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quotient_map_surjective {J : ideal R} {I : ideal S} {f : R →+* S} {H : J ≤ I.comap f} (hf : function.surjective f) : function.surjective (quotient_map I f H)
λ x, let ⟨x, hx⟩ := quotient.mk_surjective x in let ⟨y, hy⟩ := hf x in ⟨(quotient.mk J) y, by simp [hx, hy]⟩
lemma
ideal.quotient_map_surjective
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal", "quotient_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_quotient_map_eq_of_comp_eq {R' S' : Type*} [comm_ring R'] [comm_ring S'] {f : R →+* S} {f' : R' →+* S'} {g : R →+* R'} {g' : S →+* S'} (hfg : f'.comp g = g'.comp f) (I : ideal S') : (quotient_map I g' le_rfl).comp (quotient_map (I.comap g') f le_rfl) = (quotient_map I f' le_rfl).comp (quotient_map (I.comap...
begin refine ring_hom.ext (λ a, _), obtain ⟨r, rfl⟩ := quotient.mk_surjective a, simp only [ring_hom.comp_apply, quotient_map_mk], exact congr_arg (quotient.mk I) (trans (g'.comp_apply f r).symm (hfg ▸ (f'.comp_apply g r))), end
lemma
ideal.comp_quotient_map_eq_of_comp_eq
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "comm_ring", "ideal", "le_rfl", "quotient_map", "ring_hom.comp_apply", "ring_hom.ext" ]
Commutativity of a square is preserved when taking quotients by an ideal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_mapₐ {I : ideal A} (J : ideal B) (f : A →ₐ[R₁] B) (hIJ : I ≤ J.comap f) : A ⧸ I →ₐ[R₁] B ⧸ J
{ commutes' := λ r, by simp, ..quotient_map J (f : A →+* B) hIJ }
def
ideal.quotient_mapₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal", "quotient_map" ]
The algebra hom `A/I →+* B/J` induced by an algebra hom `f : A →ₐ[R₁] B` with `I ≤ f⁻¹(J)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_map_mkₐ {I : ideal A} (J : ideal B) (f : A →ₐ[R₁] B) (H : I ≤ J.comap f) {x : A} : quotient_mapₐ J f H (quotient.mk I x) = quotient.mkₐ R₁ J (f x)
rfl
lemma
ideal.quotient_map_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_map_comp_mkₐ {I : ideal A} (J : ideal B) (f : A →ₐ[R₁] B) (H : I ≤ J.comap f) : (quotient_mapₐ J f H).comp (quotient.mkₐ R₁ I) = (quotient.mkₐ R₁ J).comp f
alg_hom.ext (λ x, by simp only [quotient_map_mkₐ, quotient.mkₐ_eq_mk, alg_hom.comp_apply])
lemma
ideal.quotient_map_comp_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_hom.comp_apply", "alg_hom.ext", "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_equiv_alg (I : ideal A) (J : ideal B) (f : A ≃ₐ[R₁] B) (hIJ : J = I.map (f : A →+* B)) : (A ⧸ I) ≃ₐ[R₁] B ⧸ J
{ commutes' := λ r, by simp, ..quotient_equiv I J (f : A ≃+* B) hIJ }
def
ideal.quotient_equiv_alg
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal" ]
The algebra equiv `A/I ≃ₐ[R] B/J` induced by an algebra equiv `f : A ≃ₐ[R] B`, where`J = f(I)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_algebra {I : ideal A} [algebra R A] : algebra (R ⧸ I.comap (algebra_map R A)) (A ⧸ I)
(quotient_map I (algebra_map R A) (le_of_eq rfl)).to_algebra
instance
ideal.quotient_algebra
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "algebra", "algebra_map", "ideal", "quotient_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_quotient_injective {I : ideal A} [algebra R A]: function.injective (algebra_map (R ⧸ I.comap (algebra_map R A)) (A ⧸ I))
begin rintros ⟨a⟩ ⟨b⟩ hab, replace hab := quotient.eq.mp hab, rw ← ring_hom.map_sub at hab, exact quotient.eq.mpr hab end
lemma
ideal.algebra_map_quotient_injective
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "algebra", "algebra_map", "ideal", "ring_hom.map_sub" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_equiv_alg_of_eq {I J : ideal A} (h : I = J) : (A ⧸ I) ≃ₐ[R₁] A ⧸ J
quotient_equiv_alg I J alg_equiv.refl $ h ▸ (map_id I).symm
def
ideal.quotient_equiv_alg_of_eq
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_equiv.refl", "ideal", "map_id" ]
Quotienting by equal ideals gives equivalent algebras.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_equiv_alg_of_eq_mk {I J : ideal A} (h : I = J) (x : A) : quotient_equiv_alg_of_eq R₁ h (ideal.quotient.mk I x) = ideal.quotient.mk J x
rfl
lemma
ideal.quotient_equiv_alg_of_eq_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal", "ideal.quotient.mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_equiv_alg_of_eq_symm {I J : ideal A} (h : I = J) : (quotient_equiv_alg_of_eq R₁ h).symm = quotient_equiv_alg_of_eq R₁ h.symm
by ext; refl
lemma
ideal.quotient_equiv_alg_of_eq_symm
