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lift_eq_iff {x y : R × M} : lift hg (mk' S x.1 x.2) = lift hg (mk' S y.1 y.2) ↔ g (x.1 * y.2) = g (y.1 * x.2)
(to_localization_map M S).lift_eq_iff _
lemma
is_localization.lift_eq_iff
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "lift", "mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_comp : (lift hg).comp (algebra_map R S) = g
ring_hom.ext $ monoid_hom.ext_iff.1 $ (to_localization_map M S).lift_comp _
lemma
is_localization.lift_comp
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "lift", "lift_comp", "ring_hom.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_of_comp (j : S →+* P) : lift (is_unit_comp M j) = j
ring_hom.ext $ monoid_hom.ext_iff.1 $ (to_localization_map M S).lift_of_comp j.to_monoid_hom
lemma
is_localization.lift_of_comp
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "lift", "ring_hom.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom_ext ⦃j k : S →* P⦄ (h : j.comp (algebra_map R S : R →* S) = k.comp (algebra_map R S)) : j = k
submonoid.localization_map.epic_of_localization_map (to_localization_map M S) $ monoid_hom.congr_fun h
lemma
is_localization.monoid_hom_ext
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "monoid_hom.congr_fun", "submonoid.localization_map.epic_of_localization_map" ]
See note [partially-applied ext lemmas]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom_ext ⦃j k : S →+* P⦄ (h : j.comp (algebra_map R S) = k.comp (algebra_map R S)) : j = k
ring_hom.coe_monoid_hom_injective $ monoid_hom_ext M $ monoid_hom.ext $ ring_hom.congr_fun h
lemma
is_localization.ring_hom_ext
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "monoid_hom.ext", "ring_hom.coe_monoid_hom_injective", "ring_hom.congr_fun", "ring_hom_ext" ]
See note [partially-applied ext lemmas]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_hom_subsingleton [algebra R P] : subsingleton (S →ₐ[R] P)
⟨λ f g, alg_hom.coe_ring_hom_injective $ is_localization.ring_hom_ext M $ by rw [f.comp_algebra_map, g.comp_algebra_map]⟩
lemma
is_localization.alg_hom_subsingleton
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_hom.coe_ring_hom_injective", "algebra", "is_localization.ring_hom_ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext (j k : S → P) (hj1 : j 1 = 1) (hk1 : k 1 = 1) (hjm : ∀ a b, j (a * b) = j a * j b) (hkm : ∀ a b, k (a * b) = k a * k b) (h : ∀ a, j (algebra_map R S a) = k (algebra_map R S a)) : j = k
monoid_hom.mk.inj (monoid_hom_ext M $ monoid_hom.ext h : (⟨j, hj1, hjm⟩ : S →* P) = ⟨k, hk1, hkm⟩)
lemma
is_localization.ext
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "monoid_hom.ext" ]
To show `j` and `k` agree on the whole localization, it suffices to show they agree on the image of the base ring, if they preserve `1` and `*`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_unique {j : S →+* P} (hj : ∀ x, j ((algebra_map R S) x) = g x) : lift hg = j
ring_hom.ext $ monoid_hom.ext_iff.1 $ @submonoid.localization_map.lift_unique _ _ _ _ _ _ _ (to_localization_map M S) g.to_monoid_hom hg j.to_monoid_hom hj
lemma
is_localization.lift_unique
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "lift", "lift_unique", "ring_hom.ext", "submonoid.localization_map.lift_unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_id (x) : lift (map_units S : ∀ y : M, is_unit _) x = x
(to_localization_map M S).lift_id _
lemma
is_localization.lift_id
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "is_unit", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_surjective_iff : surjective (lift hg : S → P) ↔ ∀ v : P, ∃ x : R × M, v * g x.2 = g x.1
(to_localization_map M S).lift_surjective_iff hg
lemma
is_localization.lift_surjective_iff
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_injective_iff : injective (lift hg : S → P) ↔ ∀ x y, algebra_map R S x = algebra_map R S y ↔ g x = g y
(to_localization_map M S).lift_injective_iff hg
lemma
is_localization.lift_injective_iff
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map (g : R →+* P) (hy : M ≤ T.comap g) : S →+* Q
@lift R _ M _ _ _ _ _ _ ((algebra_map P Q).comp g) (λ y, map_units _ ⟨g y, hy y.2⟩)
def
is_localization.map
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "lift" ]
Map a homomorphism `g : R →+* P` to `S →+* Q`, where `S` and `Q` are localizations of `R` and `P` at `M` and `T` respectively, such that `g(M) ⊆ T`. We send `z : S` to `algebra_map P Q (g x) * (algebra_map P Q (g y))⁻¹`, where `(x, y) : R × M` are such that `z = f x * (f y)⁻¹`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_eq (x) : map Q g hy ((algebra_map R S) x) = algebra_map P Q (g x)
lift_eq (λ y, map_units _ ⟨g y, hy y.2⟩) x
lemma
is_localization.map_eq
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "map_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_comp : (map Q g hy).comp (algebra_map R S) = (algebra_map P Q).comp g
lift_comp $ λ y, map_units _ ⟨g y, hy y.2⟩
lemma
is_localization.map_comp
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "lift_comp", "map_comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mk' (x) (y : M) : map Q g hy (mk' S x y) = mk' Q (g x) ⟨g y, hy y.2⟩
@submonoid.localization_map.map_mk' _ _ _ _ _ _ _ (to_localization_map M S) g.to_monoid_hom _ (λ y, hy y.2) _ _ (to_localization_map T Q) _ _
lemma
is_localization.map_mk'
