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preimage_specComap_zeroLocus_aux (f : R →+* S) (s : Set R) : f.specComap ⁻¹' zeroLocus s = zeroLocus (f '' s) := by ext x simp only [mem_zeroLocus, Set.image_subset_iff, Set.mem_preimage, mem_zeroLocus, Ideal.coe_comap] variable (f : R →+* S) @[simp]
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
preimage_specComap_zeroLocus_aux
null
specComap_asIdeal (y : PrimeSpectrum S) : (f.specComap y).asIdeal = Ideal.comap f y.asIdeal := rfl @[simp]
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
specComap_asIdeal
null
specComap_id : (RingHom.id R).specComap = fun x => x := rfl @[simp]
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
specComap_id
null
specComap_comp (f : R →+* S) (g : S →+* S') : (g.comp f).specComap = f.specComap.comp g.specComap := rfl
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
specComap_comp
null
specComap_comp_apply (f : R →+* S) (g : S →+* S') (x : PrimeSpectrum S') : (g.comp f).specComap x = f.specComap (g.specComap x) := rfl @[simp]
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
specComap_comp_apply
null
preimage_specComap_zeroLocus (s : Set R) : f.specComap ⁻¹' zeroLocus s = zeroLocus (f '' s) := preimage_specComap_zeroLocus_aux f s
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
preimage_specComap_zeroLocus
null
specComap_injective_of_surjective (f : R →+* S) (hf : Function.Surjective f) : Function.Injective f.specComap := fun x y h => PrimeSpectrum.ext (Ideal.comap_injective_of_surjective f hf (congr_arg PrimeSpectrum.asIdeal h : (f.specComap x).asIdeal = (f.specComap y).asIdeal))
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
specComap_injective_of_surjective
null
@[simps apply symm_apply] comapEquiv (e : R ≃+* S) : PrimeSpectrum R ≃o PrimeSpectrum S where toFun := e.symm.toRingHom.specComap invFun := e.toRingHom.specComap left_inv x := by rw [← specComap_comp_apply, RingEquiv.toRingHom_eq_coe, RingEquiv.toRingHom_eq_coe, RingEquiv.symm_comp] rfl right_inv x := by rw [← specComap_comp_apply, RingEquiv.toRingHom_eq_coe, RingEquiv.toRingHom_eq_coe, RingEquiv.comp_symm] rfl map_rel_iff' {I J} := Ideal.comap_le_comap_iff_of_surjective _ e.symm.surjective ..
def
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
comapEquiv
`RingHom.specComap` of an isomorphism of rings as an equivalence of their prime spectra.
@[simps] sigmaToPi : (Σ i, PrimeSpectrum (R i)) → PrimeSpectrum (Π i, R i) | ⟨i, p⟩ => (Pi.evalRingHom R i).specComap p
def
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
sigmaToPi
The canonical map from a disjoint union of prime spectra of commutative semirings to the prime spectrum of the product semiring. -/ /- TODO: show this is always a topological embedding (even when ι is infinite) and is a homeomorphism when ι is finite.
