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norm_sq_inv : norm_sq a⁻¹ = (norm_sq a)⁻¹
map_inv₀ norm_sq _
lemma
quaternion.norm_sq_inv
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "map_inv₀" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_sq_div : norm_sq (a / b) = norm_sq a / norm_sq b
map_div₀ norm_sq a b
lemma
quaternion.norm_sq_div
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "map_div₀" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_sq_zpow (z : ℤ) : norm_sq (a ^ z) = norm_sq a ^ z
map_zpow₀ norm_sq a z
lemma
quaternion.norm_sq_zpow
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "map_zpow₀" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_sq_rat_cast (q : ℚ) : norm_sq (q : ℍ[R]) = q^2
by rw [←coe_rat_cast, norm_sq_coe]
lemma
quaternion.norm_sq_rat_cast
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_four [infinite R] : #R ^ 4 = #R
power_nat_eq (aleph_0_le_mk R) $ by simp
theorem
cardinal.pow_four
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_quaternion_algebra : #ℍ[R, c₁, c₂] = #R ^ 4
by { rw mk_congr (quaternion_algebra.equiv_prod c₁ c₂), simp only [mk_prod, lift_id], ring }
lemma
cardinal.mk_quaternion_algebra
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "quaternion_algebra.equiv_prod", "ring" ]
The cardinality of a quaternion algebra, as a type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_quaternion_algebra_of_infinite [infinite R] : #ℍ[R, c₁, c₂] = #R
by rw [mk_quaternion_algebra, pow_four]
lemma
cardinal.mk_quaternion_algebra_of_infinite
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_univ_quaternion_algebra : #(set.univ : set ℍ[R, c₁, c₂]) = #R ^ 4
by rw [mk_univ, mk_quaternion_algebra]
lemma
cardinal.mk_univ_quaternion_algebra
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[]
The cardinality of a quaternion algebra, as a set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_univ_quaternion_algebra_of_infinite [infinite R] : #(set.univ : set ℍ[R, c₁, c₂]) = #R
by rw [mk_univ_quaternion_algebra, pow_four]
lemma
cardinal.mk_univ_quaternion_algebra_of_infinite
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_quaternion : #ℍ[R] = #R ^ 4
mk_quaternion_algebra _ _
lemma
cardinal.mk_quaternion
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[]
The cardinality of the quaternions, as a type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_quaternion_of_infinite [infinite R] : #ℍ[R] = #R
by rw [mk_quaternion, pow_four]
lemma
cardinal.mk_quaternion_of_infinite
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_univ_quaternion : #(set.univ : set ℍ[R]) = #R ^ 4
mk_univ_quaternion_algebra _ _
lemma
cardinal.mk_univ_quaternion
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[]
The cardinality of the quaternions, as a set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_univ_quaternion_of_infinite [infinite R] : #(set.univ : set ℍ[R]) = #R
by rw [mk_univ_quaternion, pow_four]
lemma
cardinal.mk_univ_quaternion_of_infinite
algebra
src/algebra/quaternion.lean
[ "algebra.algebra.equiv", "linear_algebra.finrank", "linear_algebra.free_module.basic", "linear_algebra.free_module.finite.basic", "set_theory.cardinal.ordinal", "tactic.ring_exp" ]
[ "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
basis {R : Type*} (A : Type*) [comm_ring R] [ring A] [algebra R A] (c₁ c₂ : R)
(i j k : A) (i_mul_i : i * i = c₁ • 1) (j_mul_j : j * j = c₂ • 1) (i_mul_j : i * j = k) (j_mul_i : j * i = -k)
structure
quaternion_algebra.basis
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "algebra", "basis", "comm_ring", "ring" ]