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_left_to_quot_sup : R ⧸ I →+* R ⧸ (I ⊔ J)
ideal.quotient.factor I (I ⊔ J) le_sup_left
def
double_quot.quot_left_to_quot_sup
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.factor", "le_sup_left" ]
The obvious ring hom `R/I → R/(I ⊔ J)`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ker_quot_left_to_quot_sup : (quot_left_to_quot_sup I J).ker = J.map (ideal.quotient.mk I)
by simp only [mk_ker, sup_idem, sup_comm, quot_left_to_quot_sup, quotient.factor, ker_quotient_lift, map_eq_iff_sup_ker_eq_of_surjective I^.quotient.mk quotient.mk_surjective, ← sup_assoc]
lemma
double_quot.ker_quot_left_to_quot_sup
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.mk", "sup_assoc", "sup_comm", "sup_idem" ]
The kernel of `quot_left_to_quot_sup`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_to_quot_sup : (R ⧸ I) ⧸ J.map (ideal.quotient.mk I) →+* R ⧸ I ⊔ J
by exact ideal.quotient.lift (J.map (ideal.quotient.mk I)) (quot_left_to_quot_sup I J) (ker_quot_left_to_quot_sup I J).symm.le
def
double_quot.quot_quot_to_quot_sup
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.lift", "ideal.quotient.mk" ]
The ring homomorphism `(R/I)/J' -> R/(I ⊔ J)` induced by `quot_left_to_quot_sup` where `J'` is the image of `J` in `R/I`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_mk : R →+* ((R ⧸ I) ⧸ J.map I^.quotient.mk)
by exact ((J.map I^.quotient.mk)^.quotient.mk).comp I^.quotient.mk
def
double_quot.quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
The composite of the maps `R → (R/I)` and `(R/I) → (R/I)/J'`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ker_quot_quot_mk : (quot_quot_mk I J).ker = I ⊔ J
by rw [ring_hom.ker_eq_comap_bot, quot_quot_mk, ← comap_comap, ← ring_hom.ker, mk_ker, comap_map_of_surjective (ideal.quotient.mk I) (quotient.mk_surjective), ← ring_hom.ker, mk_ker, sup_comm]
lemma
double_quot.ker_quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.mk", "ring_hom.ker", "ring_hom.ker_eq_comap_bot", "sup_comm" ]
The kernel of `quot_quot_mk`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_sup_quot_quot_mk (I J : ideal R) : R ⧸ (I ⊔ J) →+* (R ⧸ I) ⧸ J.map (ideal.quotient.mk I)
ideal.quotient.lift (I ⊔ J) (quot_quot_mk I J) (ker_quot_quot_mk I J).symm.le
def
double_quot.lift_sup_quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal", "ideal.quotient.lift", "ideal.quotient.mk" ]
The ring homomorphism `R/(I ⊔ J) → (R/I)/J' `induced by `quot_quot_mk`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_sup : (R ⧸ I) ⧸ J.map (ideal.quotient.mk I) ≃+* R ⧸ I ⊔ J
ring_equiv.of_hom_inv (quot_quot_to_quot_sup I J) (lift_sup_quot_quot_mk I J) (by { ext z, refl }) (by { ext z, refl })
def
double_quot.quot_quot_equiv_quot_sup
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.mk", "ring_equiv.of_hom_inv" ]
`quot_quot_to_quot_add` and `lift_sup_double_qot_mk` are inverse isomorphisms. In the case where `I ≤ J`, this is the Third Isomorphism Theorem (see `quot_quot_equiv_quot_of_le`)
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_sup_quot_quot_mk (x : R) : quot_quot_equiv_quot_sup I J (quot_quot_mk I J x) = ideal.quotient.mk (I ⊔ J) x
rfl
lemma
double_quot.quot_quot_equiv_quot_sup_quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_sup_symm_quot_quot_mk (x : R) : (quot_quot_equiv_quot_sup I J).symm (ideal.quotient.mk (I ⊔ J) x) = quot_quot_mk I J x
rfl
lemma
double_quot.quot_quot_equiv_quot_sup_symm_quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal.quotient.mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_comm : (R ⧸ I) ⧸ J.map I^.quotient.mk ≃+* (R ⧸ J) ⧸ I.map J^.quotient.mk
((quot_quot_equiv_quot_sup I J).trans (quot_equiv_of_eq sup_comm)).trans (quot_quot_equiv_quot_sup J I).symm
def
double_quot.quot_quot_equiv_comm
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "sup_comm" ]
The obvious isomorphism `(R/I)/J' → (R/J)/I' `
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_comm_quot_quot_mk (x : R) : quot_quot_equiv_comm I J (quot_quot_mk I J x) = quot_quot_mk J I x
rfl
lemma
double_quot.quot_quot_equiv_comm_quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_comm_comp_quot_quot_mk : ring_hom.comp ↑(quot_quot_equiv_comm I J) (quot_quot_mk I J) = quot_quot_mk J I
ring_hom.ext $ quot_quot_equiv_comm_quot_quot_mk I J
lemma