sigmaToPi_injective : (sigmaToPi R).Injective := fun ⟨i, p⟩ ⟨j, q⟩ eq ↦ by classical obtain rfl | ne := eq_or_ne i j · congr; ext x simpa using congr_arg (Function.update (0 : ∀ i, R i) i x ∈ ·.asIdeal) eq · refine (p.1.ne_top_iff_one.mp p.2.ne_top ?_).elim have : Function.update (1 : ∀ i, R i) j 0 ∈ (sigmaToPi R ⟨j, q⟩).asIdeal := by simp simpa [← eq, Function.update_of_ne ne] variable [Infinite ι] [∀ i, Nontrivial (R i)]
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
sigmaToPi_injective
null
exists_maximal_notMem_range_sigmaToPi_of_infinite : ∃ (I : Ideal (Π i, R i)) (_ : I.IsMaximal), ⟨I, inferInstance⟩ ∉ Set.range (sigmaToPi R) := by classical let J : Ideal (Π i, R i) := -- `J := Π₀ i, R i` is an ideal in `Π i, R i` { __ := AddMonoidHom.mrange DFinsupp.coeFnAddMonoidHom smul_mem' := by rintro r _ ⟨x, rfl⟩ refine ⟨.mk x.support fun i ↦ r i * x i, funext fun i ↦ show dite _ _ _ = _ from ?_⟩ simp_rw [DFinsupp.coeFnAddMonoidHom] refine dite_eq_left_iff.mpr fun h ↦ ?_ rw [DFinsupp.notMem_support_iff.mp h, mul_zero] } have ⟨I, max, le⟩ := J.exists_le_maximal <| (Ideal.ne_top_iff_one _).mpr <| by rintro ⟨x, hx⟩ have ⟨i, hi⟩ := x.support.exists_notMem simpa [DFinsupp.coeFnAddMonoidHom, DFinsupp.notMem_support_iff.mp hi] using congr_fun hx i refine ⟨I, max, fun ⟨⟨i, p⟩, eq⟩ ↦ ?_⟩ have : ⇑(DFinsupp.single i 1) ∉ (sigmaToPi R ⟨i, p⟩).asIdeal := by simpa using p.1.ne_top_iff_one.mp p.2.ne_top rw [eq] at this exact this (le ⟨.single i 1, rfl⟩) @[deprecated (since := "2025-05-24")] alias exists_maximal_nmem_range_sigmaToPi_of_infinite := exists_maximal_notMem_range_sigmaToPi_of_infinite
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
exists_maximal_notMem_range_sigmaToPi_of_infinite
An infinite product of nontrivial commutative semirings has a maximal ideal outside of the range of `sigmaToPi`, i.e. is not of the form `πᵢ⁻¹(𝔭)` for some prime `𝔭 ⊂ R i`, where `πᵢ : (Π i, R i) →+* R i` is the projection. For a complete description of all prime ideals, see https://math.stackexchange.com/a/1563190.
sigmaToPi_not_surjective_of_infinite : ¬ (sigmaToPi R).Surjective := fun surj ↦ have ⟨_, _, notMem⟩ := exists_maximal_notMem_range_sigmaToPi_of_infinite R (Set.range_eq_univ.mpr surj ▸ notMem) ⟨⟩
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
sigmaToPi_not_surjective_of_infinite
null
exists_comap_evalRingHom_eq {ι : Type*} {R : ι → Type*} [∀ i, CommRing (R i)] [Finite ι] (p : PrimeSpectrum (Π i, R i)) : ∃ (i : ι) (q : PrimeSpectrum (R i)), (Pi.evalRingHom R i).specComap q = p := by classical cases nonempty_fintype ι let e (i) : Π i, R i := Function.update 1 i 0 have H : ∏ i, e i = 0 := by ext j rw [Finset.prod_apply, Pi.zero_apply, Finset.prod_eq_zero (Finset.mem_univ j)] simp [e] obtain ⟨i, hi⟩ : ∃ i, e i ∈ p.asIdeal := by simpa [← H, Ideal.IsPrime.prod_mem_iff] using p.asIdeal.zero_mem let h₁ : Function.Surjective (Pi.evalRingHom R i) := RingHomSurjective.is_surjective have h₂ : RingHom.ker (Pi.evalRingHom R i) ≤ p.asIdeal := by intro x hx convert p.asIdeal.mul_mem_left x hi ext j by_cases hj : i = j · subst hj; simpa [e] · simp [e, Function.update_of_ne (.symm hj)] have : (p.asIdeal.map (Pi.evalRingHom R i)).comap (Pi.evalRingHom R i) = p.asIdeal := by rwa [Ideal.comap_map_of_surjective _ h₁, sup_eq_left] exact ⟨i, ⟨_, Ideal.map_isPrime_of_surjective h₁ h₂⟩, PrimeSpectrum.ext this⟩
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
exists_comap_evalRingHom_eq
