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tail_mul (x y : free_semigroup α) : (x * y).2 = x.2 ++ (y.1 :: y.2)
rfl
lemma
free_semigroup.tail_mul
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_mul_mk (x y : α) (L1 L2 : list α) : mk x L1 * mk y L2 = mk x (L1 ++ y :: L2)
rfl
lemma
free_semigroup.mk_mul_mk
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of (x : α) : free_semigroup α
⟨x, []⟩
def
free_semigroup.of
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
The embedding `α → free_semigroup α`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
length (x : free_semigroup α) : ℕ
x.tail.length + 1
def
free_semigroup.length
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
Length of an element of free semigroup.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
length_mul (x y : free_semigroup α) : (x * y).length = x.length + y.length
by simp [length, ← add_assoc, add_right_comm]
lemma
free_semigroup.length_mul
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
length_of (x : α) : (of x).length = 1
rfl
lemma
free_semigroup.length_of
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rec_on_mul {C : free_semigroup α → Sort l} (x) (ih1 : ∀ x, C (of x)) (ih2 : ∀ x y, C (of x) → C y → C (of x * y)) : C x
free_semigroup.rec_on x $ λ f s, list.rec_on s ih1 (λ hd tl ih f, ih2 f ⟨hd, tl⟩ (ih1 f) (ih hd)) f
def
free_semigroup.rec_on_mul
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "ih" ]
Recursor for free semigroup using `of` and `*`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_ext {β : Type v} [has_mul β] {f g : free_semigroup α →ₙ* β} (h : f ∘ of = g ∘ of) : f = g
fun_like.ext _ _ $ λ x, free_semigroup.rec_on_mul x (congr_fun h) $ λ x y hx hy, by simp only [map_mul, *]
lemma
free_semigroup.hom_ext
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "free_semigroup.rec_on_mul", "fun_like.ext", "hom_ext", "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift : (α → β) ≃ (free_semigroup α →ₙ* β)
{ to_fun := λ f, { to_fun := λ x, x.2.foldl (λ a b, a * f b) (f x.1), map_mul' := λ x y, by simp only [head_mul, tail_mul, ← list.foldl_map f, list.foldl_append, list.foldl_cons, list.foldl_assoc] }, inv_fun := λ f, f ∘ of, left_inv := λ f, rfl, right_inv := λ f, hom_ext rfl }
def
free_semigroup.lift
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "hom_ext", "inv_fun", "lift", "list.foldl_append", "list.foldl_assoc", "list.foldl_cons", "list.foldl_map" ]
Lifts a function `α → β` to a semigroup homomorphism `free_semigroup α → β` given a semigroup `β`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_comp_of' (f : free_semigroup α →ₙ* β) : lift (f ∘ of) = f
hom_ext rfl
lemma
free_semigroup.lift_comp_of'
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "hom_ext", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_of_mul (x y) : lift f (of x * y) = f x * lift f y
by rw [map_mul, lift_of]
lemma
free_semigroup.lift_of_mul
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "lift", "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map : free_semigroup α →ₙ* free_semigroup β
lift $ of ∘ f
def
free_semigroup.map
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "lift" ]
The unique semigroup homomorphism that sends `of x` to `of (f x)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
length_map (x) : (map f x).length = x.length
free_semigroup.rec_on_mul x (λ x, rfl) $ λ x y hx hy, by simp only [map_mul, length_mul, *]
lemma
free_semigroup.length_map
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup.rec_on_mul", "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rec_on_pure {C : free_semigroup α → Sort l} (x) (ih1 : ∀ x, C (pure x)) (ih2 : ∀ x y, C (pure x) → C y → C (pure x * y)) : C x
free_semigroup.rec_on_mul x ih1 ih2
def
free_semigroup.rec_on_pure
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "free_semigroup.rec_on_mul" ]
Recursor that uses `pure` instead of `of`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_pure (f : α → β) (x) : (f <$> pure x : free_semigroup β) = pure (f x)
rfl
lemma
free_semigroup.map_pure
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mul' (f : α → β) (x y : free_semigroup α) : (f <$> (x * y)) = (f <$> x * f <$> y)
map_mul (map f) _ _
lemma
free_semigroup.map_mul'
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pure_bind (f : α → free_semigroup β) (x) : (pure x >>= f) = f x
rfl
lemma
free_semigroup.pure_bind
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_bind (f : α → free_semigroup β) (x y : free_semigroup α) : (x * y >>= f) = ((x >>= f) * (y >>= f))
map_mul (lift f) _ _
lemma
free_semigroup.mul_bind