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "mk'", "submonoid.localization_map.map_mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_id (z : S) (h : M ≤ M.comap (ring_hom.id R) := le_refl M) : map S (ring_hom.id _) h z = z
lift_id _
lemma
is_localization.map_id
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "map_id", "ring_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_unique (j : S →+* Q) (hj : ∀ x : R, j (algebra_map R S x) = algebra_map P Q (g x)) : map Q g hy = j
lift_unique (λ y, map_units _ ⟨g y, hy y.2⟩) hj
lemma
is_localization.map_unique
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "lift_unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_comp_map {A : Type*} [comm_semiring A] {U : submonoid A} {W} [comm_semiring W] [algebra A W] [is_localization U W] {l : P →+* A} (hl : T ≤ U.comap l) : (map W l hl).comp (map Q g hy : S →+* _) = map W (l.comp g) (λ x hx, hl (hy hx))
ring_hom.ext $ λ x, @submonoid.localization_map.map_map _ _ _ _ _ P _ (to_localization_map M S) g _ _ _ _ _ _ _ _ _ _ (to_localization_map U W) l _ x
lemma
is_localization.map_comp_map
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "comm_semiring", "is_localization", "ring_hom.ext", "submonoid", "submonoid.localization_map.map_map" ]
If `comm_semiring` homs `g : R →+* P, l : P →+* A` induce maps of localizations, the composition of the induced maps equals the map of localizations induced by `l ∘ g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_map {A : Type*} [comm_semiring A] {U : submonoid A} {W} [comm_semiring W] [algebra A W] [is_localization U W] {l : P →+* A} (hl : T ≤ U.comap l) (x : S) : map W l hl (map Q g hy x) = map W (l.comp g) (λ x hx, hl (hy hx)) x
by rw ←map_comp_map hy hl; refl
lemma
is_localization.map_map
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "comm_semiring", "is_localization", "submonoid" ]
If `comm_semiring` homs `g : R →+* P, l : P →+* A` induce maps of localizations, the composition of the induced maps equals the map of localizations induced by `l ∘ g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_smul (x : S) (z : R) : map Q g hy (z • x : S) = g z • map Q g hy x
by rw [algebra.smul_def, algebra.smul_def, ring_hom.map_mul, map_eq]
lemma
is_localization.map_smul
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra.smul_def", "map_eq", "ring_hom.map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_equiv_of_ring_equiv (h : R ≃+* P) (H : M.map h.to_monoid_hom = T) : S ≃+* Q
have H' : T.map h.symm.to_monoid_hom = M, by { rw [← M.map_id, ← H, submonoid.map_map], congr, ext, apply h.symm_apply_apply }, { to_fun := map Q (h : R →+* P) (M.le_comap_of_map_le (le_of_eq H)), inv_fun := map S (h.symm : P →+* R) (T.le_comap_of_map_le (le_of_eq H')), left_inv := λ x, by { rw [map_map, map_unique...
def
is_localization.ring_equiv_of_ring_equiv
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "inv_fun", "ring_hom.id", "ring_hom.id_apply", "submonoid.map_map" ]
If `S`, `Q` are localizations of `R` and `P` at submonoids `M, T` respectively, an isomorphism `j : R ≃+* P` such that `j(M) = T` induces an isomorphism of localizations `S ≃+* Q`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_equiv_of_ring_equiv_eq_map {j : R ≃+* P} (H : M.map j.to_monoid_hom = T) : (ring_equiv_of_ring_equiv S Q j H : S →+* Q) = map Q (j : R →+* P) (M.le_comap_of_map_le (le_of_eq H))
rfl
lemma
is_localization.ring_equiv_of_ring_equiv_eq_map
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_equiv_of_ring_equiv_eq {j : R ≃+* P} (H : M.map j.to_monoid_hom = T) (x) : ring_equiv_of_ring_equiv S Q j H ((algebra_map R S) x) = algebra_map P Q (j x)
map_eq _ _
lemma
is_localization.ring_equiv_of_ring_equiv_eq
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "map_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_equiv_of_ring_equiv_mk' {j : R ≃+* P} (H : M.map j.to_monoid_hom = T) (x : R) (y : M) : ring_equiv_of_ring_equiv S Q j H (mk' S x y) = mk' Q (j x) ⟨j y, show j y ∈ T, from H ▸ set.mem_image_of_mem j y.2⟩
map_mk' _ _ _
lemma
is_localization.ring_equiv_of_ring_equiv_mk'
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "mk'", "set.mem_image_of_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_equiv : S ≃ₐ[R] Q
{ commutes' := ring_equiv_of_ring_equiv_eq _, .. ring_equiv_of_ring_equiv S Q (ring_equiv.refl R) M.map_id }
def
is_localization.alg_equiv
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "ring_equiv.refl" ]
If `S`, `Q` are localizations of `R` at the submonoid `M` respectively, there is an isomorphism of localizations `S ≃ₐ[R] Q`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_equiv_mk' (x : R) (y : M) : alg_equiv M S Q (mk' S x y) = mk' Q x y
map_mk' _ _ _
lemma
is_localization.alg_equiv_mk'
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_equiv_symm_mk' (x : R) (y : M) : (alg_equiv M S Q).symm (mk' Q x y) = mk' S x y
map_mk' _ _ _
lemma
is_localization.alg_equiv_symm_mk'
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization_of_alg_equiv [algebra R P] [is_localization M S] (h : S ≃ₐ[R] P) : is_localization M P
begin constructor, { intro y, convert (is_localization.map_units S y).map h.to_alg_hom.to_ring_hom.to_monoid_hom, exact (h.commutes y).symm }, { intro y, obtain ⟨⟨x, s⟩, e⟩ := is_localization.surj M (h.symm y), apply_fun h at e, simp only [h.map_mul, h.apply_symm_apply, h.commutes] at e, e...