null
sigmaToPi_bijective {ι : Type*} (R : ι → Type*) [∀ i, CommRing (R i)] [Finite ι] : Function.Bijective (sigmaToPi R) := by refine ⟨sigmaToPi_injective R, ?_⟩ intro q obtain ⟨i, q, rfl⟩ := exists_comap_evalRingHom_eq q exact ⟨⟨i, q⟩, rfl⟩
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
sigmaToPi_bijective
null
iUnion_range_specComap_comp_evalRingHom {ι : Type*} {R : ι → Type*} [∀ i, CommRing (R i)] [Finite ι] {S : Type*} [CommRing S] (f : S →+* Π i, R i) : ⋃ i, Set.range ((Pi.evalRingHom R i).comp f).specComap = Set.range f.specComap := by simp_rw [specComap_comp] apply subset_antisymm · exact Set.iUnion_subset fun _ ↦ Set.range_comp_subset_range _ _ · rintro _ ⟨p, rfl⟩ obtain ⟨i, p, rfl⟩ := exists_comap_evalRingHom_eq p exact Set.mem_iUnion_of_mem i ⟨p, rfl⟩
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
iUnion_range_specComap_comp_evalRingHom
null
image_specComap_zeroLocus_eq_zeroLocus_comap (hf : Surjective f) (I : Ideal S) : f.specComap '' zeroLocus I = zeroLocus (I.comap f) := by simp only [Set.ext_iff, Set.mem_image, mem_zeroLocus, SetLike.coe_subset_coe] refine fun p => ⟨?_, fun h_I_p => ?_⟩ · rintro ⟨p, hp, rfl⟩ a ha exact hp ha · have hp : ker f ≤ p.asIdeal := (Ideal.comap_mono bot_le).trans h_I_p refine ⟨⟨p.asIdeal.map f, Ideal.map_isPrime_of_surjective hf hp⟩, fun x hx => ?_, ?_⟩ · obtain ⟨x', rfl⟩ := hf x exact Ideal.mem_map_of_mem f (h_I_p hx) · ext x rw [specComap_asIdeal, Ideal.mem_comap, Ideal.mem_map_iff_of_surjective f hf] refine ⟨?_, fun hx => ⟨x, hx, rfl⟩⟩ rintro ⟨x', hx', heq⟩ rw [← sub_sub_cancel x' x] refine p.asIdeal.sub_mem hx' (hp ?_) rwa [mem_ker, map_sub, sub_eq_zero]
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
image_specComap_zeroLocus_eq_zeroLocus_comap
null
range_specComap_of_surjective (hf : Surjective f) : Set.range f.specComap = zeroLocus (ker f) := by rw [← Set.image_univ] convert image_specComap_zeroLocus_eq_zeroLocus_comap _ _ hf _ rw [zeroLocus_bot] variable {S}
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
range_specComap_of_surjective
null
noncomputable Ideal.primeSpectrumOrderIsoZeroLocusOfSurj (hf : Surjective f) {I : Ideal R} (hI : RingHom.ker f = I) : PrimeSpectrum S ≃o (PrimeSpectrum.zeroLocus (R := R) I) where toFun p := ⟨f.specComap p, hI.symm.trans_le (Ideal.ker_le_comap f)⟩ invFun := fun ⟨⟨p, _⟩, hp⟩ ↦ ⟨p.map f, p.map_isPrime_of_surjective hf (hI.trans_le hp)⟩ left_inv := by intro ⟨p, _⟩ simp only [PrimeSpectrum.mk.injEq] exact p.map_comap_of_surjective f hf right_inv := by intro ⟨⟨p, _⟩, hp⟩ simp only [Subtype.mk.injEq, PrimeSpectrum.mk.injEq] exact (p.comap_map_of_surjective f hf).trans <| sup_eq_left.mpr (hI.trans_le hp) map_rel_iff' {a b} := by change a.asIdeal.comap _ ≤ b.asIdeal.comap _ ↔ a ≤ b rw [← Ideal.map_le_iff_le_comap, Ideal.map_comap_of_surjective f hf, PrimeSpectrum.asIdeal_le_asIdeal]
def
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
Ideal.primeSpectrumOrderIsoZeroLocusOfSurj
Let `f : R →+* S` be a surjective ring homomorphism, then `Spec S` is order-isomorphic to `Z(I)` where `I = ker f`.
noncomputable Ideal.primeSpectrumQuotientOrderIsoZeroLocus (I : Ideal R) : PrimeSpectrum (R ⧸ I) ≃o (PrimeSpectrum.zeroLocus (R := R) I) := primeSpectrumOrderIsoZeroLocusOfSurj (Quotient.mk I) Quotient.mk_surjective I.mk_ker
def
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
Ideal.primeSpectrumQuotientOrderIsoZeroLocus
`Spec (R / I)` is order-isomorphic to `Z(I)`.
