
instance
centroid_hom.has_npow_nat
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "add_monoid.End", "centroid_hom", "ih", "pow_succ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_zero : ⇑(0 : centroid_hom α) = 0
rfl
lemma
centroid_hom.coe_zero
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_one : ⇑(1 : centroid_hom α) = id
rfl
lemma
centroid_hom.coe_one
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_add (f g : centroid_hom α) : ⇑(f + g) = f + g
rfl
lemma
centroid_hom.coe_add
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul (f g : centroid_hom α) : ⇑(f * g) = f ∘ g
rfl
lemma
centroid_hom.coe_mul
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_nsmul (f : centroid_hom α) (n : ℕ) : ⇑(n • f) = n • f
rfl
lemma
centroid_hom.coe_nsmul
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_apply (a : α) : (0 : centroid_hom α) a = 0
rfl
lemma
centroid_hom.zero_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_apply (a : α) : (1 : centroid_hom α) a = a
rfl
lemma
centroid_hom.one_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_apply (f g : centroid_hom α) (a : α) : (f + g) a = f a + g a
rfl
lemma
centroid_hom.add_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_apply (f g : centroid_hom α) (a : α) : (f * g) a = f (g a)
rfl
lemma
centroid_hom.mul_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nsmul_apply (f : centroid_hom α) (n : ℕ) (a : α) : (n • f) a = n • f a
rfl
lemma
centroid_hom.nsmul_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_zero : (0 : centroid_hom α).to_End = 0
rfl
lemma
centroid_hom.to_End_zero
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_add (x y : centroid_hom α) : (x + y).to_End = x.to_End + y.to_End
rfl
lemma
centroid_hom.to_End_add
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_nsmul (x : centroid_hom α) (n : ℕ) : (n • x).to_End = n • x.to_End
rfl
lemma
centroid_hom.to_End_nsmul
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_nat_cast (n : ℕ) : ⇑(n : centroid_hom α) = n • id
rfl
lemma
centroid_hom.coe_nat_cast
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_cast_apply (n : ℕ) (m : α): (n : centroid_hom α) m = n • m
rfl
lemma
centroid_hom.nat_cast_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_one : (1 : centroid_hom α).to_End = 1
rfl
lemma
centroid_hom.to_End_one
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_mul (x y : centroid_hom α) : (x * y).to_End = x.to_End * y.to_End
rfl
lemma
centroid_hom.to_End_mul
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_pow (x : centroid_hom α) (n : ℕ) : (x ^ n).to_End = x.to_End ^ n
by { ext, refl }
lemma
centroid_hom.to_End_pow
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_nat_cast (n : ℕ) : (n : centroid_hom α).to_End = ↑n
rfl
lemma
centroid_hom.to_End_nat_cast
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_mul_comm (T S : centroid_hom α) (a b : α) : (T ∘ S) (a * b) = (S ∘ T) (a * b)
by rw [comp_app, map_mul_right, map_mul_left, ←map_mul_right, ←map_mul_left]
lemma
centroid_hom.comp_mul_comm
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_zsmul : has_smul ℤ (centroid_hom α)
⟨λ n f, { map_mul_left' := λ a b, by { change n • f (a * b) = a * n • f b, rw [map_mul_left f, ←mul_smul_comm] }, map_mul_right' := λ a b, by { change n • f (a * b) = n • f a * b, rw [map_mul_right f, ←smul_mul_assoc] }, .. (n • f : α →+ α) }⟩
instance
centroid_hom.has_zsmul
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom", "has_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_int_cast (z : ℤ) : ⇑(z : centroid_hom α) = z • id