lemma
is_localization.is_localization_of_alg_equiv
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "is_localization" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization_iff_of_alg_equiv [algebra R P] (h : S ≃ₐ[R] P) : is_localization M S ↔ is_localization M P
⟨λ _, by exactI is_localization_of_alg_equiv M h, λ _, by exactI is_localization_of_alg_equiv M h.symm⟩
lemma
is_localization.is_localization_iff_of_alg_equiv
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "is_localization" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization_iff_of_ring_equiv (h : S ≃+* P) : is_localization M S ↔ @@is_localization _ M P _ (h.to_ring_hom.comp $ algebra_map R S).to_algebra
begin letI := (h.to_ring_hom.comp $ algebra_map R S).to_algebra, exact is_localization_iff_of_alg_equiv M { commutes' := λ _, rfl, ..h }, end
lemma
is_localization.is_localization_iff_of_ring_equiv
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "is_localization" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization_of_base_ring_equiv [is_localization M S] (h : R ≃+* P) : @@is_localization _ (M.map h.to_monoid_hom) S _ ((algebra_map R S).comp h.symm.to_ring_hom).to_algebra
begin constructor, { rintros ⟨_, ⟨y, hy, rfl⟩⟩, convert is_localization.map_units S ⟨y, hy⟩, dsimp only [ring_hom.algebra_map_to_algebra, ring_hom.comp_apply], exact congr_arg _ (h.symm_apply_apply _) }, { intro y, obtain ⟨⟨x, s⟩, e⟩ := is_localization.surj M y, refine ⟨⟨h x, _, _, s.prop, rfl...
lemma
is_localization.is_localization_of_base_ring_equiv
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "is_localization", "ring_equiv.apply_symm_apply", "ring_equiv.map_mul", "ring_hom.algebra_map_to_algebra", "ring_hom.comp_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization_iff_of_base_ring_equiv (h : R ≃+* P) : is_localization M S ↔ @@is_localization _ (M.map h.to_monoid_hom) S _ ((algebra_map R S).comp h.symm.to_ring_hom).to_algebra
begin refine ⟨λ _, by exactI is_localization_of_base_ring_equiv _ _ h, _⟩, letI := ((algebra_map R S).comp h.symm.to_ring_hom).to_algebra, intro H, convert @@is_localization_of_base_ring_equiv _ _ _ _ _ _ H h.symm, { erw [submonoid.map_equiv_eq_comap_symm, submonoid.comap_map_eq_of_injective], exact h.to_...
lemma
is_localization.is_localization_iff_of_base_ring_equiv
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra.algebra_ext", "algebra_map", "is_localization", "ring_equiv.symm_symm", "ring_equiv.symm_to_ring_hom_comp_to_ring_hom", "ring_hom.algebra_map_to_algebra", "ring_hom.comp_assoc", "ring_hom.comp_id", "submonoid.comap_map_eq_of_injective", "submonoid.map_equiv_eq_comap_symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
non_zero_divisors_le_comap [is_localization M S] : non_zero_divisors R ≤ (non_zero_divisors S).comap (algebra_map R S)
begin rintros a ha b (e : b * algebra_map R S a = 0), obtain ⟨x, s, rfl⟩ := mk'_surjective M b, rw [← @mk'_one R _ M, ← mk'_mul, ← (algebra_map R S).map_zero, ← @mk'_one R _ M, is_localization.eq] at e, obtain ⟨c, e⟩ := e, rw [mul_zero, mul_zero, submonoid.coe_one, one_mul, ←mul_assoc] at e, rw mk'_eq_z...
lemma
is_localization.non_zero_divisors_le_comap
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "is_localization", "is_localization.eq", "mk'_one", "mk'_surjective", "mul_zero", "non_zero_divisors", "one_mul", "submonoid.coe_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_non_zero_divisors_le [is_localization M S] : (non_zero_divisors R).map (algebra_map R S) ≤ non_zero_divisors S
submonoid.map_le_iff_le_comap.mpr (non_zero_divisors_le_comap M S)
lemma
is_localization.map_non_zero_divisors_le
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "is_localization", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add (z w : localization M) : localization M
localization.lift_on₂ z w (λ a b c d, mk ((b : R) * c + d * a) (b * d)) $ λ a a' b b' c c' d d' h1 h2, mk_eq_mk_iff.2 begin rw r_eq_r' at h1 h2 ⊢, cases h1 with t₅ ht₅, cases h2 with t₆ ht₆, use t₅ * t₆, dsimp only, calc (↑t₅ * ↑t₆) * ((↑b' * ↑d') * ((b : R) * c + d * a)) = (t₆ * (d' * c)) * (t₅ * ...
def
localization.add
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization", "localization.lift_on₂", "ring" ]
Addition in a ring localization is defined as `⟨a, b⟩ + ⟨c, d⟩ = ⟨b * c + d * a, b * d⟩`. Should not be confused with `add_localization.add`, which is defined as `⟨a, b⟩ + ⟨c, d⟩ = ⟨a + c, b + d⟩`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_mk (a b c d) : (mk a b : localization M) + mk c d = mk (b * c + d * a) (b * d)
by { unfold has_add.add localization.add, apply lift_on₂_mk }
lemma
localization.add_mk
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization", "localization.add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_mk_self (a b c) : (mk a b : localization M) + mk c b = mk (a + c) b
begin rw [add_mk, mk_eq_mk_iff, r_eq_r'], refine (r' M).symm ⟨1, _⟩, simp only [submonoid.coe_one, submonoid.coe_mul], ring end
lemma
localization.add_mk_self
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization", "ring", "submonoid.coe_mul", "submonoid.coe_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tac
`[ { intros, simp only [add_mk, localization.mk_mul, ← localization.mk_zero 1], refine mk_eq_mk_iff.mpr (r_of_eq _), simp only [submonoid.coe_mul], ring }]
def
localization.tac
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization.mk_mul", "localization.mk_zero", "ring", "submonoid.coe_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_add_monoid_hom (b : M) : R →+ localization M
{ to_fun := λ a, mk a b, map_zero' := mk_zero _, map_add' := λ x y, (add_mk_self _ _ _).symm }
def
localization.mk_add_monoid_hom
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization" ]