double_quot.quot_quot_equiv_comm_comp_quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ring_hom.comp", "ring_hom.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_comm_symm : (quot_quot_equiv_comm I J).symm = quot_quot_equiv_comm J I
rfl
lemma
double_quot.quot_quot_equiv_comm_symm
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_le (h : I ≤ J) : (R ⧸ I) ⧸ (J.map I^.quotient.mk) ≃+* R ⧸ J
(quot_quot_equiv_quot_sup I J).trans (ideal.quot_equiv_of_eq $ sup_eq_right.mpr h)
def
double_quot.quot_quot_equiv_quot_of_le
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal.quot_equiv_of_eq" ]
**The Third Isomorphism theorem** for rings. See `quot_quot_equiv_quot_sup` for a version that does not assume an inclusion of ideals.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_le_quot_quot_mk (x : R) (h : I ≤ J) : quot_quot_equiv_quot_of_le h (quot_quot_mk I J x) = J^.quotient.mk x
rfl
lemma
double_quot.quot_quot_equiv_quot_of_le_quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_le_symm_mk (x : R) (h : I ≤ J) : (quot_quot_equiv_quot_of_le h).symm (J^.quotient.mk x) = (quot_quot_mk I J x)
rfl
lemma
double_quot.quot_quot_equiv_quot_of_le_symm_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_le_comp_quot_quot_mk (h : I ≤ J) : ring_hom.comp ↑(quot_quot_equiv_quot_of_le h) (quot_quot_mk I J) = J^.quotient.mk
by ext ; refl
lemma
double_quot.quot_quot_equiv_quot_of_le_comp_quot_quot_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ring_hom.comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_le_symm_comp_mk (h : I ≤ J) : ring_hom.comp ↑(quot_quot_equiv_quot_of_le h).symm J^.quotient.mk = quot_quot_mk I J
by ext ; refl
lemma
double_quot.quot_quot_equiv_quot_of_le_symm_comp_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ring_hom.comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_comm_mk_mk [comm_ring R] (I J : ideal R) (x : R) : quot_quot_equiv_comm I J (ideal.quotient.mk _ (ideal.quotient.mk _ x)) = algebra_map R _ x
rfl
lemma
double_quot.quot_quot_equiv_comm_mk_mk
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "algebra_map", "comm_ring", "ideal", "ideal.quotient.mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_sup_quot_quot_algebra_map (x : R) : double_quot.quot_quot_equiv_quot_sup I J (algebra_map R _ x) = algebra_map _ _ x
rfl
lemma
double_quot.quot_quot_equiv_quot_sup_quot_quot_algebra_map
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "algebra_map", "double_quot.quot_quot_equiv_quot_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_comm_algebra_map (x : R) : quot_quot_equiv_comm I J (algebra_map R _ x) = algebra_map _ _ x
rfl
lemma
double_quot.quot_quot_equiv_comm_algebra_map
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "algebra_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_left_to_quot_supₐ : A ⧸ I →ₐ[R] A ⧸ (I ⊔ J)
alg_hom.mk (quot_left_to_quot_sup I J) rfl (map_mul _) rfl (map_add _) (λ _, rfl)
def
double_quot.quot_left_to_quot_supₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "map_mul" ]
The natural algebra homomorphism `A / I → A / (I ⊔ J)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_left_to_quot_supₐ_to_ring_hom : (quot_left_to_quot_supₐ R I J).to_ring_hom = quot_left_to_quot_sup I J
rfl
lemma
double_quot.quot_left_to_quot_supₐ_to_ring_hom
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_quot_left_to_quot_supₐ : ⇑(quot_left_to_quot_supₐ R I J) = quot_left_to_quot_sup I J
rfl
lemma
double_quot.coe_quot_left_to_quot_supₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_to_quot_supₐ : (A ⧸ I) ⧸ J.map (I^.quotient.mkₐ R) →ₐ[R] A ⧸ I ⊔ J
alg_hom.mk (quot_quot_to_quot_sup I J) rfl (map_mul _) rfl (map_add _) (λ _, rfl)
def
double_quot.quot_quot_to_quot_supₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "map_mul" ]
The algebra homomorphism `(A / I) / J' -> A / (I ⊔ J) induced by `quot_left_to_quot_sup`, where `J'` is the projection of `J` in `A / I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_to_quot_supₐ_to_ring_hom : (quot_quot_to_quot_supₐ R I J).to_ring_hom = quot_quot_to_quot_sup I J
rfl
lemma
double_quot.quot_quot_to_quot_supₐ_to_ring_hom
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_quot_quot_to_quot_supₐ : ⇑(quot_quot_to_quot_supₐ R I J) = quot_quot_to_quot_sup I J
rfl
lemma
double_quot.coe_quot_quot_to_quot_supₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_mkₐ : A →ₐ[R] ((A ⧸ I) ⧸ J.map (I^.quotient.mkₐ R))
alg_hom.mk (quot_quot_mk I J) rfl (map_mul _) rfl (map_add _) (λ _, rfl)
def