A quaternion basis contains the information both sufficient and necessary to construct an `R`-algebra homomorphism from `ℍ[R,c₁,c₂]` to `A`; or equivalently, a surjective `R`-algebra homomorphism from `ℍ[R,c₁,c₂]` to an `R`-subalgebra of `A`. Note that for definitional convenience, `k` is provided as a field even thou...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext ⦃q₁ q₂ : basis A c₁ c₂⦄ (hi : q₁.i = q₂.i) (hj : q₁.j = q₂.j) : q₁ = q₂
begin cases q₁, cases q₂, congr', rw [←q₁_i_mul_j, ←q₂_i_mul_j], congr' end
lemma
quaternion_algebra.basis.ext
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "basis" ]
Since `k` is redundant, it is not necessary to show `q₁.k = q₂.k` when showing `q₁ = q₂`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
self : basis ℍ[R,c₁,c₂] c₁ c₂
{ i := ⟨0, 1, 0, 0⟩, i_mul_i := by { ext; simp }, j := ⟨0, 0, 1, 0⟩, j_mul_j := by { ext; simp }, k := ⟨0, 0, 0, 1⟩, i_mul_j := by { ext; simp }, j_mul_i := by { ext; simp } }
def
quaternion_algebra.basis.self
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "basis" ]
There is a natural quaternionic basis for the `quaternion_algebra`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
i_mul_k : q.i * q.k = c₁ • q.j
by rw [←i_mul_j, ←mul_assoc, i_mul_i, smul_mul_assoc, one_mul]
lemma
quaternion_algebra.basis.i_mul_k
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "one_mul", "smul_mul_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
k_mul_i : q.k * q.i = -c₁ • q.j
by rw [←i_mul_j, mul_assoc, j_mul_i, mul_neg, i_mul_k, neg_smul]
lemma
quaternion_algebra.basis.k_mul_i
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "mul_assoc", "mul_neg", "neg_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
k_mul_j : q.k * q.j = c₂ • q.i
by rw [←i_mul_j, mul_assoc, j_mul_j, mul_smul_comm, mul_one]
lemma
quaternion_algebra.basis.k_mul_j
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "mul_assoc", "mul_one", "mul_smul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
j_mul_k : q.j * q.k = -c₂ • q.i
by rw [←i_mul_j, ←mul_assoc, j_mul_i, neg_mul, k_mul_j, neg_smul]
lemma
quaternion_algebra.basis.j_mul_k
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "neg_mul", "neg_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
k_mul_k : q.k * q.k = -((c₁ * c₂) • 1)
by rw [←i_mul_j, mul_assoc, ←mul_assoc q.j _ _, j_mul_i, ←i_mul_j, ←mul_assoc, mul_neg, ←mul_assoc, i_mul_i, smul_mul_assoc, one_mul, neg_mul, smul_mul_assoc, j_mul_j, smul_smul]
lemma
quaternion_algebra.basis.k_mul_k
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "mul_assoc", "mul_neg", "neg_mul", "one_mul", "smul_mul_assoc", "smul_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift (x : ℍ[R,c₁,c₂]) : A
algebra_map R _ x.re + x.im_i • q.i + x.im_j • q.j + x.im_k • q.k
def
quaternion_algebra.basis.lift
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "algebra_map", "lift" ]
Intermediate result used to define `quaternion_algebra.basis.lift_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_zero : q.lift (0 : ℍ[R,c₁,c₂]) = 0
by simp [lift]
lemma
quaternion_algebra.basis.lift_zero
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_one : q.lift (1 : ℍ[R,c₁,c₂]) = 1
by simp [lift]
lemma
quaternion_algebra.basis.lift_one
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_add (x y : ℍ[R,c₁,c₂]) : q.lift (x + y) = q.lift x + q.lift y
by { simp [lift, add_smul], abel }
lemma
quaternion_algebra.basis.lift_add
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "add_smul", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_mul (x y : ℍ[R,c₁,c₂]) : q.lift (x * y) = q.lift x * q.lift y
begin simp only [lift, algebra.algebra_map_eq_smul_one], simp only [add_mul], simp only [add_mul, mul_add, smul_mul_assoc, mul_smul_comm, one_mul, mul_one, ←algebra.smul_def, smul_add, smul_smul], simp only [i_mul_i, j_mul_j, i_mul_j, j_mul_i, i_mul_k, k_mul_i, k_mul_j, j_mul_k, k_mul_k], simp only [smul_...