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "lift", "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pure_seq {f : α → β} {x : free_semigroup α} : pure f <*> x = f <$> x
rfl
lemma
free_semigroup.pure_seq
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_seq {f g : free_semigroup (α → β)} {x : free_semigroup α} : (f * g) <*> x = (f <*> x) * (g <*> x)
mul_bind _ _ _
lemma
free_semigroup.mul_seq
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
traverse {m : Type u → Type u} [applicative m] {α β : Type u} (F : α → m β) (x : free_semigroup α) : m (free_semigroup β)
rec_on_pure x (λ x, pure <$> F x) (λ x y ihx ihy, (*) <$> ihx <*> ihy)
def
free_semigroup.traverse
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
`free_semigroup` is traversable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
traverse_pure (x) :traverse F (pure x : free_semigroup α) = pure <$> F x
rfl
lemma
free_semigroup.traverse_pure
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
traverse_pure' : traverse F ∘ pure = λ x, (pure <$> F x : m (free_semigroup β))
rfl
lemma
free_semigroup.traverse_pure'
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
traverse_mul (x y : free_semigroup α) : traverse F (x * y) = (*) <$> traverse F x <*> traverse F y
let ⟨x, L1⟩ := x, ⟨y, L2⟩ := y in list.rec_on L1 (λ x, rfl) (λ hd tl ih x, show (*) <$> pure <$> F x <*> traverse F ((mk hd tl) * (mk y L2)) = (*) <$> ((*) <$> pure <$> F x <*> traverse F (mk hd tl)) <*> traverse F (mk y L2), by rw ih; simp only [(∘), (mul_assoc _ _ _).symm] with functor_norm) x
lemma
free_semigroup.traverse_mul
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup", "ih", "mul_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
traverse_mul' : function.comp (traverse F) ∘ @has_mul.mul (free_semigroup α) _ = λ x y, (*) <$> traverse F x <*> traverse F y
funext $ λ x, funext $ λ y, traverse_mul F x y
lemma
free_semigroup.traverse_mul'
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
traverse_eq (x) : free_semigroup.traverse F x = traverse F x
rfl
lemma
free_semigroup.traverse_eq
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup.traverse" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_map_seq (x y : free_semigroup α) : ((*) <$> x <*> y : id (free_semigroup α)) = (x * y : free_semigroup α)
rfl
lemma
free_semigroup.mul_map_seq
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_free_semigroup : free_magma α →ₙ* free_semigroup α
free_magma.lift free_semigroup.of
def
free_magma.to_free_semigroup
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_magma", "free_magma.lift", "free_semigroup", "free_semigroup.of" ]
The canonical multiplicative morphism from `free_magma α` to `free_semigroup α`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_free_semigroup_of (x : α) : to_free_semigroup (of x) = free_semigroup.of x
rfl
lemma
free_magma.to_free_semigroup_of
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup.of" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_free_semigroup_comp_of : @to_free_semigroup α ∘ of = free_semigroup.of
rfl
lemma
free_magma.to_free_semigroup_comp_of
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup.of" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_free_semigroup_comp_map (f : α → β) : to_free_semigroup.comp (map f) = (free_semigroup.map f).comp to_free_semigroup
by { ext1, refl }
lemma
free_magma.to_free_semigroup_comp_map
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_semigroup.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_free_semigroup_map (f : α → β) (x : free_magma α) : (map f x).to_free_semigroup = free_semigroup.map f x.to_free_semigroup
fun_like.congr_fun (to_free_semigroup_comp_map f) x
lemma
free_magma.to_free_semigroup_map
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_magma", "free_semigroup.map", "fun_like.congr_fun" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
length_to_free_semigroup (x : free_magma α) : x.to_free_semigroup.length = x.length
free_magma.rec_on_mul x (λ x, rfl) $ λ x y hx hy, by rw [map_mul, free_semigroup.length_mul, length, hx, hy]
lemma
free_magma.length_to_free_semigroup
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_magma", "free_magma.rec_on_mul", "free_semigroup.length_mul", "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
free_magma_assoc_quotient_equiv (α : Type u) : magma.assoc_quotient (free_magma α) ≃* free_semigroup α
(magma.assoc_quotient.lift free_magma.to_free_semigroup).to_mul_equiv (free_semigroup.lift (magma.assoc_quotient.of ∘ free_magma.of)) (by { ext, refl }) (by { ext1, refl })
def
free_magma_assoc_quotient_equiv
algebra
src/algebra/free.lean
[ "algebra.hom.group", "algebra.hom.equiv.basic", "control.applicative", "control.traversable.basic", "logic.equiv.defs", "data.list.basic" ]