double_quot.quot_quot_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "map_mul" ]
The composition of the algebra homomorphisms `A → (A / I)` and `(A / I) → (A / I) / J'`, where `J'` is the projection `J` in `A / I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_mkₐ_to_ring_hom : (quot_quot_mkₐ R I J).to_ring_hom = quot_quot_mk I J
rfl
lemma
double_quot.quot_quot_mkₐ_to_ring_hom
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_quot_quot_mkₐ : ⇑(quot_quot_mkₐ R I J) = quot_quot_mk I J
rfl
lemma
double_quot.coe_quot_quot_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_sup_quot_quot_mkₐ (I J : ideal A) : A ⧸ (I ⊔ J) →ₐ[R] (A ⧸ I) ⧸ J.map (I^.quotient.mkₐ R)
alg_hom.mk (lift_sup_quot_quot_mk I J) rfl (map_mul _) rfl (map_add _) (λ _, rfl)
def
double_quot.lift_sup_quot_quot_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "ideal", "map_mul" ]
The injective algebra homomorphism `A / (I ⊔ J) → (A / I) / J'`induced by `quot_quot_mk`, where `J'` is the projection `J` in `A / I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_sup_quot_quot_mkₐ_to_ring_hom : (lift_sup_quot_quot_mkₐ R I J).to_ring_hom = lift_sup_quot_quot_mk I J
rfl
lemma
double_quot.lift_sup_quot_quot_mkₐ_to_ring_hom
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_lift_sup_quot_quot_mkₐ : ⇑(lift_sup_quot_quot_mkₐ R I J) = lift_sup_quot_quot_mk I J
rfl
lemma
double_quot.coe_lift_sup_quot_quot_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_supₐ : ((A ⧸ I) ⧸ J.map (I^.quotient.mkₐ R)) ≃ₐ[R] A ⧸ I ⊔ J
@alg_equiv.of_ring_equiv R _ _ _ _ _ _ _ (quot_quot_equiv_quot_sup I J) (λ _, rfl)
def
double_quot.quot_quot_equiv_quot_supₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_equiv.of_ring_equiv" ]
`quot_quot_to_quot_add` and `lift_sup_quot_quot_mk` are inverse isomorphisms. In the case where `I ≤ J`, this is the Third Isomorphism Theorem (see `quot_quot_equiv_quot_of_le`).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_supₐ_to_ring_equiv : (quot_quot_equiv_quot_supₐ R I J).to_ring_equiv = quot_quot_equiv_quot_sup I J
rfl
lemma
double_quot.quot_quot_equiv_quot_supₐ_to_ring_equiv
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_quot_quot_equiv_quot_supₐ : ⇑(quot_quot_equiv_quot_supₐ R I J) = quot_quot_equiv_quot_sup I J
rfl
lemma
double_quot.coe_quot_quot_equiv_quot_supₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_supₐ_symm_to_ring_equiv: (quot_quot_equiv_quot_supₐ R I J).symm.to_ring_equiv = (quot_quot_equiv_quot_sup I J).symm
rfl
lemma
double_quot.quot_quot_equiv_quot_supₐ_symm_to_ring_equiv
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_quot_quot_equiv_quot_supₐ_symm: ⇑(quot_quot_equiv_quot_supₐ R I J).symm = (quot_quot_equiv_quot_sup I J).symm
rfl
lemma
double_quot.coe_quot_quot_equiv_quot_supₐ_symm
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_commₐ : ((A ⧸ I) ⧸ J.map (I^.quotient.mkₐ R)) ≃ₐ[R] ((A ⧸ J) ⧸ I.map (J^.quotient.mkₐ R))
@alg_equiv.of_ring_equiv R _ _ _ _ _ _ _ (quot_quot_equiv_comm I J) (λ _, rfl)
def
double_quot.quot_quot_equiv_commₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_equiv.of_ring_equiv" ]
The natural algebra isomorphism `(A / I) / J' → (A / J) / I'`, where `J'` (resp. `I'`) is the projection of `J` in `A / I` (resp. `I` in `A / J`).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_commₐ_to_ring_equiv : (quot_quot_equiv_commₐ R I J).to_ring_equiv = quot_quot_equiv_comm I J
rfl
lemma
double_quot.quot_quot_equiv_commₐ_to_ring_equiv
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_quot_quot_equiv_commₐ : ⇑(quot_quot_equiv_commₐ R I J) = quot_quot_equiv_comm I J
rfl
lemma
double_quot.coe_quot_quot_equiv_commₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_comm_symmₐ : (quot_quot_equiv_commₐ R I J).symm = quot_quot_equiv_commₐ R J I
-- TODO: should be `rfl` but times out alg_equiv.ext $ λ x, (fun_like.congr_fun (quot_quot_equiv_comm_symm I J) x : _)
lemma
double_quot.quot_quot_equiv_comm_symmₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_equiv.ext", "fun_like.congr_fun" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_comm_comp_quot_quot_mkₐ : alg_hom.comp ↑(quot_quot_equiv_commₐ R I J) (quot_quot_mkₐ R I J) = quot_quot_mkₐ R J I
alg_hom.ext $ quot_quot_equiv_comm_quot_quot_mk I J
lemma
double_quot.quot_quot_equiv_comm_comp_quot_quot_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_hom.comp", "alg_hom.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_leₐ (h : I ≤ J) : ((A ⧸ I) ⧸ (J.map (I^.quotient.mkₐ R))) ≃ₐ[R] A ⧸ J