rfl
lemma
centroid_hom.coe_int_cast
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int_cast_apply (z : ℤ) (m : α) : (z : centroid_hom α) m = z • m
rfl
lemma
centroid_hom.int_cast_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_neg (x : centroid_hom α) : (-x).to_End = -x.to_End
rfl
lemma
centroid_hom.to_End_neg
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_sub (x y : centroid_hom α) : (x - y).to_End = x.to_End - y.to_End
rfl
lemma
centroid_hom.to_End_sub
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_zsmul (x : centroid_hom α) (n : ℤ) : (n • x).to_End = n • x.to_End
rfl
lemma
centroid_hom.to_End_zsmul
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_neg (f : centroid_hom α) : ⇑(-f) = -f
rfl
lemma
centroid_hom.coe_neg
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_sub (f g : centroid_hom α) : ⇑(f - g) = f - g
rfl
lemma
centroid_hom.coe_sub
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_apply (f : centroid_hom α) (a : α) : (-f) a = - f a
rfl
lemma
centroid_hom.neg_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_apply (f g : centroid_hom α) (a : α) : (f - g) a = f a - g a
rfl
lemma
centroid_hom.sub_apply
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_End_int_cast (z : ℤ) : (z : centroid_hom α).to_End = ↑z
rfl
lemma
centroid_hom.to_End_int_cast
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comm_ring (h : ∀ a b : α, (∀ r : α, a * r * b = 0) → a = 0 ∨ b = 0) : comm_ring (centroid_hom α)
{ mul_comm := λ f g, begin ext, refine sub_eq_zero.1 ((or_self _).1 $ h _ _ $ λ r, _), rw [mul_assoc, sub_mul, sub_eq_zero, ← map_mul_right, ← map_mul_right, coe_mul, coe_mul, comp_mul_comm], end, ..centroid_hom.ring }
def
centroid_hom.comm_ring
algebra.hom
src/algebra/hom/centroid.lean
[ "algebra.group_power.lemmas", "algebra.hom.group_instances" ]
[ "centroid_hom", "comm_ring", "mul_assoc", "mul_comm" ]
A prime associative ring has commutative centroid.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
semiconj_by.map [mul_hom_class F M N] (h : semiconj_by a x y) (f : F) : semiconj_by (f a) (f x) (f y)
by simpa only [semiconj_by, map_mul] using congr_arg f h
lemma
semiconj_by.map
algebra.hom
src/algebra/hom/commute.lean
[ "algebra.hom.group", "algebra.group.commute" ]
[ "map_mul", "mul_hom_class", "semiconj_by" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
commute.map [mul_hom_class F M N] (h : commute x y) (f : F) : commute (f x) (f y)
h.map f
lemma
commute.map
algebra.hom
src/algebra/hom/commute.lean
[ "algebra.hom.group", "algebra.group.commute" ]
[ "commute", "mul_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_left_embedding {G : Type*} [left_cancel_semigroup G] (g : G) : G ↪ G
{ to_fun := λ h, g * h, inj' := mul_right_injective g }
def
mul_left_embedding
algebra.hom
src/algebra/hom/embedding.lean
[ "algebra.group.defs", "logic.embedding.basic" ]
[ "left_cancel_semigroup", "mul_right_injective" ]
The embedding of a left cancellative semigroup into itself by left multiplication by a fixed element.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_right_embedding {G : Type*} [right_cancel_semigroup G] (g : G) : G ↪ G
{ to_fun := λ h, h * g, inj' := mul_left_injective g }
def
mul_right_embedding
algebra.hom
src/algebra/hom/embedding.lean
[ "algebra.group.defs", "logic.embedding.basic" ]
[ "mul_left_injective", "right_cancel_semigroup" ]