lemma
quaternion_algebra.basis.lift_mul
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "add_smul", "algebra.algebra_map_eq_smul_one", "lift", "mul_comm", "mul_neg", "mul_one", "mul_right_comm", "mul_smul_comm", "neg_smul", "one_mul", "smul_add", "smul_mul_assoc", "smul_neg", "smul_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_smul (r : R) (x : ℍ[R,c₁,c₂]) : q.lift (r • x) = r • q.lift x
by simp [lift, mul_smul, ←algebra.smul_def]
lemma
quaternion_algebra.basis.lift_smul
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_hom : ℍ[R,c₁,c₂] →ₐ[R] A
alg_hom.mk' { to_fun := q.lift, map_zero' := q.lift_zero, map_one' := q.lift_one, map_add' := q.lift_add, map_mul' := q.lift_mul } q.lift_smul
def
quaternion_algebra.basis.lift_hom
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "alg_hom.mk'" ]
A `quaternion_algebra.basis` implies an `alg_hom` from the quaternions.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_hom (F : A →ₐ[R] B) : basis B c₁ c₂
{ i := F q.i, i_mul_i := by rw [←F.map_mul, q.i_mul_i, F.map_smul, F.map_one], j := F q.j, j_mul_j := by rw [←F.map_mul, q.j_mul_j, F.map_smul, F.map_one], k := F q.k, i_mul_j := by rw [←F.map_mul, q.i_mul_j], j_mul_i := by rw [←F.map_mul, q.j_mul_i, F.map_neg], }
def
quaternion_algebra.basis.comp_hom
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "basis" ]
Transform a `quaternion_algebra.basis` through an `alg_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift : basis A c₁ c₂ ≃ (ℍ[R,c₁,c₂] →ₐ[R] A)
{ to_fun := basis.lift_hom, inv_fun := (basis.self R).comp_hom, left_inv := λ q, begin ext; simp [basis.lift], end, right_inv := λ F, begin ext, dsimp [basis.lift], rw ←F.commutes, simp only [←F.commutes, ←F.map_smul, ←F.map_add, mk_add_mk, smul_mk, smul_zero, algebra_map_eq], congr,...
def
quaternion_algebra.lift
algebra
src/algebra/quaternion_basis.lean
[ "algebra.quaternion", "tactic.ring" ]
[ "basis", "inv_fun", "lift", "smul_zero" ]
A quaternionic basis on `A` is equivalent to a map from the quaternion algebra to `A`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_quotient (A : out_param $ Type u) (B : Type v)
(quotient' : B → Type (max u v))
class
has_quotient
algebra
src/algebra/quotient.lean
[ "tactic.basic" ]
[]
`has_quotient A B` is a notation typeclass that allows us to write `A ⧸ b` for `b : B`. This allows the usual notation for quotients of algebraic structures, such as groups, modules and rings. `A` is a parameter, despite being unused in the definition below, so it appears in the notation.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_quotient.quotient (A : out_param $ Type u) {B : Type v} [has_quotient A B] (b : B) : Type (max u v)
has_quotient.quotient' b
def
has_quotient.quotient
algebra
src/algebra/quotient.lean
[ "tactic.basic" ]
[ "has_quotient" ]
`has_quotient.quotient A b` (with notation `A ⧸ b`) is the quotient of the type `A` by `b`. This differs from `has_quotient.quotient'` in that the `A` argument is explicit, which is necessary to make Lean show the notation in the goal state.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_algebra_map (c : ring_con A) (s : S) : (↑(algebra_map S A s) : c.quotient) = algebra_map S _ s
rfl
lemma
ring_con.coe_algebra_map
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "algebra_map", "ring_con" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel (r : R → R → Prop) : R → R → Prop | of ⦃x y : R⦄ (h : r x y) : rel x y | add_left ⦃a b c⦄ : rel a b → rel (a + c) (b + c) | mul_left ⦃a b c⦄ : rel a b → rel (a * c) (b * c) | mul_right ⦃a b c⦄ : rel b c → rel (a * b) (a * c)
inductive
ring_quot.rel
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "rel" ]
Given an arbitrary relation `r` on a ring, we strengthen it to a relation `rel r`, such that the equivalence relation generated by `rel r` has `x ~ y` if and only if `x - y` is in the ideal generated by elements `a - b` such that `r a b`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel.add_right {r : R → R → Prop} ⦃a b c : R⦄ (h : rel r b c) : rel r (a + b) (a + c)
by { rw [add_comm a b, add_comm a c], exact rel.add_left h }
theorem
ring_quot.rel.add_right
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel.neg {R : Type u₁} [ring R] {r : R → R → Prop} ⦃a b : R⦄ (h : rel r a b) : rel r (-a) (-b)
by simp only [neg_eq_neg_one_mul a, neg_eq_neg_one_mul b, rel.mul_right h]
theorem
ring_quot.rel.neg
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "neg_eq_neg_one_mul", "rel", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel.sub_left {R : Type u₁} [ring R] {r : R → R → Prop} ⦃a b c : R⦄ (h : rel r a b) : rel r (a - c) (b - c)
by simp only [sub_eq_add_neg, h.add_left]
theorem
ring_quot.rel.sub_left
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "rel", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel.sub_right {R : Type u₁} [ring R] {r : R → R → Prop} ⦃a b c : R⦄ (h : rel r b c) : rel r (a - b) (a - c)
by simp only [sub_eq_add_neg, h.neg.add_right]
theorem
ring_quot.rel.sub_right
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "rel", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel.smul {r : A → A → Prop} (k : S) ⦃a b : A⦄ (h : rel r a b) : rel r (k • a) (k • b)
by simp only [algebra.smul_def, rel.mul_right h]
theorem
ring_quot.rel.smul
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "algebra.smul_def", "rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_con (r : R → R → Prop) : ring_con R
{ r := eqv_gen (rel r), iseqv := eqv_gen.is_equivalence _, add' := λ a b c d hab hcd, begin induction hab with a' b' hab e a' b' hab' _ c' d' e hcd' hde' ihcd' ihde' generalizing c d, { refine (eqv_gen.rel _ _ hab.add_left).trans _ _ _ _, induction hcd with c' d' hcd f c' d' hcd' habcd' c' d' f' hcd' ...