For any given denominator `b : M`, the map `a ↦ a / b` is an `add_monoid_hom` from `R` to `localization M`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_sum {ι : Type*} (f : ι → R) (s : finset ι) (b : M) : mk (∑ i in s, f i) b = ∑ i in s, mk (f i) b
(mk_add_monoid_hom b).map_sum f s
lemma
localization.mk_sum
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_list_sum (l : list R) (b : M) : mk l.sum b = (l.map $ λ a, mk a b).sum
(mk_add_monoid_hom b).map_list_sum l
lemma
localization.mk_list_sum
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_multiset_sum (l : multiset R) (b : M) : mk l.sum b = (l.map $ λ a, mk a b).sum
(mk_add_monoid_hom b).map_multiset_sum l
lemma
localization.mk_multiset_sum
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "multiset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_localization_map_eq_monoid_of : to_localization_map M (localization M) = monoid_of M
rfl
lemma
localization.to_localization_map_eq_monoid_of
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_of_eq_algebra_map (x) : (monoid_of M).to_map x = algebra_map R (localization M) x
rfl
lemma
localization.monoid_of_eq_algebra_map
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "localization" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_one_eq_algebra_map (x) : mk x 1 = algebra_map R (localization M) x
rfl
lemma
localization.mk_one_eq_algebra_map
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "localization" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_eq_mk'_apply (x y) : mk x y = is_localization.mk' (localization M) x y
by rw [mk_eq_monoid_of_mk'_apply, mk', to_localization_map_eq_monoid_of]
lemma
localization.mk_eq_mk'_apply
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "is_localization.mk'", "localization", "mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_eq_mk' : (mk : R → M → localization M) = is_localization.mk' (localization M)
mk_eq_monoid_of_mk'
lemma
localization.mk_eq_mk'
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "is_localization.mk'", "localization", "mk_eq_mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_algebra_map {A : Type*} [comm_semiring A] [algebra A R] (m : A) : mk (algebra_map A R m) 1 = algebra_map A (localization M) m
by rw [mk_eq_mk', mk'_eq_iff_eq_mul, submonoid.coe_one, map_one, mul_one]; refl
lemma
localization.mk_algebra_map
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "algebra_map", "comm_semiring", "localization", "map_one", "mk_eq_mk'", "mul_one", "submonoid.coe_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_nat_cast (m : ℕ) : (mk m 1 : localization M) = m
by simpa using @mk_algebra_map R _ M ℕ _ _ m
lemma
localization.mk_nat_cast
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_equiv : localization M ≃ₐ[R] S
is_localization.alg_equiv M _ _
def
localization.alg_equiv
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "is_localization.alg_equiv", "localization" ]
The localization of `R` at `M` as a quotient type is isomorphic to any other localization.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.is_localization.unique (R Rₘ) [comm_semiring R] [comm_semiring Rₘ] (M : submonoid R) [subsingleton R] [algebra R Rₘ] [is_localization M Rₘ] : unique Rₘ
have inhabited Rₘ := ⟨1⟩, by exactI (alg_equiv M Rₘ).symm.injective.unique
def
is_localization.unique
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "algebra", "comm_semiring", "is_localization", "submonoid", "unique" ]
The localization of a singleton is a singleton. Cannot be an instance due to metavariables.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_equiv_mk' (x : R) (y : M) : alg_equiv M S (mk' (localization M) x y) = mk' S x y
alg_equiv_mk' _ _
lemma
localization.alg_equiv_mk'
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "localization", "mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_equiv_symm_mk' (x : R) (y : M) : (alg_equiv M S).symm (mk' S x y) = mk' (localization M) x y
alg_equiv_symm_mk' _ _
lemma
localization.alg_equiv_symm_mk'
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "localization", "mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_equiv_mk (x y) : alg_equiv M S (mk x y) = mk' S x y
by rw [mk_eq_mk', alg_equiv_mk']
lemma
localization.alg_equiv_mk
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "mk'", "mk_eq_mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_equiv_symm_mk (x : R) (y : M) : (alg_equiv M S).symm (mk' S x y) = mk x y
by rw [mk_eq_mk', alg_equiv_symm_mk']
lemma
localization.alg_equiv_symm_mk
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "alg_equiv", "mk'", "mk_eq_mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg (z : localization M) : localization M
localization.lift_on z (λ a b, mk (-a) b) $ λ a b c d h, mk_eq_mk_iff.2 begin rw r_eq_r' at h ⊢, cases h with t ht, use t, rw [mul_neg, mul_neg, ht], ring_nf, end
def
localization.neg
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization", "localization.lift_on", "mul_neg" ]
Negation in a ring localization is defined as `-⟨a, b⟩ = ⟨-a, b⟩`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_mk (a b) : -(mk a b : localization M) = mk (-a) b
by { unfold has_neg.neg localization.neg, apply lift_on_mk }
lemma
localization.neg_mk
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization", "localization.neg" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_mk (a c) (b d) : (mk a b : localization M) - mk c d = mk (d * a - b * c) (b * d)
calc mk a b - mk c d = mk a b + (- mk c d) : sub_eq_add_neg _ _ ... = mk a b + (mk (-c) d) : by rw neg_mk ... = mk (b * (-c) + d * a) (b * d) : add_mk _ _ _ _ ... = mk (d * a - b * c) (b * d) : by congr'; ring
lemma
localization.sub_mk
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_int_cast (m : ℤ) : (mk m 1 : localization M) = m
by simpa using @mk_algebra_map R _ M ℤ _ _ m
lemma
localization.mk_int_cast