PrimeSpectrum.mem_range_comap_iff {p : PrimeSpectrum R} : p ∈ Set.range f.specComap ↔ (p.asIdeal.map f).comap f = p.asIdeal := by refine ⟨fun ⟨q, hq⟩ ↦ by simp [← hq], ?_⟩ rw [Ideal.comap_map_eq_self_iff_of_isPrime] rintro ⟨q, _, hq⟩ exact ⟨⟨q, inferInstance⟩, PrimeSpectrum.ext hq⟩ open TensorProduct
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
PrimeSpectrum.mem_range_comap_iff
`p` is in the image of `Spec S → Spec R` if and only if `p` extended to `S` and restricted back to `R` is `p`.
PrimeSpectrum.nontrivial_iff_mem_rangeComap {S : Type*} [CommRing S] [Algebra R S] (p : PrimeSpectrum R) : Nontrivial (p.asIdeal.ResidueField ⊗[R] S) ↔ p ∈ Set.range (algebraMap R S).specComap := by let k := p.asIdeal.ResidueField refine ⟨fun h ↦ ?_, fun h ↦ ?_⟩ · obtain ⟨m, hm⟩ := Ideal.exists_maximal (k ⊗[R] S) use (Algebra.TensorProduct.includeRight).specComap ⟨m, hm.isPrime⟩ ext : 1 rw [← PrimeSpectrum.specComap_comp_apply, ← Algebra.TensorProduct.includeLeftRingHom_comp_algebraMap, specComap_comp_apply] simp [Ideal.eq_bot_of_prime, k, ← RingHom.ker_eq_comap_bot] · obtain ⟨q, rfl⟩ := h let f : k ⊗[R] S →ₐ[R] q.asIdeal.ResidueField := Algebra.TensorProduct.lift (Ideal.ResidueField.mapₐ _ _ rfl) (IsScalarTower.toAlgHom _ _ _) (fun _ _ ↦ Commute.all ..) exact RingHom.domain_nontrivial f.toRingHom
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
PrimeSpectrum.nontrivial_iff_mem_rangeComap
A prime `p` is in the range of `Spec S → Spec R` if the fiber over `p` is nontrivial.
PrimeSpectrum.residueField_specComap (I : PrimeSpectrum R) : Set.range (algebraMap R I.asIdeal.ResidueField).specComap = {I} := by rw [Set.range_unique, Set.singleton_eq_singleton_iff] exact PrimeSpectrum.ext (Ideal.ext fun x ↦ Ideal.algebraMap_residueField_eq_zero)
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
PrimeSpectrum.residueField_specComap
null
IsLocalHom.of_specComap_surjective [CommSemiring R] [CommSemiring S] (f : R →+* S) (hf : Function.Surjective f.specComap) : IsLocalHom f where map_nonunit x hfx := by by_contra hx obtain ⟨p, hp, _⟩ := exists_max_ideal_of_mem_nonunits hx obtain ⟨⟨q, hqp⟩, hq⟩ := hf ⟨p, hp.isPrime⟩ simp only [PrimeSpectrum.mk.injEq] at hq exact hqp.ne_top (q.eq_top_of_isUnit_mem (q.mem_comap.mp (by rwa [hq])) hfx)
theorem
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Basic", "Mathlib.RingTheory.LocalRing.ResidueField.Ideal", "Mathlib.RingTheory.TensorProduct.Basic" ]
Mathlib/RingTheory/Spectrum/Prime/RingHom.lean
IsLocalHom.of_specComap_surjective
null
noncomputable PrimeSpectrum.tensorProductTo (x : PrimeSpectrum (S ⊗[R] T)) : PrimeSpectrum S × PrimeSpectrum T := ⟨comap (algebraMap _ _) x, comap Algebra.TensorProduct.includeRight.toRingHom x⟩ @[fun_prop]
def
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Topology", "Mathlib.RingTheory.SurjectiveOnStalks" ]
Mathlib/RingTheory/Spectrum/Prime/TensorProduct.lean
PrimeSpectrum.tensorProductTo
The canonical map from `Spec(S ⊗[R] T)` to the Cartesian product `Spec S × Spec T`.