The embedding of a right cancellative semigroup into itself by right multiplication by a fixed element.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_left_embedding_eq_mul_right_embedding {G : Type*} [cancel_comm_monoid G] (g : G) : mul_left_embedding g = mul_right_embedding g
by { ext, exact mul_comm _ _ }
lemma
mul_left_embedding_eq_mul_right_embedding
algebra.hom
src/algebra/hom/embedding.lean
[ "algebra.group.defs", "logic.embedding.basic" ]
[ "cancel_comm_monoid", "mul_comm", "mul_left_embedding", "mul_right_embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_freiman_hom (A : set α) (β : Type*) [add_comm_monoid α] [add_comm_monoid β] (n : ℕ)
(to_fun : α → β) (map_sum_eq_map_sum' {s t : multiset α} (hsA : ∀ ⦃x⦄, x ∈ s → x ∈ A) (htA : ∀ ⦃x⦄, x ∈ t → x ∈ A) (hs : s.card = n) (ht : t.card = n) (h : s.sum = t.sum) : (s.map to_fun).sum = (t.map to_fun).sum)
structure
add_freiman_hom
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "add_comm_monoid", "multiset" ]
An additive `n`-Freiman homomorphism is a map which preserves sums of `n` elements.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
freiman_hom (A : set α) (β : Type*) [comm_monoid α] [comm_monoid β] (n : ℕ)
(to_fun : α → β) (map_prod_eq_map_prod' {s t : multiset α} (hsA : ∀ ⦃x⦄, x ∈ s → x ∈ A) (htA : ∀ ⦃x⦄, x ∈ t → x ∈ A) (hs : s.card = n) (ht : t.card = n) (h : s.prod = t.prod) : (s.map to_fun).prod = (t.map to_fun).prod)
structure
freiman_hom
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "comm_monoid", "multiset" ]
A `n`-Freiman homomorphism on a set `A` is a map which preserves products of `n` elements.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_freiman_hom_class (F : Type*) (A : out_param $ set α) (β : out_param $ Type*) [add_comm_monoid α] [add_comm_monoid β] (n : ℕ) [fun_like F α (λ _, β)] : Prop
(map_sum_eq_map_sum' (f : F) {s t : multiset α} (hsA : ∀ ⦃x⦄, x ∈ s → x ∈ A) (htA : ∀ ⦃x⦄, x ∈ t → x ∈ A) (hs : s.card = n) (ht : t.card = n) (h : s.sum = t.sum) : (s.map f).sum = (t.map f).sum)
class
add_freiman_hom_class
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "add_comm_monoid", "fun_like", "multiset" ]
`add_freiman_hom_class F s β n` states that `F` is a type of `n`-ary sums-preserving morphisms. You should extend this class when you extend `add_freiman_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
freiman_hom_class (F : Type*) (A : out_param $ set α) (β : out_param $ Type*) [comm_monoid α] [comm_monoid β] (n : ℕ) [fun_like F α (λ _, β)] : Prop
(map_prod_eq_map_prod' (f : F) {s t : multiset α} (hsA : ∀ ⦃x⦄, x ∈ s → x ∈ A) (htA : ∀ ⦃x⦄, x ∈ t → x ∈ A) (hs : s.card = n) (ht : t.card = n) (h : s.prod = t.prod) : (s.map f).prod = (t.map f).prod)
class
freiman_hom_class
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "comm_monoid", "fun_like", "multiset" ]
`freiman_hom_class F A β n` states that `F` is a type of `n`-ary products-preserving morphisms. You should extend this class when you extend `freiman_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_prod_eq_map_prod [freiman_hom_class F A β n] (f : F) {s t : multiset α} (hsA : ∀ ⦃x⦄, x ∈ s → x ∈ A) (htA : ∀ ⦃x⦄, x ∈ t → x ∈ A) (hs : s.card = n) (ht : t.card = n) (h : s.prod = t.prod) : (s.map f).prod = (t.map f).prod
freiman_hom_class.map_prod_eq_map_prod' f hsA htA hs ht h
lemma
map_prod_eq_map_prod
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "freiman_hom_class", "multiset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mul_map_eq_map_mul_map [freiman_hom_class F A β 2] (f : F) (ha : a ∈ A) (hb : b ∈ A) (hc : c ∈ A) (hd : d ∈ A) (h : a * b = c * d) : f a * f b = f c * f d