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "localization" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_map_eq_zero_iff {x : R} (hM : M ≤ non_zero_divisors R) : algebra_map R S x = 0 ↔ x = 0
begin rw ← (algebra_map R S).map_zero, split; intro h, { cases (eq_iff_exists M S).mp h with c hc, rw [mul_zero, mul_comm] at hc, exact hM c.2 x hc }, { rw h }, end
lemma
is_localization.to_map_eq_zero_iff
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "mul_comm", "mul_zero", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective (hM : M ≤ non_zero_divisors R) : injective (algebra_map R S)
begin rw injective_iff_map_eq_zero (algebra_map R S), intros a ha, rwa to_map_eq_zero_iff S hM at ha end
lemma
is_localization.injective
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_map_ne_zero_of_mem_non_zero_divisors [nontrivial R] (hM : M ≤ non_zero_divisors R) {x : R} (hx : x ∈ non_zero_divisors R) : algebra_map R S x ≠ 0
show (algebra_map R S).to_monoid_with_zero_hom x ≠ 0, from map_ne_zero_of_mem_non_zero_divisors (algebra_map R S) (is_localization.injective S hM) hx
lemma
is_localization.to_map_ne_zero_of_mem_non_zero_divisors
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "is_localization.injective", "map_ne_zero_of_mem_non_zero_divisors", "non_zero_divisors", "nontrivial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sec_snd_ne_zero [nontrivial R] (hM : M ≤ non_zero_divisors R) (x : S) : ((sec M x).snd : R) ≠ 0
non_zero_divisors.coe_ne_zero ⟨(sec M x).snd.val, hM (sec M x).snd.property⟩
lemma
is_localization.sec_snd_ne_zero
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "non_zero_divisors", "non_zero_divisors.coe_ne_zero", "nontrivial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sec_fst_ne_zero [nontrivial R] [no_zero_divisors S] (hM : M ≤ non_zero_divisors R) {x : S} (hx : x ≠ 0) : (sec M x).fst ≠ 0
begin have hsec := sec_spec M x, intro hfst, rw [hfst, map_zero, mul_eq_zero, _root_.map_eq_zero_iff] at hsec, { exact or.elim hsec hx (sec_snd_ne_zero hM x) }, { exact is_localization.injective S hM } end
lemma
is_localization.sec_fst_ne_zero
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "is_localization.injective", "mul_eq_zero", "no_zero_divisors", "non_zero_divisors", "nontrivial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_injective_of_injective (hg : function.injective g) [is_localization (M.map g : submonoid P) Q] : function.injective (map Q g M.le_comap_map : S → Q)
begin rw injective_iff_map_eq_zero, intros z hz, obtain ⟨a, b, rfl⟩ := mk'_surjective M z, rw [map_mk', mk'_eq_zero_iff] at hz, obtain ⟨⟨m', hm'⟩, hm⟩ := hz, rw submonoid.mem_map at hm', obtain ⟨n, hn, hnm⟩ := hm', rw [subtype.coe_mk, ← hnm, ← map_mul, ← map_zero g] at hm, rw [mk'_eq_zero_iff], exa...
lemma
is_localization.map_injective_of_injective
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "is_localization", "map_mul", "mk'_surjective", "submonoid", "submonoid.mem_map", "subtype.coe_mk" ]
Injectivity of a map descends to the map induced on localizations.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
no_zero_divisors_of_le_non_zero_divisors [algebra A S] {M : submonoid A} [is_localization M S] (hM : M ≤ non_zero_divisors A) : no_zero_divisors S
{ eq_zero_or_eq_zero_of_mul_eq_zero := begin intros z w h, cases surj M z with x hx, cases surj M w with y hy, have : z * w * algebra_map A S y.2 * algebra_map A S x.2 = algebra_map A S x.1 * algebra_map A S y.1, by rw [mul_assoc z, hy, ←hx]; ring, rw [h, zero_mul, zero_m...
theorem
is_localization.no_zero_divisors_of_le_non_zero_divisors
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "algebra_map", "is_localization", "map_mul", "mul_assoc", "no_zero_divisors", "non_zero_divisors", "ring", "submonoid", "zero_mul" ]
A `comm_ring` `S` which is the localization of a ring `R` without zero divisors at a subset of non-zero elements does not have zero divisors. See note [reducible non-instances].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_domain_of_le_non_zero_divisors [algebra A S] {M : submonoid A} [is_localization M S] (hM : M ≤ non_zero_divisors A) : is_domain S
begin apply no_zero_divisors.to_is_domain _, { exact ⟨⟨(algebra_map A S) 0, (algebra_map A S) 1, λ h, zero_ne_one (is_localization.injective S hM h)⟩⟩ }, { exact no_zero_divisors_of_le_non_zero_divisors _ hM } end
theorem
is_localization.is_domain_of_le_non_zero_divisors
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "algebra_map", "is_domain", "is_localization", "is_localization.injective", "no_zero_divisors.to_is_domain", "non_zero_divisors", "submonoid", "zero_ne_one" ]
A `comm_ring` `S` which is the localization of an integral domain `R` at a subset of non-zero elements is an integral domain. See note [reducible non-instances].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_domain_localization {M : submonoid A} (hM : M ≤ non_zero_divisors A) : is_domain (localization M)
is_domain_of_le_non_zero_divisors _ hM
theorem
is_localization.is_domain_localization
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "is_domain", "localization", "non_zero_divisors", "submonoid" ]
The localization at of an integral domain to a set of non-zero elements is an integral domain. See note [reducible non-instances].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_field.localization_map_bijective {R Rₘ : Type*} [comm_ring R] [comm_ring Rₘ] {M : submonoid R} (hM : (0 : R) ∉ M) (hR : is_field R) [algebra R Rₘ] [is_localization M Rₘ] : function.bijective (algebra_map R Rₘ)
begin letI := hR.to_field, replace hM := le_non_zero_divisors_of_no_zero_divisors hM, refine ⟨is_localization.injective _ hM, λ x, _⟩, obtain ⟨r, ⟨m, hm⟩, rfl⟩ := mk'_surjective M x, obtain ⟨n, hn⟩ := hR.mul_inv_cancel (non_zero_divisors.ne_zero $ hM hm), exact ⟨r * n, by erw [eq_mk'_iff_mul_eq, ←map_mul, m...