def
ring_quot.ring_con
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "rel", "ring_con" ]
`eqv_gen (ring_quot.rel r)` is a ring congruence.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eqv_gen_rel_eq (r : R → R → Prop) : eqv_gen (rel r) = ring_con_gen.rel r
begin ext x₁ x₂, split, { intro h, induction h with x₃ x₄ h₃₄, { induction h₃₄ with _ dfg h₃₄ x₃ x₄ x₅ h₃₄', { exact ring_con_gen.rel.of _ _ ‹_› }, { exact h₃₄_ih.add (ring_con_gen.rel.refl _) }, { exact h₃₄_ih.mul (ring_con_gen.rel.refl _) }, { exact (ring_con_gen.rel.refl _).mul ...
lemma
ring_quot.eqv_gen_rel_eq
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "rel", "ring_con_gen.rel", "ring_quot.ring_con" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_quot (r : R → R → Prop)
(to_quot : quot (ring_quot.rel r))
structure
ring_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot.rel" ]
The quotient of a ring by an arbitrary relation.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_cast (n : ℕ) : ring_quot r
⟨quot.mk _ n⟩
def
ring_quot.nat_cast
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero : ring_quot r
⟨quot.mk _ 0⟩
def
ring_quot.zero
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one : ring_quot r
⟨quot.mk _ 1⟩
def
ring_quot.one
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add : ring_quot r → ring_quot r → ring_quot r
| ⟨a⟩ ⟨b⟩ := ⟨quot.map₂ (+) rel.add_right rel.add_left a b⟩
def
ring_quot.add
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul : ring_quot r → ring_quot r → ring_quot r
| ⟨a⟩ ⟨b⟩ := ⟨quot.map₂ (*) rel.mul_right rel.mul_left a b⟩
def
ring_quot.mul
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg {R : Type u₁} [ring R] (r : R → R → Prop) : ring_quot r → ring_quot r
| ⟨a⟩:= ⟨quot.map (λ a, -a) rel.neg a⟩
def
ring_quot.neg
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub {R : Type u₁} [ring R] (r : R → R → Prop) : ring_quot r → ring_quot r → ring_quot r
| ⟨a⟩ ⟨b⟩ := ⟨quot.map₂ has_sub.sub rel.sub_right rel.sub_left a b⟩
def
ring_quot.sub
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
npow (n : ℕ) : ring_quot r → ring_quot r
| ⟨a⟩ := ⟨quot.lift (λ a, quot.mk (ring_quot.rel r) (a ^ n)) (λ a b (h : rel r a b), begin -- note we can't define a `rel.pow` as `rel` isn't reflexive so `rel r 1 1` isn't true dsimp only, induction n, { rw [pow_zero, pow_zero] }, { rw [po...