begin simp_rw ←prod_pair at ⊢ h, refine map_prod_eq_map_prod f _ _ (card_pair _ _) (card_pair _ _) h; simp [ha, hb, hc, hd], end
lemma
map_mul_map_eq_map_mul_map
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "freiman_hom_class", "map_prod_eq_map_prod" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fun_like : fun_like (A →*[n] β) α (λ _, β)
{ coe := to_fun, coe_injective' := λ f g h, by cases f; cases g; congr' }
instance
freiman_hom.fun_like
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "fun_like" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
freiman_hom_class : freiman_hom_class (A →*[n] β) A β n
{ map_prod_eq_map_prod' := map_prod_eq_map_prod' }
instance
freiman_hom.freiman_hom_class
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "freiman_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_fun_eq_coe (f : A →*[n] β) : f.to_fun = f
rfl
lemma
freiman_hom.to_fun_eq_coe
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext ⦃f g : A →*[n] β⦄ (h : ∀ x, f x = g x) : f = g
fun_like.ext f g h
lemma
freiman_hom.ext
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "fun_like.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mk (f : α → β) (h : ∀ s t : multiset α, (∀ ⦃x⦄, x ∈ s → x ∈ A) → (∀ ⦃x⦄, x ∈ t → x ∈ A) → s.card = n → t.card = n → s.prod = t.prod → (s.map f).prod = (t.map f).prod) : ⇑(mk f h) = f
rfl
lemma
freiman_hom.coe_mk
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "multiset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_coe (f : A →*[n] β) (h) : mk f h = f
ext $ λ _, rfl
lemma
freiman_hom.mk_coe
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id (A : set α) (n : ℕ) : A →*[n] α
{ to_fun := λ x, x, map_prod_eq_map_prod' := λ s t _ _ _ _ h, by rw [map_id', map_id', h] }
def
freiman_hom.id
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
The identity map from a commutative monoid to itself.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp (f : B →*[n] γ) (g : A →*[n] β) (hAB : A.maps_to g B) : A →*[n] γ
{ to_fun := f ∘ g, map_prod_eq_map_prod' := λ s t hsA htA hs ht h, begin rw [←map_map, map_prod_eq_map_prod f _ _ ((s.card_map _).trans hs) ((t.card_map _).trans ht) (map_prod_eq_map_prod g hsA htA hs ht h), map_map], { simpa using (λ a h, hAB (hsA h)) }, { simpa using (λ a h, hAB (htA h)) } e...
def
freiman_hom.comp
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "map_prod_eq_map_prod" ]
Composition of Freiman homomorphisms as a Freiman homomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_comp (f : B →*[n] γ) (g : A →*[n] β) {hfg} : ⇑(f.comp g hfg) = f ∘ g
rfl
lemma
freiman_hom.coe_comp
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_apply (f : B →*[n] γ) (g : A →*[n] β) {hfg} (x : α) : f.comp g hfg x = f (g x)
rfl
lemma
freiman_hom.comp_apply
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_assoc (f : A →*[n] β) (g : B →*[n] γ) (h : C →*[n] δ) {hf hhg hgf} {hh : A.maps_to (g.comp f hgf) C} : (h.comp g hhg).comp f hf = h.comp (g.comp f hgf) hh
rfl
lemma
freiman_hom.comp_assoc
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cancel_right {g₁ g₂ : B →*[n] γ} {f : A →*[n] β} (hf : function.surjective f) {hg₁ hg₂} : g₁.comp f hg₁ = g₂.comp f hg₂ ↔ g₁ = g₂
⟨λ h, ext $ hf.forall.2 $ fun_like.ext_iff.1 h, λ h, h ▸ rfl⟩
lemma
freiman_hom.cancel_right