[ "free_magma", "free_magma.to_free_semigroup", "free_semigroup", "free_semigroup.lift", "magma.assoc_quotient", "magma.assoc_quotient.lift", "magma.assoc_quotient.of" ]
Isomorphism between `magma.assoc_quotient (free_magma α)` and `free_semigroup α`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pre | of : X → pre | of_scalar : R → pre | add : pre → pre → pre | mul : pre → pre → pre
inductive
free_algebra.pre
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[]
This inductive type is used to express representatives of the free algebra.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coe_generator : has_coe X (pre R X)
⟨of⟩
def
free_algebra.pre.has_coe_generator
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[]
Coercion from `X` to `pre R X`. Note: Used for notation only.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coe_semiring : has_coe R (pre R X)
⟨of_scalar⟩
def
free_algebra.pre.has_coe_semiring
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[]
Coercion from `R` to `pre R X`. Note: Used for notation only.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_mul : has_mul (pre R X)
⟨mul⟩
def
free_algebra.pre.has_mul
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[]
Multiplication in `pre R X` defined as `pre.mul`. Note: Used for notation only.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_add : has_add (pre R X)
⟨add⟩
def
free_algebra.pre.has_add
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[]
Addition in `pre R X` defined as `pre.add`. Note: Used for notation only.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_zero : has_zero (pre R X)
⟨of_scalar 0⟩
def
free_algebra.pre.has_zero
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[]
Zero in `pre R X` defined as the image of `0` from `R`. Note: Used for notation only.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_one : has_one (pre R X)
⟨of_scalar 1⟩
def
free_algebra.pre.has_one
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[]
One in `pre R X` defined as the image of `1` from `R`. Note: Used for notation only.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_smul : has_smul R (pre R X)
⟨λ r m, mul (of_scalar r) m⟩
def
free_algebra.pre.has_smul
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "has_smul" ]
Scalar multiplication defined as multiplication by the image of elements from `R`. Note: Used for notation only.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_fun {A : Type*} [semiring A] [algebra R A] (f : X → A) : pre R X → A
λ t, pre.rec_on t f (algebra_map _ _) (λ _ _, (+)) (λ _ _, (*))
def
free_algebra.lift_fun
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "algebra", "algebra_map", "semiring" ]
Given a function from `X` to an `R`-algebra `A`, `lift_fun` provides a lift of `f` to a function from `pre R X` to `A`. This is mainly used in the construction of `free_algebra.lift`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel : (pre R X) → (pre R X) → Prop -- force `of_scalar` to be a central semiring morphism | add_scalar {r s : R} : rel ↑(r + s) (↑r + ↑s) | mul_scalar {r s : R} : rel ↑(r * s) (↑r * ↑s) | central_scalar {r : R} {a : pre R X} : rel (r * a) (a * r) -- commutative additive semigroup | add_assoc {a b c : pre R X} : rel (a ...
inductive
free_algebra.rel
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "left_distrib", "mul_assoc", "mul_one", "mul_zero", "one_mul", "rel", "right_distrib", "zero_mul" ]
An inductively defined relation on `pre R X` used to force the initial algebra structure on the associated quotient.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
free_algebra
quot (free_algebra.rel R X)
def
free_algebra
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra.rel" ]
The free algebra for the type `X` over the commutative semiring `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι : X → free_algebra R X
λ m, quot.mk _ m
def
free_algebra.ι
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra" ]
The canonical function `X → free_algebra R X`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_mk_eq_ι (m : X) : quot.mk (free_algebra.rel R X) m = ι R m
by rw [ι]
lemma
free_algebra.quot_mk_eq_ι
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra.rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_aux (f : X → A) : (free_algebra R X →ₐ[R] A)
{ to_fun := λ a, quot.lift_on a (lift_fun _ _ f) $ λ a b h, begin induction h, { exact (algebra_map R A).map_add h_r h_s, }, { exact (algebra_map R A).map_mul h_r h_s }, { apply algebra.commutes }, { change _ + _ + _ = _ + (_ + _), rw add_assoc }, { change _ + _ = _ + _, rw add_com...