@alg_equiv.of_ring_equiv R _ _ _ _ _ _ _ (quot_quot_equiv_quot_of_le h) (λ _, rfl)
def
double_quot.quot_quot_equiv_quot_of_leₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_equiv.of_ring_equiv" ]
The **third isomoprhism theorem** for rings. See `quot_quot_equiv_quot_sup` for version that does not assume an inclusion of ideals.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_leₐ_to_ring_equiv (h : I ≤ J) : (quot_quot_equiv_quot_of_leₐ R h).to_ring_equiv = quot_quot_equiv_quot_of_le h
rfl
lemma
double_quot.quot_quot_equiv_quot_of_leₐ_to_ring_equiv
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_quot_quot_equiv_quot_of_leₐ (h : I ≤ J) : ⇑(quot_quot_equiv_quot_of_leₐ R h) = quot_quot_equiv_quot_of_le h
rfl
lemma
double_quot.coe_quot_quot_equiv_quot_of_leₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_leₐ_symm_to_ring_equiv (h : I ≤ J) : (quot_quot_equiv_quot_of_leₐ R h).symm.to_ring_equiv = (quot_quot_equiv_quot_of_le h).symm
rfl
lemma
double_quot.quot_quot_equiv_quot_of_leₐ_symm_to_ring_equiv
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_quot_quot_equiv_quot_of_leₐ_symm (h : I ≤ J) : ⇑(quot_quot_equiv_quot_of_leₐ R h).symm = (quot_quot_equiv_quot_of_le h).symm
rfl
lemma
double_quot.coe_quot_quot_equiv_quot_of_leₐ_symm
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_le_comp_quot_quot_mkₐ (h : I ≤ J) : alg_hom.comp ↑(quot_quot_equiv_quot_of_leₐ R h) (quot_quot_mkₐ R I J) = J^.quotient.mkₐ R
rfl
lemma
double_quot.quot_quot_equiv_quot_of_le_comp_quot_quot_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_hom.comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_quot_equiv_quot_of_le_symm_comp_mkₐ (h : I ≤ J) : alg_hom.comp ↑(quot_quot_equiv_quot_of_leₐ R h).symm (J^.quotient.mkₐ R) = quot_quot_mkₐ R I J
rfl
lemma
double_quot.quot_quot_equiv_quot_of_le_symm_comp_mkₐ
ring_theory.ideal
src/ring_theory/ideal/quotient_operations.lean
[ "ring_theory.ideal.operations", "ring_theory.ideal.quotient" ]
[ "alg_hom.comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcd_eq_nat_gcd (m n : ℕ) : gcd m n = nat.gcd m n
rfl
lemma
gcd_eq_nat_gcd
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lcm_eq_nat_lcm (m n : ℕ) : lcm m n = nat.lcm m n
rfl
lemma
lcm_eq_nat_lcm
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normalize_of_nonneg {z : ℤ} (h : 0 ≤ z) : normalize z = z
show z * ↑(ite _ _ _) = z, by rw [if_pos h, units.coe_one, mul_one]
lemma
int.normalize_of_nonneg
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "mul_one", "normalize", "units.coe_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normalize_of_nonpos {z : ℤ} (h : z ≤ 0) : normalize z = -z
begin obtain rfl | h := h.eq_or_lt, { simp }, { change z * ↑(ite _ _ _) = -z, rw [if_neg (not_le_of_gt h), units.coe_neg, units.coe_one, mul_neg_one] } end
lemma
int.normalize_of_nonpos
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "mul_neg_one", "normalize", "units.coe_neg", "units.coe_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normalize_coe_nat (n : ℕ) : normalize (n : ℤ) = n
normalize_of_nonneg (coe_nat_le_coe_nat_of_le $ nat.zero_le n)
lemma
int.normalize_coe_nat
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "normalize" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
abs_eq_normalize (z : ℤ) : |z| = normalize z
by cases le_total 0 z; simp [normalize_of_nonneg, normalize_of_nonpos, *]
lemma
int.abs_eq_normalize
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "normalize" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonneg_of_normalize_eq_self {z : ℤ} (hz : normalize z = z) : 0 ≤ z
abs_eq_self.1 $ by rw [abs_eq_normalize, hz]
lemma
int.nonneg_of_normalize_eq_self
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "normalize" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonneg_iff_normalize_eq_self (z : ℤ) : normalize z = z ↔ 0 ≤ z
⟨nonneg_of_normalize_eq_self, normalize_of_nonneg⟩
lemma
int.nonneg_iff_normalize_eq_self
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "normalize" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_of_associated_of_nonneg {a b : ℤ} (h : associated a b) (ha : 0 ≤ a) (hb : 0 ≤ b) : a = b
dvd_antisymm_of_normalize_eq (normalize_of_nonneg ha) (normalize_of_nonneg hb) h.dvd h.symm.dvd
lemma
int.eq_of_associated_of_nonneg