lemma
is_field.localization_map_bijective
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "algebra_map", "comm_ring", "is_field", "is_localization", "le_non_zero_divisors_of_no_zero_divisors", "mk'_surjective", "mul_assoc", "mul_comm", "mul_one", "non_zero_divisors.ne_zero", "submonoid" ]
If `R` is a field, then localizing at a submonoid not containing `0` adds no new elements.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
field.localization_map_bijective {K Kₘ : Type*} [field K] [comm_ring Kₘ] {M : submonoid K} (hM : (0 : K) ∉ M) [algebra K Kₘ] [is_localization M Kₘ] : function.bijective (algebra_map K Kₘ)
(field.to_is_field K).localization_map_bijective hM
lemma
field.localization_map_bijective
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "algebra_map", "comm_ring", "field", "field.to_is_field", "is_localization", "submonoid" ]
If `R` is a field, then localizing at a submonoid not containing `0` adds no new elements.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
localization_algebra : algebra Rₘ Sₘ
(map Sₘ (algebra_map R S) (show _ ≤ (algebra.algebra_map_submonoid S M).comap _, from M.le_comap_map) : Rₘ →+* Sₘ).to_algebra
def
localization_algebra
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra", "algebra.algebra_map_submonoid", "algebra_map" ]
Definition of the natural algebra induced by the localization of an algebra. Given an algebra `R → S`, a submonoid `R` of `M`, and a localization `Rₘ` for `M`, let `Sₘ` be the localization of `S` to the image of `M` under `algebra_map R S`. Then this is the natural algebra structure on `Rₘ → Sₘ`, such that the entire s...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization.map_units_map_submonoid (y : M) : is_unit (algebra_map R Sₘ y)
begin rw is_scalar_tower.algebra_map_apply _ S, exact is_localization.map_units Sₘ ⟨algebra_map R S y, algebra.mem_algebra_map_submonoid_of_mem y⟩ end
lemma
is_localization.map_units_map_submonoid
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra.mem_algebra_map_submonoid_of_mem", "algebra_map", "is_scalar_tower.algebra_map_apply", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization.algebra_map_mk' (x : R) (y : M) : algebra_map Rₘ Sₘ (is_localization.mk' Rₘ x y) = is_localization.mk' Sₘ (algebra_map R S x) ⟨algebra_map R S y, algebra.mem_algebra_map_submonoid_of_mem y⟩
begin rw [is_localization.eq_mk'_iff_mul_eq, subtype.coe_mk, ← is_scalar_tower.algebra_map_apply, ← is_scalar_tower.algebra_map_apply, is_scalar_tower.algebra_map_apply R Rₘ Sₘ, is_scalar_tower.algebra_map_apply R Rₘ Sₘ, ← _root_.map_mul, mul_comm, is_localization.mul_mk'_eq_mk'_of_mul], exact con...
lemma
is_localization.algebra_map_mk'
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra.mem_algebra_map_submonoid_of_mem", "algebra_map", "is_localization.eq_mk'_iff_mul_eq", "is_localization.mk'", "is_localization.mk'_mul_cancel_left", "is_localization.mul_mk'_eq_mk'_of_mul", "is_scalar_tower.algebra_map_apply", "mul_comm", "subtype.coe_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization.algebra_map_eq_map_map_submonoid : algebra_map Rₘ Sₘ = map Sₘ (algebra_map R S) (show _ ≤ (algebra.algebra_map_submonoid S M).comap _, from M.le_comap_map)
eq.symm $ is_localization.map_unique _ (algebra_map Rₘ Sₘ) (λ x, by rw [← is_scalar_tower.algebra_map_apply R S Sₘ, ← is_scalar_tower.algebra_map_apply R Rₘ Sₘ])
lemma
is_localization.algebra_map_eq_map_map_submonoid
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra.algebra_map_submonoid", "algebra_map", "is_localization.map_unique", "is_scalar_tower.algebra_map_apply" ]
If the square below commutes, the bottom map is uniquely specified: ``` R → S ↓ ↓ Rₘ → Sₘ ```
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization.algebra_map_apply_eq_map_map_submonoid (x) : algebra_map Rₘ Sₘ x = map Sₘ (algebra_map R S) (show _ ≤ (algebra.algebra_map_submonoid S M).comap _, from M.le_comap_map) x
fun_like.congr_fun (is_localization.algebra_map_eq_map_map_submonoid _ _ _ _) x
lemma
is_localization.algebra_map_apply_eq_map_map_submonoid
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra.algebra_map_submonoid", "algebra_map", "fun_like.congr_fun", "is_localization.algebra_map_eq_map_map_submonoid" ]
If the square below commutes, the bottom map is uniquely specified: ``` R → S ↓ ↓ Rₘ → Sₘ ```
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_localization.lift_algebra_map_eq_algebra_map : @is_localization.lift R _ M Rₘ _ _ Sₘ _ _ (algebra_map R Sₘ) (is_localization.map_units_map_submonoid S Sₘ) = algebra_map Rₘ Sₘ
is_localization.lift_unique _ (λ x, (is_scalar_tower.algebra_map_apply _ _ _ _).symm)
lemma
is_localization.lift_algebra_map_eq_algebra_map
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "is_localization.lift", "is_localization.lift_unique", "is_localization.map_units_map_submonoid", "is_scalar_tower.algebra_map_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
localization_algebra_injective (hRS : function.injective (algebra_map R S)) : function.injective (@algebra_map Rₘ Sₘ _ _ (localization_algebra M S))
is_localization.map_injective_of_injective M Rₘ Sₘ hRS
lemma
localization_algebra_injective
ring_theory.localization
src/ring_theory/localization/basic.lean
[ "algebra.algebra.tower", "algebra.ring.equiv", "group_theory.monoid_localization", "ring_theory.ideal.basic", "ring_theory.non_zero_divisors", "tactic.ring_exp" ]
[ "algebra_map", "is_localization.map_injective_of_injective", "localization_algebra" ]
Injectivity of the underlying `algebra_map` descends to the algebra induced by localization.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_le : #L ≤ #R
begin classical, casesI fintype_or_infinite R, { exact cardinal.mk_le_of_surjective (is_artinian_ring.localization_surjective S _) }, erw [←cardinal.mul_eq_self $ cardinal.aleph_0_le_mk R], set f : R × R → L := λ aa, is_localization.mk' _ aa.1 (if h : aa.2 ∈ S then ⟨aa.2, h⟩ else 1), refine @cardinal.mk_le_...