def
free_algebra.lift_aux
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "algebra.commutes", "algebra_map", "free_algebra", "left_distrib", "map_mul", "mul_assoc", "right_distrib" ]
Internal definition used to define `lift`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift : (X → A) ≃ (free_algebra R X →ₐ[R] A)
{ to_fun := lift_aux R, inv_fun := λ F, F ∘ (ι R), left_inv := λ f, by {ext, rw [ι], refl}, right_inv := λ F, by { ext x, rcases x, induction x, case pre.of : { change ((F : free_algebra R X → A) ∘ (ι R)) _ = _, rw [ι], refl }, case pre.of_scalar : { change algebra_map _ _ x ...
def
free_algebra.lift
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "alg_hom.commutes", "alg_hom.map_add", "alg_hom.map_mul", "algebra_map", "free_algebra", "inv_fun", "lift" ]
Given a function `f : X → A` where `A` is an `R`-algebra, `lift R f` is the unique lift of `f` to a morphism of `R`-algebras `free_algebra R X → A`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_aux_eq (f : X → A) : lift_aux R f = lift R f
by { rw [lift], refl }
lemma
free_algebra.lift_aux_eq
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_symm_apply (F : free_algebra R X →ₐ[R] A) : (lift R).symm F = F ∘ (ι R)
by { rw [lift], refl }
lemma
free_algebra.lift_symm_apply
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_comp_lift (f : X → A) : (lift R f : free_algebra R X → A) ∘ (ι R) = f
by { ext, rw [ι, lift], refl }
theorem
free_algebra.ι_comp_lift
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_ι_apply (f : X → A) (x) : lift R f (ι R x) = f x
by { rw [ι, lift], refl }
theorem
free_algebra.lift_ι_apply
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_unique (f : X → A) (g : free_algebra R X →ₐ[R] A) : (g : free_algebra R X → A) ∘ (ι R) = f ↔ g = lift R f
by { rw [← (lift R).symm_apply_eq, lift], refl }
theorem
free_algebra.lift_unique
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra", "lift", "lift_unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_comp_ι (g : free_algebra R X →ₐ[R] A) : lift R ((g : free_algebra R X → A) ∘ (ι R)) = g
by { rw ←lift_symm_apply, exact (lift R).apply_symm_apply g }
theorem
free_algebra.lift_comp_ι
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_ext {f g : free_algebra R X →ₐ[R] A} (w : ((f : free_algebra R X → A) ∘ (ι R)) = ((g : free_algebra R X → A) ∘ (ι R))) : f = g
begin rw [←lift_symm_apply, ←lift_symm_apply] at w, exact (lift R).symm.injective w, end
theorem
free_algebra.hom_ext
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra", "hom_ext", "lift" ]
See note [partially-applied ext lemmas].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_monoid_algebra_free_monoid : free_algebra R X ≃ₐ[R] monoid_algebra R (free_monoid X)
alg_equiv.of_alg_hom (lift R (λ x, (monoid_algebra.of R (free_monoid X)) (free_monoid.of x))) ((monoid_algebra.lift R (free_monoid X) (free_algebra R X)) (free_monoid.lift (ι R))) begin apply monoid_algebra.alg_hom_ext, intro x, apply free_monoid.rec_on x, { simp, refl, }, { intros x y ih, simp at ih, simp ...