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "associated", "dvd_antisymm_of_normalize_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_gcd (i j : ℤ) : ↑(int.gcd i j) = gcd_monoid.gcd i j
rfl
lemma
int.coe_gcd
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_lcm (i j : ℤ) : ↑(int.lcm i j) = gcd_monoid.lcm i j
rfl
lemma
int.coe_lcm
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "int.lcm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_abs_gcd (i j : ℤ) : nat_abs (gcd_monoid.gcd i j) = int.gcd i j
rfl
lemma
int.nat_abs_gcd
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_abs_lcm (i j : ℤ) : nat_abs (gcd_monoid.lcm i j) = int.lcm i j
rfl
lemma
int.nat_abs_lcm
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "int.lcm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_unit_of_abs (a : ℤ) : ∃ (u : ℤ) (h : is_unit u), (int.nat_abs a : ℤ) = u * a
begin cases (nat_abs_eq a) with h, { use [1, is_unit_one], rw [← h, one_mul], }, { use [-1, is_unit_one.neg], rw [← neg_eq_iff_eq_neg.mpr h], simp only [neg_mul, one_mul] } end
lemma
int.exists_unit_of_abs
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "is_unit", "is_unit_one", "neg_mul", "one_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcd_eq_nat_abs {a b : ℤ} : int.gcd a b = nat.gcd a.nat_abs b.nat_abs
rfl
lemma
int.gcd_eq_nat_abs
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcd_eq_one_iff_coprime {a b : ℤ} : int.gcd a b = 1 ↔ is_coprime a b
begin split, { intro hg, obtain ⟨ua, hua, ha⟩ := exists_unit_of_abs a, obtain ⟨ub, hub, hb⟩ := exists_unit_of_abs b, use [(nat.gcd_a (int.nat_abs a) (int.nat_abs b)) * ua, (nat.gcd_b (int.nat_abs a) (int.nat_abs b)) * ub], rw [mul_assoc, ← ha, mul_assoc, ← hb, mul_comm, mul_comm _ (int.nat_a...
lemma
int.gcd_eq_one_iff_coprime
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "by_contradiction", "dvd_add", "is_coprime", "mul_assoc", "mul_comm", "nat.gcd_a", "nat.gcd_b", "nat.gcd_eq_gcd_ab", "nat.prime.not_dvd_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coprime_iff_nat_coprime {a b : ℤ} : is_coprime a b ↔ nat.coprime a.nat_abs b.nat_abs
by rw [←gcd_eq_one_iff_coprime, nat.coprime_iff_gcd_eq_one, gcd_eq_nat_abs]
lemma
int.coprime_iff_nat_coprime
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "is_coprime", "nat.coprime_iff_gcd_eq_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcd_ne_one_iff_gcd_mul_right_ne_one {a : ℤ} {m n : ℕ} : a.gcd (m * n) ≠ 1 ↔ a.gcd m ≠ 1 ∨ a.gcd n ≠ 1
by simp only [gcd_eq_one_iff_coprime, ← not_and_distrib, not_iff_not, is_coprime.mul_right_iff]
lemma
int.gcd_ne_one_iff_gcd_mul_right_ne_one
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "is_coprime.mul_right_iff", "not_and_distrib", "not_iff_not" ]
If `gcd a (m * n) ≠ 1`, then `gcd a m ≠ 1` or `gcd a n ≠ 1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcd_eq_one_of_gcd_mul_right_eq_one_left {a : ℤ} {m n : ℕ} (h : a.gcd (m * n) = 1) : a.gcd m = 1
nat.dvd_one.mp $ trans_rel_left _ (gcd_dvd_gcd_mul_right_right a m n) h
lemma
int.gcd_eq_one_of_gcd_mul_right_eq_one_left
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "gcd_dvd_gcd_mul_right_right" ]
If `gcd a (m * n) = 1`, then `gcd a m = 1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcd_eq_one_of_gcd_mul_right_eq_one_right {a : ℤ} {m n : ℕ} (h : a.gcd (m * n) = 1) : a.gcd n = 1
nat.dvd_one.mp $ trans_rel_left _ (gcd_dvd_gcd_mul_left_right a n m) h
lemma
int.gcd_eq_one_of_gcd_mul_right_eq_one_right
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "gcd_dvd_gcd_mul_left_right" ]
If `gcd a (m * n) = 1`, then `gcd a n = 1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sq_of_gcd_eq_one {a b c : ℤ} (h : int.gcd a b = 1) (heq : a * b = c ^ 2) : ∃ (a0 : ℤ), a = a0 ^ 2 ∨ a = - (a0 ^ 2)
begin have h' : is_unit (gcd_monoid.gcd a b), { rw [← coe_gcd, h, int.coe_nat_one], exact is_unit_one }, obtain ⟨d, ⟨u, hu⟩⟩ := exists_associated_pow_of_mul_eq_pow h' heq, use d, rw ← hu, cases int.units_eq_one_or u with hu' hu'; { rw hu', simp } end
lemma
int.sq_of_gcd_eq_one
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "exists_associated_pow_of_mul_eq_pow", "int.units_eq_one_or", "is_unit", "is_unit_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sq_of_coprime {a b c : ℤ} (h : is_coprime a b) (heq : a * b = c ^ 2) : ∃ (a0 : ℤ), a = a0 ^ 2 ∨ a = - (a0 ^ 2)
sq_of_gcd_eq_one (gcd_eq_one_iff_coprime.mpr h) heq
lemma
int.sq_of_coprime