lemma
is_localization.card_le
ring_theory.localization
src/ring_theory/localization/cardinality.lean
[ "set_theory.cardinal.ordinal", "ring_theory.artinian" ]
[ "cardinal.aleph_0_le_mk", "cardinal.mk_le_of_surjective", "fintype_or_infinite", "is_artinian_ring.localization_surjective", "is_localization.mk'", "is_localization.mk'_surjective", "set_like.eta" ]
A localization always has cardinality less than or equal to the base ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card (hS : S ≤ R⁰) : #R = #L
(cardinal.mk_le_of_injective (is_localization.injective L hS)).antisymm (card_le S)
lemma
is_localization.card
ring_theory.localization
src/ring_theory/localization/cardinality.lean
[ "set_theory.cardinal.ordinal", "ring_theory.artinian" ]
[ "cardinal.mk_le_of_injective", "is_localization.injective" ]
If you do not localize at any zero-divisors, localization preserves cardinality.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_fraction_ring [comm_ring K] [algebra R K]
is_localization (non_zero_divisors R) K
abbreviation
is_fraction_ring
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra", "comm_ring", "is_localization", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rat.is_fraction_ring : is_fraction_ring ℤ ℚ
{ map_units := begin rintro ⟨x, hx⟩, rw mem_non_zero_divisors_iff_ne_zero at hx, simpa only [eq_int_cast, is_unit_iff_ne_zero, int.cast_eq_zero, ne.def, subtype.coe_mk] using hx, end, surj := begin rintro ⟨n, d, hd, h⟩, refine ⟨⟨n, ⟨d, _⟩⟩, rat.mul_denom_eq_num⟩, rwa [m...
instance
rat.is_fraction_ring
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "eq_int_cast", "int.cast_eq_zero", "int.cast_inj", "int.coe_nat_ne_zero_iff_pos", "is_fraction_ring", "is_unit_iff_ne_zero", "mem_non_zero_divisors_iff_ne_zero", "mul_left_cancel₀", "subtype.coe_mk" ]
The cast from `int` to `rat` as a `fraction_ring`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_map_eq_zero_iff {x : R} : algebra_map R K x = 0 ↔ x = 0
to_map_eq_zero_iff _ (le_of_eq rfl)
lemma
is_fraction_ring.to_map_eq_zero_iff
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective : function.injective (algebra_map R K)
is_localization.injective _ (le_of_eq rfl)
theorem
is_fraction_ring.injective
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra_map", "is_localization.injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_inj {a b : R} : (↑a : K) = ↑b ↔ a = b
(is_fraction_ring.injective R K).eq_iff
lemma
is_fraction_ring.coe_inj
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "is_fraction_ring.injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_map_ne_zero_of_mem_non_zero_divisors [nontrivial R] {x : R} (hx : x ∈ non_zero_divisors R) : algebra_map R K x ≠ 0
is_localization.to_map_ne_zero_of_mem_non_zero_divisors _ le_rfl hx
lemma
is_fraction_ring.to_map_ne_zero_of_mem_non_zero_divisors
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra_map", "is_localization.to_map_ne_zero_of_mem_non_zero_divisors", "le_rfl", "non_zero_divisors", "nontrivial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_domain : is_domain K
is_domain_of_le_non_zero_divisors _ (le_refl (non_zero_divisors A))
theorem
is_fraction_ring.is_domain
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "is_domain", "non_zero_divisors" ]
A `comm_ring` `K` which is the localization of an integral domain `R` at `R - {0}` is an integral domain.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv (z : K) : K
if h : z = 0 then 0 else mk' K ↑(sec (non_zero_divisors A) z).2 ⟨(sec _ z).1, mem_non_zero_divisors_iff_ne_zero.2 $ λ h0, h $ eq_zero_of_fst_eq_zero (sec_spec (non_zero_divisors A) z) h0⟩
def
is_fraction_ring.inv
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "mk'", "non_zero_divisors" ]
The inverse of an element in the field of fractions of an integral domain.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_cancel (x : K) (hx : x ≠ 0) : x * is_fraction_ring.inv A x = 1
begin rw [is_fraction_ring.inv, dif_neg hx, ←is_unit.mul_left_inj (map_units K ⟨(sec _ x).1, mem_non_zero_divisors_iff_ne_zero.2 $ λ h0, hx $ eq_zero_of_fst_eq_zero (sec_spec (non_zero_divisors A) x) h0⟩), one_mul, mul_assoc], rw [mk'_spec, ←eq_mk'_iff_mul_eq], exact (mk'_sec _ x).symm end
lemma
is_fraction_ring.mul_inv_cancel
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "is_fraction_ring.inv", "mul_assoc", "mul_inv_cancel", "non_zero_divisors", "one_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_field : field K
{ inv := is_fraction_ring.inv A, mul_inv_cancel := is_fraction_ring.mul_inv_cancel A, inv_zero := begin change is_fraction_ring.inv A (0 : K) = 0, rw [is_fraction_ring.inv], exact dif_pos rfl end, .. is_fraction_ring.is_domain A, .. show comm_ring K, by apply_instance }
def
is_fraction_ring.to_field
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "comm_ring", "field", "inv_zero", "is_fraction_ring.inv", "is_fraction_ring.is_domain", "is_fraction_ring.mul_inv_cancel", "mul_inv_cancel" ]
A `comm_ring` `K` which is the localization of an integral domain `R` at `R - {0}` is a field. See note [reducible non-instances].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk'_mk_eq_div {r s} (hs : s ∈ non_zero_divisors A) : mk' K r ⟨s, hs⟩ = algebra_map A K r / algebra_map A K s
mk'_eq_iff_eq_mul.2 $ (div_mul_cancel (algebra_map A K r) (is_fraction_ring.to_map_ne_zero_of_mem_non_zero_divisors hs)).symm
lemma
is_fraction_ring.mk'_mk_eq_div
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra_map", "div_mul_cancel", "is_fraction_ring.to_map_ne_zero_of_mem_non_zero_divisors", "mk'", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk'_eq_div {r} (s : non_zero_divisors A) : mk' K r s = algebra_map A K r / algebra_map A K s