def
ring_quot.npow
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "congr_arg2", "pow_succ", "pow_zero", "rel", "ring_quot", "ring_quot.rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul [algebra S R] (n : S) : ring_quot r → ring_quot r
| ⟨a⟩ := ⟨quot.map (λ a, n • a) (rel.smul n) a⟩
def
ring_quot.smul
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "algebra", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_quot : (⟨quot.mk _ 0⟩ : ring_quot r) = 0
show _ = zero r, by rw zero
lemma
ring_quot.zero_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_quot : (⟨quot.mk _ 1⟩ : ring_quot r) = 1
show _ = one r, by rw one
lemma
ring_quot.one_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_quot {a b} : (⟨quot.mk _ a⟩ + ⟨quot.mk _ b⟩ : ring_quot r) = ⟨quot.mk _ (a + b)⟩
by { show add r _ _ = _, rw add, refl }
lemma
ring_quot.add_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_quot {a b} : (⟨quot.mk _ a⟩ * ⟨quot.mk _ b⟩ : ring_quot r) = ⟨quot.mk _ (a * b)⟩
by { show mul r _ _ = _, rw mul, refl }
lemma
ring_quot.mul_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_quot {a} {n : ℕ}: (⟨quot.mk _ a⟩ ^ n : ring_quot r) = ⟨quot.mk _ (a ^ n)⟩
by { show npow r _ _ = _, rw npow }
lemma
ring_quot.pow_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_quot {R : Type u₁} [ring R] (r : R → R → Prop) {a} : (-⟨quot.mk _ a⟩ : ring_quot r) = ⟨quot.mk _ (-a)⟩
by { show neg r _ = _, rw neg, refl }
lemma
ring_quot.neg_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_quot {R : Type u₁} [ring R] (r : R → R → Prop) {a b} : (⟨quot.mk _ a⟩ - ⟨ quot.mk _ b⟩ : ring_quot r) = ⟨quot.mk _ (a - b)⟩
by { show sub r _ _ = _, rw sub, refl }
lemma
ring_quot.sub_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_quot [algebra S R] {n : S} {a : R} : (n • ⟨quot.mk _ a⟩ : ring_quot r) = ⟨quot.mk _ (n • a)⟩
by { show smul r _ _ = _, rw smul, refl }
lemma
ring_quot.smul_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "algebra", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_ring_hom (r : R → R → Prop) : R →+* ring_quot r
{ to_fun := λ x, ⟨quot.mk _ x⟩, map_one' := by simp [← one_quot], map_mul' := by simp [mul_quot], map_zero' := by simp [← zero_quot], map_add' := by simp [add_quot], }
def
ring_quot.mk_ring_hom
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
The quotient map from a ring to its quotient, as a homomorphism of rings.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_ring_hom_rel {r : R → R → Prop} {x y : R} (w : r x y) : mk_ring_hom r x = mk_ring_hom r y
by simp [mk_ring_hom, quot.sound (rel.of w)]
lemma
ring_quot.mk_ring_hom_rel
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_ring_hom_surjective (r : R → R → Prop) : function.surjective (mk_ring_hom r)
by { dsimp [mk_ring_hom], rintro ⟨⟨⟩⟩, simp, }
lemma
ring_quot.mk_ring_hom_surjective
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_quot_ext {T : Type u₄} [semiring T] {r : R → R → Prop} (f g : ring_quot r →+* T) (w : f.comp (mk_ring_hom r) = g.comp (mk_ring_hom r)) : f = g
begin ext, rcases mk_ring_hom_surjective r x with ⟨x, rfl⟩, exact (ring_hom.congr_fun w x : _), end
lemma
ring_quot.ring_quot_ext
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_hom.congr_fun", "ring_quot", "semiring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift {r : R → R → Prop} : {f : R →+* T // ∀ ⦃x y⦄, r x y → f x = f y} ≃ (ring_quot r →+* T)
{ to_fun := λ f', let f := (f' : R →+* T) in { to_fun := λ x, quot.lift f begin rintros _ _ r, induction r, case of : _ _ r { exact f'.prop r, }, case add_left : _ _ _ _ r' { simp [r'], }, case mul_left : _ _ _ _ r' { simp [r'], }, case mul_right : _ _ _ _ r' { simp [r'], },
def
ring_quot.lift
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "lift", "ring_quot" ]
Any ring homomorphism `f : R →+* T` which respects a relation `r : R → R → Prop` factors uniquely through a morphism `ring_quot r →+* T`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_mk_ring_hom_apply (f : R →+* T) {r : R → R → Prop} (w : ∀ ⦃x y⦄, r x y → f x = f y) (x) : lift ⟨f, w⟩ (mk_ring_hom r x) = f x
by { simp_rw [lift, mk_ring_hom], refl }
lemma
lift_mk_ring_hom_apply
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_unique (f : R →+* T) {r : R → R → Prop} (w : ∀ ⦃x y⦄, r x y → f x = f y) (g : ring_quot r →+* T) (h : g.comp (mk_ring_hom r) = f) : g = lift ⟨f, w⟩
by { ext, simp [h], }
lemma
lift_unique
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "lift", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_lift_comp_mk_ring_hom {r : R → R → Prop} (f : ring_quot r →+* T) : f = lift ⟨f.comp (mk_ring_hom r), λ x y h, by { dsimp, rw mk_ring_hom_rel h, }⟩
begin conv_lhs { rw ← lift.apply_symm_apply f }, rw lift, refl, end
lemma
eq_lift_comp_mk_ring_hom
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "lift", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_quot_to_ideal_quotient (r : B → B → Prop) : ring_quot r →+* B ⧸ ideal.of_rel r
lift ⟨ideal.quotient.mk (ideal.of_rel r), λ x y h, ideal.quotient.eq.2 $ submodule.mem_Inf.mpr (λ p w, w ⟨x, y, h, sub_add_cancel x y⟩)⟩
def
ring_quot_to_ideal_quotient
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ideal.of_rel", "lift", "ring_quot" ]
The universal ring homomorphism from `ring_quot r` to `B ⧸ ideal.of_rel r`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_quot_to_ideal_quotient_apply (r : B → B → Prop) (x : B) : ring_quot_to_ideal_quotient r (mk_ring_hom r x) = ideal.quotient.mk _ x
begin simp_rw [ring_quot_to_ideal_quotient, lift, mk_ring_hom], refl end
lemma
ring_quot_to_ideal_quotient_apply
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.mk", "lift", "ring_quot_to_ideal_quotient" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal_quotient_to_ring_quot (r : B → B → Prop) : B ⧸ ideal.of_rel r →+* ring_quot r
ideal.quotient.lift (ideal.of_rel r) (mk_ring_hom r) begin refine λ x h, submodule.span_induction h _ _ _ _, { rintro y ⟨a, b, h, su⟩, symmetry' at su, rw ←sub_eq_iff_eq_add at su, rw [ ← su, ring_hom.map_sub, mk_ring_hom_rel h, sub_self], }, { simp, }, { intros a b ha hb, simp [ha, hb], }, { intr...