def
free_algebra.equiv_monoid_algebra_free_monoid
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "alg_equiv.of_alg_hom", "free_algebra", "free_monoid", "free_monoid.lift", "free_monoid.of", "free_monoid.rec_on", "ih", "lift", "monoid_algebra", "monoid_algebra.alg_hom_ext", "monoid_algebra.lift", "monoid_algebra.of" ]
The free algebra on `X` is "just" the monoid algebra on the free monoid on `X`. This would be useful when constructing linear maps out of a free algebra, for example.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_inv : free_algebra R X →ₐ[R] R
lift R (0 : X → R)
def
free_algebra.algebra_map_inv
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra", "lift" ]
The left-inverse of `algebra_map`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_left_inverse : function.left_inverse algebra_map_inv (algebra_map R $ free_algebra R X)
λ x, by simp [algebra_map_inv]
lemma
free_algebra.algebra_map_left_inverse
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "algebra_map", "free_algebra" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_inj (x y : R) : algebra_map R (free_algebra R X) x = algebra_map R (free_algebra R X) y ↔ x = y
algebra_map_left_inverse.injective.eq_iff
lemma
free_algebra.algebra_map_inj
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "algebra_map", "free_algebra" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_eq_zero_iff (x : R) : algebra_map R (free_algebra R X) x = 0 ↔ x = 0
map_eq_zero_iff (algebra_map _ _) algebra_map_left_inverse.injective
lemma
free_algebra.algebra_map_eq_zero_iff
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "algebra_map", "free_algebra" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_eq_one_iff (x : R) : algebra_map R (free_algebra R X) x = 1 ↔ x = 1
map_eq_one_iff (algebra_map _ _) algebra_map_left_inverse.injective
lemma
free_algebra.algebra_map_eq_one_iff
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "algebra_map", "free_algebra", "map_eq_one_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_injective [nontrivial R] : function.injective (ι R : X → free_algebra R X)
λ x y hoxy, classical.by_contradiction $ by classical; exact assume hxy : x ≠ y, let f : free_algebra R X →ₐ[R] R := lift R (λ z, if x = z then (1 : R) else 0) in have hfx1 : f (ι R x) = 1, from (lift_ι_apply _ _).trans $ if_pos rfl, have hfy1 : f (ι R y) = 1, from hoxy ▸ hfx1, have hfy0 : f (ι R y) = 0, fr...
lemma
free_algebra.ι_injective
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "free_algebra", "lift", "nontrivial", "one_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_inj [nontrivial R] (x y : X) : ι R x = ι R y ↔ x = y
ι_injective.eq_iff
lemma
free_algebra.ι_inj
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "nontrivial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_ne_algebra_map [nontrivial R] (x : X) (r : R) : ι R x ≠ algebra_map R _ r
λ h, let f0 : free_algebra R X →ₐ[R] R := lift R 0 in let f1 : free_algebra R X →ₐ[R] R := lift R 1 in have hf0 : f0 (ι R x) = 0, from lift_ι_apply _ _, have hf1 : f1 (ι R x) = 1, from lift_ι_apply _ _, begin rw [h, f0.commutes, algebra.id.map_eq_self] at hf0, rw [h, f1.commutes, algebra.id.map_eq_sel...
lemma
free_algebra.ι_ne_algebra_map
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "algebra.id.map_eq_self", "algebra_map", "free_algebra", "lift", "nontrivial", "zero_ne_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_ne_zero [nontrivial R] (x : X) : ι R x ≠ 0
ι_ne_algebra_map x 0
lemma
free_algebra.ι_ne_zero
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "nontrivial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_ne_one [nontrivial R] (x : X) : ι R x ≠ 1
ι_ne_algebra_map x 1
lemma
free_algebra.ι_ne_one
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "nontrivial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
induction {C : free_algebra R X → Prop} (h_grade0 : ∀ r, C (algebra_map R (free_algebra R X) r)) (h_grade1 : ∀ x, C (ι R x)) (h_mul : ∀ a b, C a → C b → C (a * b)) (h_add : ∀ a b, C a → C b → C (a + b)) (a : free_algebra R X) : C a
begin -- the arguments are enough to construct a subalgebra, and a mapping into it from X let s : subalgebra R (free_algebra R X) := { carrier := C, mul_mem' := h_mul, add_mem' := h_add, algebra_map_mem' := h_grade0, }, let of : X → s := subtype.coind (ι R) h_grade1, -- the mapping through the sub...