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "is_coprime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_abs_euclidean_domain_gcd (a b : ℤ) : int.nat_abs (euclidean_domain.gcd a b) = int.gcd a b
begin apply nat.dvd_antisymm; rw ← int.coe_nat_dvd, { rw int.nat_abs_dvd, exact int.dvd_gcd (euclidean_domain.gcd_dvd_left _ _) (euclidean_domain.gcd_dvd_right _ _) }, { rw int.dvd_nat_abs, exact euclidean_domain.dvd_gcd (int.gcd_dvd_left _ _) (int.gcd_dvd_right _ _) } end
lemma
int.nat_abs_euclidean_domain_gcd
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "euclidean_domain.dvd_gcd", "euclidean_domain.gcd", "euclidean_domain.gcd_dvd_left", "euclidean_domain.gcd_dvd_right", "int.coe_nat_dvd", "int.dvd_gcd", "int.dvd_nat_abs", "int.gcd_dvd_left", "int.gcd_dvd_right", "int.nat_abs_dvd" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
associates_int_equiv_nat : associates ℤ ≃ ℕ
begin refine ⟨λz, z.out.nat_abs, λn, associates.mk n, _, _⟩, { refine (assume a, quotient.induction_on' a $ assume a, associates.mk_eq_mk_iff_associated.2 $ associated.symm $ ⟨norm_unit a, _⟩), show normalize a = int.nat_abs (normalize a), rw [int.coe_nat_abs, int.abs_eq_normalize, normalize_idem] }, ...
def
associates_int_equiv_nat
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "associated.symm", "associates", "associates.mk", "int.abs_eq_normalize", "int.coe_nat_abs", "int.nat_abs_abs", "normalize", "normalize_idem", "quotient.induction_on'" ]
Maps an associate class of integers consisting of `-n, n` to `n : ℕ`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int.prime.dvd_mul {m n : ℤ} {p : ℕ} (hp : nat.prime p) (h : (p : ℤ) ∣ m * n) : p ∣ m.nat_abs ∨ p ∣ n.nat_abs
begin apply (nat.prime.dvd_mul hp).mp, rw ← int.nat_abs_mul, exact int.coe_nat_dvd_left.mp h end
lemma
int.prime.dvd_mul
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "int.nat_abs_mul", "nat.prime", "nat.prime.dvd_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int.prime.dvd_mul' {m n : ℤ} {p : ℕ} (hp : nat.prime p) (h : (p : ℤ) ∣ m * n) : (p : ℤ) ∣ m ∨ (p : ℤ) ∣ n
begin rw [int.coe_nat_dvd_left, int.coe_nat_dvd_left], exact int.prime.dvd_mul hp h end
lemma
int.prime.dvd_mul'
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "int.coe_nat_dvd_left", "int.prime.dvd_mul", "nat.prime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int.prime.dvd_pow {n : ℤ} {k p : ℕ} (hp : nat.prime p) (h : (p : ℤ) ∣ n ^ k) : p ∣ n.nat_abs
begin apply @nat.prime.dvd_of_dvd_pow _ _ k hp, rw ← int.nat_abs_pow, exact int.coe_nat_dvd_left.mp h end
lemma
int.prime.dvd_pow
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "int.nat_abs_pow", "nat.prime", "nat.prime.dvd_of_dvd_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int.prime.dvd_pow' {n : ℤ} {k p : ℕ} (hp : nat.prime p) (h : (p : ℤ) ∣ n ^ k) : (p : ℤ) ∣ n
begin rw int.coe_nat_dvd_left, exact int.prime.dvd_pow hp h end
lemma
int.prime.dvd_pow'
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "int.coe_nat_dvd_left", "int.prime.dvd_pow", "nat.prime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prime_two_or_dvd_of_dvd_two_mul_pow_self_two {m : ℤ} {p : ℕ} (hp : nat.prime p) (h : (p : ℤ) ∣ 2 * m ^ 2) : p = 2 ∨ p ∣ int.nat_abs m
begin cases int.prime.dvd_mul hp h with hp2 hpp, { apply or.intro_left, exact le_antisymm (nat.le_of_dvd zero_lt_two hp2) (nat.prime.two_le hp) }, { apply or.intro_right, rw [sq, int.nat_abs_mul] at hpp, exact (or_self _).mp ((nat.prime.dvd_mul hp).mp hpp)} end
lemma
prime_two_or_dvd_of_dvd_two_mul_pow_self_two
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "int.nat_abs_mul", "int.prime.dvd_mul", "nat.prime", "nat.prime.dvd_mul", "nat.prime.two_le", "zero_lt_two" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int.exists_prime_and_dvd {n : ℤ} (hn : n.nat_abs ≠ 1) : ∃ p, prime p ∧ p ∣ n
begin obtain ⟨p, pp, pd⟩ := nat.exists_prime_and_dvd hn, exact ⟨p, nat.prime_iff_prime_int.mp pp, int.coe_nat_dvd_left.mpr pd⟩, end
lemma
int.exists_prime_and_dvd
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "nat.exists_prime_and_dvd", "prime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat.factors_eq {n : ℕ} : normalized_factors n = n.factors
begin cases n, { simp }, rw [← multiset.rel_eq, ← associated_eq_eq], apply factors_unique (irreducible_of_normalized_factor) _, { rw [multiset.coe_prod, nat.prod_factors n.succ_ne_zero], apply normalized_factors_prod (nat.succ_ne_zero _) }, { apply_instance }, { intros x hx, rw [nat.irreducible_iff_...