PrimeSpectrum.continuous_tensorProductTo : Continuous (tensorProductTo R S T) := (comap _).2.prodMk (comap _).2 variable (hRT : (algebraMap R T).SurjectiveOnStalks) include hRT
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Topology", "Mathlib.RingTheory.SurjectiveOnStalks" ]
Mathlib/RingTheory/Spectrum/Prime/TensorProduct.lean
PrimeSpectrum.continuous_tensorProductTo
null
PrimeSpectrum.isEmbedding_tensorProductTo_of_surjectiveOnStalks_aux (p₁ p₂ : PrimeSpectrum (S ⊗[R] T)) (h : tensorProductTo R S T p₁ = tensorProductTo R S T p₂) : p₁ ≤ p₂ := by let g : T →+* S ⊗[R] T := Algebra.TensorProduct.includeRight.toRingHom intro x hxp₁ by_contra hxp₂ obtain ⟨t, r, a, ht, e⟩ := hRT.exists_mul_eq_tmul x (p₂.asIdeal.comap g) inferInstance have h₁ : a ⊗ₜ[R] t ∈ p₁.asIdeal := e ▸ p₁.asIdeal.mul_mem_left (1 ⊗ₜ[R] (r • t)) hxp₁ have h₂ : a ⊗ₜ[R] t ∉ p₂.asIdeal := e ▸ p₂.asIdeal.primeCompl.mul_mem ht hxp₂ rw [← mul_one a, ← one_mul t, ← Algebra.TensorProduct.tmul_mul_tmul] at h₁ h₂ have h₃ : t ∉ p₂.asIdeal.comap g := fun h ↦ h₂ (Ideal.mul_mem_left _ _ h) have h₄ : a ∉ p₂.asIdeal.comap (algebraMap S (S ⊗[R] T)) := fun h ↦ h₂ (Ideal.mul_mem_right _ _ h) replace h₃ : t ∉ p₁.asIdeal.comap g := by rwa [show p₁.asIdeal.comap g = p₂.asIdeal.comap g from congr($h.2.1)] replace h₄ : a ∉ p₁.asIdeal.comap (algebraMap S (S ⊗[R] T)) := by rwa [show p₁.asIdeal.comap (algebraMap S (S ⊗[R] T)) = p₂.asIdeal.comap _ from congr($h.1.1)] exact p₁.asIdeal.primeCompl.mul_mem h₄ h₃ h₁
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Topology", "Mathlib.RingTheory.SurjectiveOnStalks" ]
Mathlib/RingTheory/Spectrum/Prime/TensorProduct.lean
PrimeSpectrum.isEmbedding_tensorProductTo_of_surjectiveOnStalks_aux
null
PrimeSpectrum.isEmbedding_tensorProductTo_of_surjectiveOnStalks : IsEmbedding (tensorProductTo R S T) := by refine ⟨?_, fun p₁ p₂ e ↦ (isEmbedding_tensorProductTo_of_surjectiveOnStalks_aux R S T hRT p₁ p₂ e).antisymm (isEmbedding_tensorProductTo_of_surjectiveOnStalks_aux R S T hRT p₂ p₁ e.symm)⟩ let g : T →+* S ⊗[R] T := Algebra.TensorProduct.includeRight.toRingHom refine ⟨(continuous_tensorProductTo ..).le_induced.antisymm (isBasis_basic_opens.le_iff.mpr ?_)⟩ rintro _ ⟨f, rfl⟩ rw [@isOpen_iff_forall_mem_open] rintro J (hJ : f ∉ J.asIdeal) obtain ⟨t, r, a, ht, e⟩ := hRT.exists_mul_eq_tmul f (J.asIdeal.comap g) inferInstance refine ⟨_, ?_, ⟨_, (basicOpen a).2.prod (basicOpen t).2, rfl⟩, ?_⟩ · rintro x ⟨hx₁ : a ⊗ₜ[R] (1 : T) ∉ x.asIdeal, hx₂ : (1 : S) ⊗ₜ[R] t ∉ x.asIdeal⟩ (hx₃ : f ∈ x.asIdeal) apply x.asIdeal.primeCompl.mul_mem hx₁ hx₂ rw [Algebra.TensorProduct.tmul_mul_tmul, mul_one, one_mul, ← e] exact x.asIdeal.mul_mem_left _ hx₃ · have : a ⊗ₜ[R] (1 : T) * (1 : S) ⊗ₜ[R] t ∉ J.asIdeal := by rw [Algebra.TensorProduct.tmul_mul_tmul, mul_one, one_mul, ← e] exact J.asIdeal.primeCompl.mul_mem ht hJ rwa [J.isPrime.mul_mem_iff_mem_or_mem.not, not_or] at this
lemma
RingTheory
[ "Mathlib.RingTheory.Spectrum.Prime.Topology", "Mathlib.RingTheory.SurjectiveOnStalks" ]