lemma
free_algebra.induction
algebra
src/algebra/free_algebra.lean
[ "algebra.algebra.subalgebra.basic", "algebra.monoid_algebra.basic" ]
[ "alg_hom.ext_iff", "alg_hom.id", "algebra_map", "free_algebra", "lift", "subalgebra", "subtype.coind", "subtype.prop" ]
An induction principle for the free algebra. If `C` holds for the `algebra_map` of `r : R` into `free_algebra R X`, the `ι` of `x : X`, and is preserved under addition and muliplication, then it holds for all of `free_algebra R X`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
free_non_unital_non_assoc_algebra
monoid_algebra R (free_magma X)
abbreviation
free_non_unital_non_assoc_algebra
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "free_magma", "monoid_algebra" ]
The free non-unital, non-associative algebra on the type `X` with coefficients in `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of : X → free_non_unital_non_assoc_algebra R X
(monoid_algebra.of_magma R _) ∘ free_magma.of
def
free_non_unital_non_assoc_algebra.of
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "free_non_unital_non_assoc_algebra", "monoid_algebra.of_magma" ]
The embedding of `X` into the free algebra with coefficients in `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift : (X → A) ≃ (free_non_unital_non_assoc_algebra R X →ₙₐ[R] A)
free_magma.lift.trans (monoid_algebra.lift_magma R)
def
free_non_unital_non_assoc_algebra.lift
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "free_non_unital_non_assoc_algebra", "lift", "monoid_algebra.lift_magma" ]
The functor `X ↦ free_non_unital_non_assoc_algebra R X` from the category of types to the category of non-unital, non-associative algebras over `R` is adjoint to the forgetful functor in the other direction.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_symm_apply (F : free_non_unital_non_assoc_algebra R X →ₙₐ[R] A) : (lift R).symm F = F ∘ (of R)
rfl
lemma
free_non_unital_non_assoc_algebra.lift_symm_apply
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "free_non_unital_non_assoc_algebra", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_comp_lift (f : X → A) : (lift R f) ∘ (of R) = f
(lift R).left_inv f
lemma
free_non_unital_non_assoc_algebra.of_comp_lift
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_unique (f : X → A) (F : free_non_unital_non_assoc_algebra R X →ₙₐ[R] A) : F ∘ (of R) = f ↔ F = lift R f
(lift R).symm_apply_eq
lemma
free_non_unital_non_assoc_algebra.lift_unique
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "free_non_unital_non_assoc_algebra", "lift", "lift_unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_of_apply (f : X → A) (x) : lift R f (of R x) = f x
congr_fun (of_comp_lift _ f) x
lemma
free_non_unital_non_assoc_algebra.lift_of_apply
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_comp_of (F : free_non_unital_non_assoc_algebra R X →ₙₐ[R] A) : lift R (F ∘ (of R)) = F
(lift R).apply_symm_apply F
lemma
free_non_unital_non_assoc_algebra.lift_comp_of
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "free_non_unital_non_assoc_algebra", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_ext {F₁ F₂ : free_non_unital_non_assoc_algebra R X →ₙₐ[R] A} (h : ∀ x, F₁ (of R x) = F₂ (of R x)) : F₁ = F₂
(lift R).symm.injective $ funext h
lemma
free_non_unital_non_assoc_algebra.hom_ext
algebra
src/algebra/free_non_unital_non_assoc_algebra.lean
[ "algebra.free", "algebra.monoid_algebra.basic" ]
[ "free_non_unital_non_assoc_algebra", "hom_ext", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum_succ {x : α} {n : ℕ} : ∑ i in range (n + 1), x ^ i = x * ∑ i in range n, x ^ i + 1
by simp only [mul_sum, ←pow_succ, sum_range_succ', pow_zero]
lemma
geom_sum_succ
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "pow_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum_succ' {x : α} {n : ℕ} : ∑ i in range (n + 1), x ^ i = x ^ n + ∑ i in range n, x ^ i