theorem
nat.factors_eq
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "associated_eq_eq", "multiset.coe_prod", "multiset.rel_eq", "nat.irreducible_iff_prime", "nat.prime_iff", "nat.prime_of_mem_factors", "nat.prod_factors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat.factors_multiset_prod_of_irreducible {s : multiset ℕ} (h : ∀ (x : ℕ), x ∈ s → irreducible x) : normalized_factors (s.prod) = s
begin rw [← multiset.rel_eq, ← associated_eq_eq], apply unique_factorization_monoid.factors_unique irreducible_of_normalized_factor h (normalized_factors_prod _), rw [ne.def, multiset.prod_eq_zero_iff], intro con, exact not_irreducible_zero (h 0 con), end
lemma
nat.factors_multiset_prod_of_irreducible
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "associated_eq_eq", "con", "irreducible", "multiset", "multiset.prod_eq_zero_iff", "multiset.rel_eq", "not_irreducible_zero", "unique_factorization_monoid.factors_unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finite_int_iff_nat_abs_finite {a b : ℤ} : finite a b ↔ finite a.nat_abs b.nat_abs
by simp only [finite_def, ← int.nat_abs_dvd_iff_dvd, int.nat_abs_pow]
lemma
multiplicity.finite_int_iff_nat_abs_finite
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "finite", "int.nat_abs_dvd_iff_dvd", "int.nat_abs_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finite_int_iff {a b : ℤ} : finite a b ↔ (a.nat_abs ≠ 1 ∧ b ≠ 0)
by rw [finite_int_iff_nat_abs_finite, finite_nat_iff, pos_iff_ne_zero, int.nat_abs_ne_zero]
lemma
multiplicity.finite_int_iff
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "finite", "int.nat_abs_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decidable_nat : decidable_rel (λ a b : ℕ, (multiplicity a b).dom)
λ a b, decidable_of_iff _ finite_nat_iff.symm
instance
multiplicity.decidable_nat
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "decidable_of_iff", "multiplicity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decidable_int : decidable_rel (λ a b : ℤ, (multiplicity a b).dom)
λ a b, decidable_of_iff _ finite_int_iff.symm
instance
multiplicity.decidable_int
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "decidable_of_iff", "multiplicity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
induction_on_primes {P : ℕ → Prop} (h₀ : P 0) (h₁ : P 1) (h : ∀ p a : ℕ, p.prime → P a → P (p * a)) (n : ℕ) : P n
begin apply unique_factorization_monoid.induction_on_prime, exact h₀, { intros n h, rw nat.is_unit_iff.1 h, exact h₁, }, { intros a p _ hp ha, exact h p a hp.nat_prime ha, }, end
lemma
induction_on_primes
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "unique_factorization_monoid.induction_on_prime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int.associated_nat_abs (k : ℤ) : associated k k.nat_abs
associated_of_dvd_dvd (int.coe_nat_dvd_right.mpr dvd_rfl) (int.nat_abs_dvd.mpr dvd_rfl)
lemma
int.associated_nat_abs
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "associated", "associated_of_dvd_dvd", "dvd_rfl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int.prime_iff_nat_abs_prime {k : ℤ} : prime k ↔ nat.prime k.nat_abs
(int.associated_nat_abs k).prime_iff.trans nat.prime_iff_prime_int.symm
lemma
int.prime_iff_nat_abs_prime
ring_theory.int
src/ring_theory/int/basic.lean
[ "algebra.euclidean_domain.basic", "data.nat.factors", "ring_theory.coprime.basic", "ring_theory.principal_ideal_domain" ]
[ "int.associated_nat_abs", "nat.prime", "prime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83