mk'_mk_eq_div s.2
lemma
is_fraction_ring.mk'_eq_div
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra_map", "mk'", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_surjective (z : K) : ∃ (x y : A) (hy : y ∈ non_zero_divisors A), algebra_map _ _ x / algebra_map _ _ y = z
let ⟨x, ⟨y, hy⟩, h⟩ := mk'_surjective (non_zero_divisors A) z in ⟨x, y, hy, by rwa mk'_eq_div at h⟩
lemma
is_fraction_ring.div_surjective
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra_map", "mk'_surjective", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit_map_of_injective (hg : function.injective g) (y : non_zero_divisors A) : is_unit (g y)
is_unit.mk0 (g y) $ show g.to_monoid_with_zero_hom y ≠ 0, from map_ne_zero_of_mem_non_zero_divisors g hg y.2
lemma
is_fraction_ring.is_unit_map_of_injective
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "is_unit", "is_unit.mk0", "map_ne_zero_of_mem_non_zero_divisors", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk'_eq_zero_iff_eq_zero [algebra R K] [is_fraction_ring R K] {x : R} {y : non_zero_divisors R} : mk' K x y = 0 ↔ x = 0
begin refine ⟨λ hxy, _, λ h, by rw [h, mk'_zero]⟩, { simp_rw [mk'_eq_zero_iff, mul_left_coe_non_zero_divisors_eq_zero_iff] at hxy, exact (exists_const _).mp hxy }, end
lemma
is_fraction_ring.mk'_eq_zero_iff_eq_zero
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra", "exists_const", "is_fraction_ring", "mk'", "mk'_zero", "mul_left_coe_non_zero_divisors_eq_zero_iff", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk'_eq_one_iff_eq {x : A} {y : non_zero_divisors A} : mk' K x y = 1 ↔ x = y
begin refine ⟨_, λ hxy, by rw [hxy, mk'_self']⟩, { intro hxy, have hy : (algebra_map A K) ↑y ≠ (0 : K) := is_fraction_ring.to_map_ne_zero_of_mem_non_zero_divisors y.property, rw [is_fraction_ring.mk'_eq_div, div_eq_one_iff_eq hy] at hxy, exact is_fraction_ring.injective A K hxy } end
lemma
is_fraction_ring.mk'_eq_one_iff_eq
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra_map", "div_eq_one_iff_eq", "is_fraction_ring.injective", "is_fraction_ring.mk'_eq_div", "is_fraction_ring.to_map_ne_zero_of_mem_non_zero_divisors", "mk'", "non_zero_divisors" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift (hg : injective g) : K →+* L
lift $ λ (y : non_zero_divisors A), is_unit_map_of_injective hg y
def
is_fraction_ring.lift
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "lift", "non_zero_divisors" ]
Given an integral domain `A` with field of fractions `K`, and an injective ring hom `g : A →+* L` where `L` is a field, we get a field hom sending `z : K` to `g x * (g y)⁻¹`, where `(x, y) : A × (non_zero_divisors A)` are such that `z = f x * (f y)⁻¹`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_algebra_map (hg : injective g) (x) : lift hg (algebra_map A K x) = g x
lift_eq _ _
lemma
is_fraction_ring.lift_algebra_map
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra_map", "lift" ]
Given an integral domain `A` with field of fractions `K`, and an injective ring hom `g : A →+* L` where `L` is a field, the field hom induced from `K` to `L` maps `x` to `g x` for all `x : A`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_mk' (hg : injective g) (x) (y : non_zero_divisors A) : lift hg (mk' K x y) = g x / g y
by simp only [mk'_eq_div, map_div₀, lift_algebra_map]
lemma
is_fraction_ring.lift_mk'
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "lift", "map_div₀", "mk'", "non_zero_divisors" ]
Given an integral domain `A` with field of fractions `K`, and an injective ring hom `g : A →+* L` where `L` is a field, field hom induced from `K` to `L` maps `f x / f y` to `g x / g y` for all `x : A, y ∈ non_zero_divisors A`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map {A B K L : Type*} [comm_ring A] [comm_ring B] [is_domain B] [comm_ring K] [algebra A K] [is_fraction_ring A K] [comm_ring L] [algebra B L] [is_fraction_ring B L] {j : A →+* B} (hj : injective j) : K →+* L
map L j (show non_zero_divisors A ≤ (non_zero_divisors B).comap j, from non_zero_divisors_le_comap_non_zero_divisors_of_injective j hj)
def
is_fraction_ring.map
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra", "comm_ring", "is_domain", "is_fraction_ring", "non_zero_divisors", "non_zero_divisors_le_comap_non_zero_divisors_of_injective" ]
Given integral domains `A, B` with fields of fractions `K`, `L` and an injective ring hom `j : A →+* B`, we get a field hom sending `z : K` to `g (j x) * (g (j y))⁻¹`, where `(x, y) : A × (non_zero_divisors A)` are such that `z = f x * (f y)⁻¹`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
field_equiv_of_ring_equiv [algebra B L] [is_fraction_ring B L] (h : A ≃+* B) : K ≃+* L
ring_equiv_of_ring_equiv K L h begin ext b, show b ∈ h.to_equiv '' _ ↔ _, erw [h.to_equiv.image_eq_preimage, set.preimage, set.mem_set_of_eq, mem_non_zero_divisors_iff_ne_zero, mem_non_zero_divisors_iff_ne_zero], exact h.symm.map_ne_zero_iff end
def
is_fraction_ring.field_equiv_of_ring_equiv
ring_theory.localization
src/ring_theory/localization/fraction_ring.lean
[ "algebra.algebra.tower", "ring_theory.localization.basic" ]
[ "algebra", "is_fraction_ring", "mem_non_zero_divisors_iff_ne_zero", "set.preimage" ]
Given integral domains `A, B` and localization maps to their fields of fractions `f : A →+* K, g : B →+* L`, an isomorphism `j : A ≃+* B` induces an isomorphism of fields of fractions `K ≃+* L`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83