(sum_range_succ _ _).trans (add_comm _ _)
lemma
geom_sum_succ'
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum_zero (x : α) : ∑ i in range 0, x ^ i = 0
rfl
theorem
geom_sum_zero
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum_one (x : α) : ∑ i in range 1, x ^ i = 1
by simp [geom_sum_succ']
theorem
geom_sum_one
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "geom_sum_succ'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum_two {x : α} : ∑ i in range 2, x ^ i = x + 1
by simp [geom_sum_succ']
lemma
geom_sum_two
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "geom_sum_succ'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_geom_sum : ∀ {n}, ∑ i in range n, (0 : α) ^ i = if n = 0 then 0 else 1
| 0 := by simp | 1 := by simp | (n+2) := by { rw geom_sum_succ', simp [zero_geom_sum] }
lemma
zero_geom_sum
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "geom_sum_succ'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_geom_sum (n : ℕ) : ∑ i in range n, (1 : α) ^ i = n
by simp
lemma
one_geom_sum
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_geom_sum (x : α) (n : ℕ) : op (∑ i in range n, x ^ i) = ∑ i in range n, (op x) ^ i
by simp
lemma
op_geom_sum
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_geom_sum₂ (x y : α) (n : ℕ) : op (∑ i in range n, x ^ i * (y ^ (n - 1 - i))) = ∑ i in range n, (op y) ^ i * ((op x) ^ (n - 1 - i))
begin simp only [op_sum, op_mul, op_pow], rw ← sum_range_reflect, refine sum_congr rfl (λ j j_in, _), rw [mem_range, nat.lt_iff_add_one_le] at j_in, congr, apply tsub_tsub_cancel_of_le, exact le_tsub_of_add_le_right j_in end
lemma
op_geom_sum₂
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "le_tsub_of_add_le_right", "nat.lt_iff_add_one_le", "tsub_tsub_cancel_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum₂_with_one (x : α) (n : ℕ) : ∑ i in range n, x ^ i * (1 ^ (n - 1 - i)) = ∑ i in range n, x ^ i
sum_congr rfl (λ i _, by { rw [one_pow, mul_one] })
theorem
geom_sum₂_with_one
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "mul_one", "one_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
commute.geom_sum₂_mul_add {x y : α} (h : commute x y) (n : ℕ) : (∑ i in range n, (x + y) ^ i * (y ^ (n - 1 - i))) * x + y ^ n = (x + y) ^ n
begin let f := λ (m i : ℕ), (x + y) ^ i * y ^ (m - 1 - i), change (∑ i in range n, (f n) i) * x + y ^ n = (x + y) ^ n, induction n with n ih, { rw [range_zero, sum_empty, zero_mul, zero_add, pow_zero, pow_zero] }, { have f_last : f (n + 1) n = (x + y) ^ n := by { dsimp [f], rw [← tsub_add_eq_ts...
theorem
commute.geom_sum₂_mul_add
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "add_tsub_cancel_of_le", "add_tsub_cancel_right", "commute", "commute.refl", "ih", "mul_assoc", "mul_one", "pow_succ", "pow_zero", "tsub_add_eq_tsub_tsub", "tsub_self", "zero_mul" ]
$x^n-y^n = (x-y) \sum x^ky^{n-1-k}$ reformulated without `-` signs.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_one_geom_sum [ring α] {n : ℕ} : ∑ i in range n, (-1 : α) ^ i = if even n then 0 else 1
begin induction n with k hk, { simp }, { simp only [geom_sum_succ', nat.even_add_one, hk], split_ifs, { rw [h.neg_one_pow, add_zero] }, { rw [(nat.odd_iff_not_even.2 h).neg_one_pow, neg_add_self] } } end
lemma
neg_one_geom_sum
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "geom_sum_succ'", "nat.even_add_one", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum₂_self {α : Type*} [comm_ring α] (x : α) (n : ℕ) : ∑ i in range n, x ^ i * (x ^ (n - 1 - i)) = n * x ^ (n-1)
calc ∑ i in finset.range n, x ^ i * x ^ (n - 1 - i) = ∑ i in finset.range n, x ^ (i + (n - 1 - i)) : by simp_rw [← pow_add] ... = ∑ i in finset.range n, x ^ (n - 1) : finset.sum_congr rfl (λ i hi, congr_arg _ $ add_tsub_cancel_of_le $ nat.le_pred_of_lt $ finset.mem_range.1 hi) ... = (finset.range n).card • (x ^ ...