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cancel_right_on {g₁ g₂ : B →*[n] γ} {f : A →*[n] β} (hf : A.surj_on f B) {hf'} : A.eq_on (g₁.comp f hf') (g₂.comp f hf') ↔ B.eq_on g₁ g₂
hf.cancel_right hf'
lemma
freiman_hom.cancel_right_on
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cancel_left_on {g : B →*[n] γ} {f₁ f₂ : A →*[n] β} (hg : B.inj_on g) {hf₁ hf₂} : A.eq_on (g.comp f₁ hf₁) (g.comp f₂ hf₂) ↔ A.eq_on f₁ f₂
hg.cancel_left hf₁ hf₂
lemma
freiman_hom.cancel_left_on
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_id (f : A →*[n] β) {hf} : f.comp (freiman_hom.id A n) hf = f
ext $ λ x, rfl
lemma
freiman_hom.comp_id
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "freiman_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id_comp (f : A →*[n] β) {hf} : (freiman_hom.id B n).comp f hf = f
ext $ λ x, rfl
lemma
freiman_hom.id_comp
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "freiman_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
const (A : set α) (n : ℕ) (b : β) : A →*[n] β
{ to_fun := λ _, b, map_prod_eq_map_prod' := λ s t _ _ hs ht _, by rw [multiset.map_const, multiset.map_const, prod_replicate, prod_replicate, hs, ht] }
def
freiman_hom.const
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "multiset.map_const" ]
`freiman_hom.const A n b` is the Freiman homomorphism sending everything to `b`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
const_apply (n : ℕ) (b : β) (x : α) : const A n b x = b
rfl
lemma
freiman_hom.const_apply
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
const_comp (n : ℕ) (c : γ) (f : A →*[n] β) {hf} : (const B n c).comp f hf = const A n c
rfl
lemma
freiman_hom.const_comp
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_apply (x : α) : (1 : A →*[n] β) x = 1
rfl
lemma
freiman_hom.one_apply
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_comp (f : A →*[n] β) {hf} : (1 : B →*[n] γ).comp f hf = 1
rfl
lemma
freiman_hom.one_comp
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_apply (f g : A →*[n] β) (x : α) : (f * g) x = f x * g x
rfl
lemma
freiman_hom.mul_apply
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_comp (g₁ g₂ : B →*[n] γ) (f : A →*[n] β) {hg hg₁ hg₂} : (g₁ * g₂).comp f hg = g₁.comp f hg₁ * g₂.comp f hg₂
rfl
lemma
freiman_hom.mul_comp
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_apply (f : A →*[n] G) (x : α) : f⁻¹ x = (f x)⁻¹
rfl
lemma
freiman_hom.inv_apply
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_comp (f : B →*[n] G) (g : A →*[n] β) {hf hf'} : f⁻¹.comp g hf = (f.comp g hf')⁻¹
ext $ λ x, rfl
lemma
freiman_hom.inv_comp
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_apply (f g : A →*[n] G) (x : α) : (f / g) x = f x / g x
rfl
lemma
freiman_hom.div_apply
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_comp (f₁ f₂ : B →*[n] G) (g : A →*[n] β) {hf hf₁ hf₂} : (f₁ / f₂).comp g hf = f₁.comp g hf₁ / f₂.comp g hf₂
ext $ λ x, rfl
lemma
freiman_hom.div_comp
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom.freiman_hom_class : freiman_hom_class (α →* β) set.univ β n
{ map_prod_eq_map_prod' := λ f s t _ _ _ _ h, by rw [←f.map_multiset_prod, h, f.map_multiset_prod] }
instance
monoid_hom.freiman_hom_class
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "freiman_hom_class" ]
A monoid homomorphism is naturally a `freiman_hom` on its entire domain. We can't leave the domain `A : set α` of the `freiman_hom` a free variable, since it wouldn't be inferrable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom.to_freiman_hom (A : set α) (n : ℕ) (f : α →* β) : A →*[n] β