Mathlib/RingTheory/Spectrum/Prime/TensorProduct.lean
PrimeSpectrum.isEmbedding_tensorProductTo_of_surjectiveOnStalks
null
zariskiTopology : TopologicalSpace (PrimeSpectrum R) := TopologicalSpace.ofClosed (Set.range PrimeSpectrum.zeroLocus) ⟨Set.univ, by simp⟩ (by intro Zs h rw [Set.sInter_eq_iInter] choose f hf using fun i : Zs => h i.prop simp only [← hf] exact ⟨_, zeroLocus_iUnion _⟩) (by rintro _ ⟨s, rfl⟩ _ ⟨t, rfl⟩ exact ⟨_, (union_zeroLocus s t).symm⟩)
instance
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
zariskiTopology
The Zariski topology on the prime spectrum of a commutative (semi)ring is defined via the closed sets of the topology: they are exactly those sets that are the zero locus of a subset of the ring.
isOpen_iff (U : Set (PrimeSpectrum R)) : IsOpen U ↔ ∃ s, Uᶜ = zeroLocus s := by simp only [@eq_comm _ Uᶜ]; rfl
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isOpen_iff
null
isClosed_iff_zeroLocus (Z : Set (PrimeSpectrum R)) : IsClosed Z ↔ ∃ s, Z = zeroLocus s := by rw [← isOpen_compl_iff, isOpen_iff, compl_compl]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosed_iff_zeroLocus
null
isClosed_iff_zeroLocus_ideal (Z : Set (PrimeSpectrum R)) : IsClosed Z ↔ ∃ I : Ideal R, Z = zeroLocus I := (isClosed_iff_zeroLocus _).trans ⟨fun ⟨s, hs⟩ => ⟨_, (zeroLocus_span s).substr hs⟩, fun ⟨I, hI⟩ => ⟨I, hI⟩⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosed_iff_zeroLocus_ideal
null
isClosed_iff_zeroLocus_radical_ideal (Z : Set (PrimeSpectrum R)) : IsClosed Z ↔ ∃ I : Ideal R, I.IsRadical ∧ Z = zeroLocus I := (isClosed_iff_zeroLocus_ideal _).trans ⟨fun ⟨I, hI⟩ => ⟨_, I.radical_isRadical, (zeroLocus_radical I).substr hI⟩, fun ⟨I, _, hI⟩ => ⟨I, hI⟩⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosed_iff_zeroLocus_radical_ideal
null
isClosed_zeroLocus (s : Set R) : IsClosed (zeroLocus s) := by rw [isClosed_iff_zeroLocus] exact ⟨s, rfl⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosed_zeroLocus
null
zeroLocus_vanishingIdeal_eq_closure (t : Set (PrimeSpectrum R)) : zeroLocus (vanishingIdeal t : Set R) = closure t := by rcases isClosed_iff_zeroLocus (closure t) |>.mp isClosed_closure with ⟨I, hI⟩ rw [subset_antisymm_iff, (isClosed_zeroLocus _).closure_subset_iff, hI, subset_zeroLocus_iff_subset_vanishingIdeal, (gc R).u_l_u_eq_u, ← subset_zeroLocus_iff_subset_vanishingIdeal, ← hI] exact ⟨subset_closure, subset_zeroLocus_vanishingIdeal t⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
zeroLocus_vanishingIdeal_eq_closure
null
vanishingIdeal_closure (t : Set (PrimeSpectrum R)) : vanishingIdeal (closure t) = vanishingIdeal t := zeroLocus_vanishingIdeal_eq_closure t ▸ (gc R).u_l_u_eq_u t
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
vanishingIdeal_closure
null
closure_singleton (x) : closure ({x} : Set (PrimeSpectrum R)) = zeroLocus x.asIdeal := by rw [← zeroLocus_vanishingIdeal_eq_closure, vanishingIdeal_singleton]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
closure_singleton
null