def
ideal_quotient_to_ring_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ideal.of_rel", "ideal.quotient.lift", "ring_hom.map_sub", "ring_quot", "submodule.span_induction" ]
The universal ring homomorphism from `B ⧸ ideal.of_rel r` to `ring_quot r`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal_quotient_to_ring_quot_apply (r : B → B → Prop) (x : B) : ideal_quotient_to_ring_quot r (ideal.quotient.mk _ x) = mk_ring_hom r x
rfl
lemma
ideal_quotient_to_ring_quot_apply
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.mk", "ideal_quotient_to_ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_quot_equiv_ideal_quotient (r : B → B → Prop) : ring_quot r ≃+* B ⧸ ideal.of_rel r
ring_equiv.of_hom_inv (ring_quot_to_ideal_quotient r) (ideal_quotient_to_ring_quot r) (begin ext, simp_rw [ring_quot_to_ideal_quotient, lift, mk_ring_hom], dsimp, rw [mk_ring_hom], refl end) (begin ext, simp_rw [ring_quot_to_ideal_quotient, lift, mk_ring_hom], dsimp, rw [mk_rin...
def
ring_quot_equiv_ideal_quotient
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ideal.of_rel", "ideal_quotient_to_ring_quot", "lift", "ring_equiv.of_hom_inv", "ring_quot", "ring_quot_to_ideal_quotient" ]
The ring equivalence between `ring_quot r` and `(ideal.of_rel r).quotient`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel.star ⦃a b : R⦄ (h : rel r a b) : rel r (star a) (star b)
begin induction h, { exact rel.of (hr _ _ h_h) }, { rw [star_add, star_add], exact rel.add_left h_ih, }, { rw [star_mul, star_mul], exact rel.mul_right h_ih, }, { rw [star_mul, star_mul], exact rel.mul_left h_ih, }, end
theorem
rel.star
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
star' : ring_quot r → ring_quot r
| ⟨a⟩ := ⟨quot.map (star : R → R) (rel.star r hr) a⟩
def
star'
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "rel.star", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
star'_quot (hr : ∀ a b, r a b → r (star a) (star b)) {a} : (star' r hr ⟨quot.mk _ a⟩ : ring_quot r) = ⟨quot.mk _ (star a)⟩
by { show star' r _ _ = _, rw star', refl }
lemma
star'_quot
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot", "star'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
star_ring {R : Type u₁} [semiring R] [star_ring R] (r : R → R → Prop) (hr : ∀ a b, r a b → r (star a) (star b)) : star_ring (ring_quot r)
{ star := star' r hr, star_involutive := by { rintros ⟨⟨⟩⟩, simp [star'_quot], }, star_mul := by { rintros ⟨⟨⟩⟩ ⟨⟨⟩⟩, simp [star'_quot, mul_quot, star_mul], }, star_add := by { rintros ⟨⟨⟩⟩ ⟨⟨⟩⟩, simp [star'_quot, add_quot, star_add], } }
def
star_ring
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot", "semiring", "star'", "star'_quot" ]
Transfer a star_ring instance through a quotient, if the quotient is invariant to `star`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_alg_hom (s : A → A → Prop) : A →ₐ[S] ring_quot s
{ commutes' := λ r, by { simp [mk_ring_hom], refl }, ..mk_ring_hom s }
def
mk_alg_hom
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
The quotient map from an `S`-algebra to its quotient, as a homomorphism of `S`-algebras.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_alg_hom_coe (s : A → A → Prop) : (mk_alg_hom S s : A →+* ring_quot s) = mk_ring_hom s
by { simp_rw [mk_alg_hom, mk_ring_hom], refl }
lemma
mk_alg_hom_coe
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "mk_alg_hom", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_alg_hom_rel {s : A → A → Prop} {x y : A} (w : s x y) : mk_alg_hom S s x = mk_alg_hom S s y
by simp [mk_alg_hom, mk_ring_hom, quot.sound (rel.of w)]
lemma
mk_alg_hom_rel
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "mk_alg_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_alg_hom_surjective (s : A → A → Prop) : function.surjective (mk_alg_hom S s)
by { dsimp [mk_alg_hom, mk_ring_hom], rintro ⟨⟨a⟩⟩, use a, refl, }
lemma
mk_alg_hom_surjective