{ to_fun := f, map_prod_eq_map_prod' := λ s t hsA htA, map_prod_eq_map_prod f (λ _ _, set.mem_univ _) (λ _ _, set.mem_univ _) }
def
monoid_hom.to_freiman_hom
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "map_prod_eq_map_prod", "set.mem_univ" ]
A `monoid_hom` is naturally a `freiman_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom.to_freiman_hom_coe (f : α →* β) : (f.to_freiman_hom A n : α → β) = f
rfl
lemma
monoid_hom.to_freiman_hom_coe
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom.to_freiman_hom_injective : function.injective (monoid_hom.to_freiman_hom A n : (α →* β) → A →*[n] β)
λ f g h, monoid_hom.ext $ show _, from fun_like.ext_iff.mp h
lemma
monoid_hom.to_freiman_hom_injective
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "monoid_hom.ext", "monoid_hom.to_freiman_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_prod_eq_map_prod_of_le [freiman_hom_class F A β n] (f : F) {s t : multiset α} (hsA : ∀ x ∈ s, x ∈ A) (htA : ∀ x ∈ t, x ∈ A) (hs : s.card = m) (ht : t.card = m) (hst : s.prod = t.prod) (h : m ≤ n) : (s.map f).prod = (t.map f).prod
begin obtain rfl | hm := m.eq_zero_or_pos, { rw card_eq_zero at hs ht, rw [hs, ht] }, rw [←hs, card_pos_iff_exists_mem] at hm, obtain ⟨a, ha⟩ := hm, suffices : ((s + replicate (n - m) a).map f).prod = ((t + replicate (n - m) a).map f).prod, { simp_rw [multiset.map_add, prod_add] at this, exact mul_r...
lemma
map_prod_eq_map_prod_of_le
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "add_tsub_cancel_of_le", "freiman_hom_class", "map_prod_eq_map_prod", "mul_right_cancel", "multiset", "multiset.map_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
freiman_hom.to_freiman_hom (h : m ≤ n) (f : A →*[n] β) : A →*[m] β
{ to_fun := f, map_prod_eq_map_prod' := λ s t hsA htA hs ht hst, map_prod_eq_map_prod_of_le f hsA htA hs ht hst h }
def
freiman_hom.to_freiman_hom
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "map_prod_eq_map_prod_of_le" ]
`α →*[n] β` is naturally included in `A →*[m] β` for any `m ≤ n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
freiman_hom.freiman_hom_class_of_le [freiman_hom_class F A β n] (h : m ≤ n) : freiman_hom_class F A β m
{ map_prod_eq_map_prod' := λ f s t hsA htA hs ht hst, map_prod_eq_map_prod_of_le f hsA htA hs ht hst h }
lemma
freiman_hom.freiman_hom_class_of_le
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "freiman_hom_class", "map_prod_eq_map_prod_of_le" ]
A `n`-Freiman homomorphism is also a `m`-Freiman homomorphism for any `m ≤ n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
freiman_hom.to_freiman_hom_coe (h : m ≤ n) (f : A →*[n] β) : (f.to_freiman_hom h : α → β) = f
rfl
lemma
freiman_hom.to_freiman_hom_coe
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
freiman_hom.to_freiman_hom_injective (h : m ≤ n) : function.injective (freiman_hom.to_freiman_hom h : (A →*[n] β) → A →*[m] β)
λ f g hfg, freiman_hom.ext $ by convert fun_like.ext_iff.1 hfg
lemma
freiman_hom.to_freiman_hom_injective
algebra.hom
src/algebra/hom/freiman.lean
[ "algebra.big_operators.multiset.basic", "data.fun_like.basic" ]
[ "freiman_hom.ext", "freiman_hom.to_freiman_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_hom (M : Type*) (N : Type*) [has_zero M] [has_zero N]
(to_fun : M → N) (map_zero' : to_fun 0 = 0)
structure
zero_hom
algebra.hom
src/algebra/hom/group.lean
[ "algebra.ne_zero", "algebra.group.basic", "algebra.group_with_zero.defs", "data.fun_like.basic" ]
[]