theorem
geom_sum₂_self
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "add_tsub_cancel_of_le", "comm_ring", "finset.card_range", "finset.range", "nat.le_pred_of_lt", "nsmul_eq_mul", "pow_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum₂_mul_add [comm_semiring α] (x y : α) (n : ℕ) : (∑ i in range n, (x + y) ^ i * (y ^ (n - 1 - i))) * x + y ^ n = (x + y) ^ n
(commute.all x y).geom_sum₂_mul_add n
theorem
geom_sum₂_mul_add
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "comm_semiring", "commute.all" ]
$x^n-y^n = (x-y) \sum x^ky^{n-1-k}$ reformulated without `-` signs.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum_mul_add [semiring α] (x : α) (n : ℕ) : (∑ i in range n, (x + 1) ^ i) * x + 1 = (x + 1) ^ n
begin have := (commute.one_right x).geom_sum₂_mul_add n, rw [one_pow, geom_sum₂_with_one] at this, exact this end
theorem
geom_sum_mul_add
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "commute.one_right", "geom_sum₂_mul_add", "geom_sum₂_with_one", "one_pow", "semiring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
commute.geom_sum₂_mul [ring α] {x y : α} (h : commute x y) (n : ℕ) : (∑ i in range n, x ^ i * (y ^ (n - 1 - i))) * (x - y) = x ^ n - y ^ n
begin have := (h.sub_left (commute.refl y)).geom_sum₂_mul_add n, rw [sub_add_cancel] at this, rw [← this, add_sub_cancel] end
theorem
commute.geom_sum₂_mul
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "commute", "commute.refl", "geom_sum₂_mul_add", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
commute.mul_neg_geom_sum₂ [ring α] {x y : α} (h : commute x y) (n : ℕ) : (y - x) * (∑ i in range n, x ^ i * (y ^ (n - 1 - i))) = y ^ n - x ^ n
begin apply op_injective, simp only [op_mul, op_sub, op_geom_sum₂, op_pow], exact (commute.op h.symm).geom_sum₂_mul n end
lemma
commute.mul_neg_geom_sum₂
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "commute", "commute.op", "geom_sum₂_mul", "op_geom_sum₂", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
commute.mul_geom_sum₂ [ring α] {x y : α} (h : commute x y) (n : ℕ) : (x - y) * (∑ i in range n, x ^ i * (y ^ (n - 1 - i))) = x ^ n - y ^ n
by rw [← neg_sub (y ^ n), ← h.mul_neg_geom_sum₂, ← neg_mul, neg_sub]
lemma
commute.mul_geom_sum₂
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "commute", "neg_mul", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum₂_mul [comm_ring α] (x y : α) (n : ℕ) : (∑ i in range n, x ^ i * (y ^ (n - 1 - i))) * (x - y) = x ^ n - y ^ n
(commute.all x y).geom_sum₂_mul n
theorem
geom_sum₂_mul
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "comm_ring", "commute.all" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_dvd_pow_sub_pow [comm_ring α] (x y : α) (n : ℕ) : x - y ∣ x ^ n - y ^ n
dvd.intro_left _ (geom_sum₂_mul x y n)
theorem
sub_dvd_pow_sub_pow
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "comm_ring", "dvd.intro_left", "geom_sum₂_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_sub_dvd_pow_sub_pow (x y n : ℕ) : x - y ∣ x ^ n - y ^ n
begin cases le_or_lt y x with h, { have : y ^ n ≤ x ^ n := nat.pow_le_pow_of_le_left h _, exact_mod_cast sub_dvd_pow_sub_pow (x : ℤ) ↑y n }, { have : x ^ n ≤ y ^ n := nat.pow_le_pow_of_le_left h.le _, exact (nat.sub_eq_zero_of_le this).symm ▸ dvd_zero (x - y) } end
theorem
nat_sub_dvd_pow_sub_pow
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "dvd_zero", "nat.pow_le_pow_of_le_left", "sub_dvd_pow_sub_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
odd.add_dvd_pow_add_pow [comm_ring α] (x y : α) {n : ℕ} (h : odd n) : x + y ∣ x ^ n + y ^ n
begin have h₁ := geom_sum₂_mul x (-y) n, rw [odd.neg_pow h y, sub_neg_eq_add, sub_neg_eq_add] at h₁, exact dvd.intro_left _ h₁, end
theorem
odd.add_dvd_pow_add_pow
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "comm_ring", "dvd.intro_left", "geom_sum₂_mul", "odd", "odd.neg_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
odd.nat_add_dvd_pow_add_pow (x y : ℕ) {n : ℕ} (h : odd n) : x + y ∣ x ^ n + y ^ n
by exact_mod_cast odd.add_dvd_pow_add_pow (x : ℤ) ↑y h
theorem
odd.nat_add_dvd_pow_add_pow
algebra
src/algebra/geom_sum.lean
[ "algebra.big_operators.order", "algebra.big_operators.ring", "algebra.big_operators.intervals", "tactic.abel", "data.nat.parity" ]
[ "odd", "odd.add_dvd_pow_add_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83