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "mk_alg_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_quot_ext' {s : A → A → Prop} (f g : ring_quot s →ₐ[S] B) (w : f.comp (mk_alg_hom S s) = g.comp (mk_alg_hom S s)) : f = g
begin ext, rcases mk_alg_hom_surjective S s x with ⟨x, rfl⟩, exact (alg_hom.congr_fun w x : _), end
lemma
ring_quot_ext'
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "alg_hom.congr_fun", "mk_alg_hom", "mk_alg_hom_surjective", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_alg_hom {s : A → A → Prop} : {f : A →ₐ[S] B // ∀ ⦃x y⦄, s x y → f x = f y} ≃ (ring_quot s →ₐ[S] B)
{ to_fun := λ f', let f := (f' : A →ₐ[S] B) in { to_fun := λ x, quot.lift f begin rintros _ _ r, induction r, case of : _ _ r { exact f'.prop r, }, case add_left : _ _ _ _ r' { simp [r'], }, case mul_left : _ _ _ _ r' { simp [r'], }, case mul_right : _ _ _ _ r' { simp [r'], },
def
lift_alg_hom
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "ring_quot" ]
Any `S`-algebra homomorphism `f : A →ₐ[S] B` which respects a relation `s : A → A → Prop` factors uniquely through a morphism `ring_quot s →ₐ[S] B`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_alg_hom_mk_alg_hom_apply (f : A →ₐ[S] B) {s : A → A → Prop} (w : ∀ ⦃x y⦄, s x y → f x = f y) (x) : (lift_alg_hom S ⟨f, w⟩) ((mk_alg_hom S s) x) = f x
by { simp_rw [lift_alg_hom, mk_alg_hom, mk_ring_hom], refl, }
lemma
lift_alg_hom_mk_alg_hom_apply
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "lift_alg_hom", "mk_alg_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_alg_hom_unique (f : A →ₐ[S] B) {s : A → A → Prop} (w : ∀ ⦃x y⦄, s x y → f x = f y) (g : ring_quot s →ₐ[S] B) (h : g.comp (mk_alg_hom S s) = f) : g = lift_alg_hom S ⟨f, w⟩
by { ext, simp [h], }
lemma
lift_alg_hom_unique
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "lift_alg_hom", "mk_alg_hom", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_lift_alg_hom_comp_mk_alg_hom {s : A → A → Prop} (f : ring_quot s →ₐ[S] B) : f = lift_alg_hom S ⟨f.comp (mk_alg_hom S s), λ x y h, by { dsimp, erw mk_alg_hom_rel S h, }⟩
begin conv_lhs { rw ← ((lift_alg_hom S).apply_symm_apply f) }, rw lift_alg_hom, refl, end
lemma
eq_lift_alg_hom_comp_mk_alg_hom
algebra
src/algebra/ring_quot.lean
[ "algebra.algebra.hom", "ring_theory.ideal.quotient" ]
[ "lift_alg_hom", "mk_alg_hom", "mk_alg_hom_rel", "ring_quot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_with_zero [has_zero R] [has_zero M] extends smul_zero_class R M
(zero_smul : ∀ m : M, (0 : R) • m = 0)
class
smul_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "smul_zero_class", "zero_smul" ]
`smul_with_zero` is a class consisting of a Type `R` with `0 ∈ R` and a scalar multiplication of `R` on a Type `M` with `0`, such that the equality `r • m = 0` holds if at least one among `r` or `m` equals `0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_zero_class.to_smul_with_zero [mul_zero_class R] : smul_with_zero R R
{ smul := (*), smul_zero := mul_zero, zero_smul := zero_mul }
instance
mul_zero_class.to_smul_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "mul_zero", "mul_zero_class", "smul_with_zero", "smul_zero", "zero_mul", "zero_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_zero_class.to_opposite_smul_with_zero [mul_zero_class R] : smul_with_zero Rᵐᵒᵖ R
{ smul := (•), smul_zero := λ r, zero_mul _, zero_smul := mul_zero }
instance
mul_zero_class.to_opposite_smul_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "mul_zero", "mul_zero_class", "smul_with_zero", "smul_zero", "zero_mul", "zero_smul" ]
Like `mul_zero_class.to_smul_with_zero`, but multiplies on the right.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_smul (m : M) : (0 : R) • m = 0
smul_with_zero.zero_smul m
lemma
zero_smul
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_eq_zero_of_left (h : a = 0) (b : M) : a • b = 0
h.symm ▸ zero_smul _ b
lemma
smul_eq_zero_of_left