`zero_hom M N` is the type of functions `M → N` that preserve zero. When possible, instead of parametrizing results over `(f : zero_hom M N)`, you should parametrize over `(F : Type*) [zero_hom_class F M N] (f : F)`. When you extend this structure, make sure to also extend `zero_hom_class`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_hom_class (F : Type*) (M N : out_param $ Type*) [has_zero M] [has_zero N] extends fun_like F M (λ _, N)
(map_zero : ∀ (f : F), f 0 = 0)
class
zero_hom_class
algebra.hom
src/algebra/hom/group.lean
[ "algebra.ne_zero", "algebra.group.basic", "algebra.group_with_zero.defs", "data.fun_like.basic" ]
[ "fun_like" ]
`zero_hom_class F M N` states that `F` is a type of zero-preserving homomorphisms. You should extend this typeclass when you extend `zero_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_map {R M} [has_zero R] [has_zero M] [zero_hom_class F R M] (f : F) {r : R} [ne_zero (f r)] : ne_zero r
⟨λ h, ne (f r) $ by convert zero_hom_class.map_zero f⟩
lemma
ne_zero.of_map
algebra.hom
src/algebra/hom/group.lean
[ "algebra.ne_zero", "algebra.group.basic", "algebra.group_with_zero.defs", "data.fun_like.basic" ]
[ "ne_zero", "zero_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_injective {R M} [has_zero R] {r : R} [ne_zero r] [has_zero M] [zero_hom_class F R M] {f : F} (hf : function.injective f) : ne_zero (f r)
⟨by { rw ← zero_hom_class.map_zero f, exact hf.ne (ne r) }⟩
lemma
ne_zero.of_injective
algebra.hom
src/algebra/hom/group.lean
[ "algebra.ne_zero", "algebra.group.basic", "algebra.group_with_zero.defs", "data.fun_like.basic" ]
[ "ne_zero", "zero_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_hom (M : Type*) (N : Type*) [has_add M] [has_add N]
(to_fun : M → N) (map_add' : ∀ x y, to_fun (x + y) = to_fun x + to_fun y)
structure
add_hom
algebra.hom
src/algebra/hom/group.lean
[ "algebra.ne_zero", "algebra.group.basic", "algebra.group_with_zero.defs", "data.fun_like.basic" ]
[]
`add_hom M N` is the type of functions `M → N` that preserve addition. When possible, instead of parametrizing results over `(f : add_hom M N)`, you should parametrize over `(F : Type*) [add_hom_class F M N] (f : F)`. When you extend this structure, make sure to extend `add_hom_class`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_hom_class (F : Type*) (M N : out_param $ Type*) [has_add M] [has_add N] extends fun_like F M (λ _, N)
(map_add : ∀ (f : F) (x y : M), f (x + y) = f x + f y)
class
add_hom_class
algebra.hom
src/algebra/hom/group.lean
[ "algebra.ne_zero", "algebra.group.basic", "algebra.group_with_zero.defs", "data.fun_like.basic" ]
[ "fun_like" ]
`add_hom_class F M N` states that `F` is a type of addition-preserving homomorphisms. You should declare an instance of this typeclass when you extend `add_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_monoid_hom (M : Type*) (N : Type*) [add_zero_class M] [add_zero_class N] extends zero_hom M N, add_hom M N
structure
add_monoid_hom
algebra.hom
src/algebra/hom/group.lean
[ "algebra.ne_zero", "algebra.group.basic", "algebra.group_with_zero.defs", "data.fun_like.basic" ]
[ "add_hom", "add_zero_class", "zero_hom" ]
`M →+ N` is the type of functions `M → N` that preserve the `add_zero_class` structure. `add_monoid_hom` is also used for group homomorphisms. When possible, instead of parametrizing results over `(f : M →+ N)`, you should parametrize over `(F : Type*) [add_monoid_hom_class F M N] (f : F)`. When you extend this stru...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83