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "zero_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_eq_zero_of_right (a : R) (h : b = 0) : a • b = 0
h.symm ▸ smul_zero a
lemma
smul_eq_zero_of_right
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "smul_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_ne_zero_of_smul : a • b ≠ 0 → a ≠ 0
mt $ λ h, smul_eq_zero_of_left h b
lemma
left_ne_zero_of_smul
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "smul_eq_zero_of_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
right_ne_zero_of_smul : a • b ≠ 0 → b ≠ 0
mt $ smul_eq_zero_of_right a
lemma
right_ne_zero_of_smul
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "smul_eq_zero_of_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
function.injective.smul_with_zero (f : zero_hom M' M) (hf : function.injective f) (smul : ∀ (a : R) b, f (a • b) = a • f b) : smul_with_zero R M'
{ smul := (•), zero_smul := λ a, hf $ by simp [smul], smul_zero := λ a, hf $ by simp [smul]}
def
function.injective.smul_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "smul_with_zero", "smul_zero", "zero_hom", "zero_smul" ]
Pullback a `smul_with_zero` structure along an injective zero-preserving homomorphism. See note [reducible non-instances].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
function.surjective.smul_with_zero (f : zero_hom M M') (hf : function.surjective f) (smul : ∀ (a : R) b, f (a • b) = a • f b) : smul_with_zero R M'
{ smul := (•), zero_smul := λ m, by { rcases hf m with ⟨x, rfl⟩, simp [←smul] }, smul_zero := λ c, by simp only [← f.map_zero, ← smul, smul_zero] }
def
function.surjective.smul_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "smul_with_zero", "smul_zero", "zero_hom", "zero_smul" ]
Pushforward a `smul_with_zero` structure along a surjective zero-preserving homomorphism. See note [reducible non-instances].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_with_zero.comp_hom (f : zero_hom R' R) : smul_with_zero R' M
{ smul := (•) ∘ f, smul_zero := λ m, by simp, zero_smul := λ m, by simp }
def
smul_with_zero.comp_hom
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "smul_with_zero", "smul_zero", "zero_hom", "zero_smul" ]
Compose a `smul_with_zero` with a `zero_hom`, with action `f r' • m`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_monoid.nat_smul_with_zero [add_monoid M] : smul_with_zero ℕ M
{ smul_zero := nsmul_zero, zero_smul := zero_nsmul }
instance
add_monoid.nat_smul_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "add_monoid", "smul_with_zero", "smul_zero", "zero_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_group.int_smul_with_zero [add_group M] : smul_with_zero ℤ M
{ smul_zero := zsmul_zero, zero_smul := zero_zsmul }
instance
add_group.int_smul_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "add_group", "smul_with_zero", "smul_zero", "zero_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_action_with_zero extends mul_action R M
-- these fields are copied from `smul_with_zero`, as `extends` behaves poorly (smul_zero : ∀ r : R, r • (0 : M) = 0) (zero_smul : ∀ m : M, (0 : R) • m = 0)
class
mul_action_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "mul_action", "smul_zero", "zero_smul" ]
An action of a monoid with zero `R` on a Type `M`, also with `0`, extends `mul_action` and is compatible with `0` (both in `R` and in `M`), with `1 ∈ R`, and with associativity of multiplication on the monoid `M`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_action_with_zero.to_smul_with_zero [m : mul_action_with_zero R M] : smul_with_zero R M
{..m}
instance
mul_action_with_zero.to_smul_with_zero
algebra
src/algebra/smul_with_zero.lean
[ "algebra.group_power.basic", "algebra.ring.opposite", "group_theory.group_action.opposite", "group_theory.group_action.prod" ]
[ "mul_action_with_zero", "smul_with_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83