isClosed_singleton_iff_isMaximal (x : PrimeSpectrum R) : IsClosed ({x} : Set (PrimeSpectrum R)) ↔ x.asIdeal.IsMaximal := by rw [← closure_subset_iff_isClosed, ← zeroLocus_vanishingIdeal_eq_closure, vanishingIdeal_singleton] constructor <;> intro H · rcases x.asIdeal.exists_le_maximal x.2.1 with ⟨m, hm, hxm⟩ exact (congr_arg asIdeal (@H ⟨m, hm.isPrime⟩ hxm)) ▸ hm · exact fun p hp ↦ PrimeSpectrum.ext (H.eq_of_le p.2.1 hp).symm
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosed_singleton_iff_isMaximal
null
isRadical_vanishingIdeal (s : Set (PrimeSpectrum R)) : (vanishingIdeal s).IsRadical := by rw [← vanishingIdeal_closure, ← zeroLocus_vanishingIdeal_eq_closure, vanishingIdeal_zeroLocus_eq_radical] apply Ideal.radical_isRadical
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isRadical_vanishingIdeal
null
zeroLocus_eq_iff {I J : Ideal R} : zeroLocus (I : Set R) = zeroLocus J ↔ I.radical = J.radical := by constructor · intro h; simp_rw [← vanishingIdeal_zeroLocus_eq_radical, h] · intro h; rw [← zeroLocus_radical, h, zeroLocus_radical]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
zeroLocus_eq_iff
null
vanishingIdeal_anti_mono_iff {s t : Set (PrimeSpectrum R)} (ht : IsClosed t) : s ⊆ t ↔ vanishingIdeal t ≤ vanishingIdeal s := ⟨vanishingIdeal_anti_mono, fun h => by rw [← ht.closure_subset_iff, ← ht.closure_eq] convert ← zeroLocus_anti_mono_ideal h <;> apply zeroLocus_vanishingIdeal_eq_closure⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
vanishingIdeal_anti_mono_iff
null
vanishingIdeal_strict_anti_mono_iff {s t : Set (PrimeSpectrum R)} (hs : IsClosed s) (ht : IsClosed t) : s ⊂ t ↔ vanishingIdeal t < vanishingIdeal s := by rw [Set.ssubset_def, vanishingIdeal_anti_mono_iff hs, vanishingIdeal_anti_mono_iff ht, lt_iff_le_not_ge]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
vanishingIdeal_strict_anti_mono_iff
null
closedsEmbedding (R : Type*) [CommSemiring R] : (TopologicalSpace.Closeds <| PrimeSpectrum R)ᵒᵈ ↪o Ideal R := OrderEmbedding.ofMapLEIff (fun s => vanishingIdeal ↑(OrderDual.ofDual s)) fun s _ => (vanishingIdeal_anti_mono_iff s.2).symm
def
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
closedsEmbedding
The antitone order embedding of closed subsets of `Spec R` into ideals of `R`.
t1Space_iff_isField [IsDomain R] : T1Space (PrimeSpectrum R) ↔ IsField R := by refine ⟨?_, fun h => ?_⟩ · intro h have hbot : Ideal.IsPrime (⊥ : Ideal R) := Ideal.bot_prime exact Classical.not_not.1 (mt (Ring.ne_bot_of_isMaximal_of_not_isField <| (isClosed_singleton_iff_isMaximal _).1 (T1Space.t1 ⟨⊥, hbot⟩)) (by simp)) · refine ⟨fun x => (isClosed_singleton_iff_isMaximal x).2 ?_⟩ by_cases hx : x.asIdeal = ⊥ · letI := h.toSemifield exact hx.symm ▸ Ideal.bot_isMaximal · exact absurd h (Ring.not_isField_iff_exists_prime.2 ⟨x.asIdeal, ⟨hx, x.2⟩⟩) local notation "Z(" a ")" => zeroLocus (a : Set R)
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
t1Space_iff_isField
null
isIrreducible_zeroLocus_iff_of_radical (I : Ideal R) (hI : I.IsRadical) : IsIrreducible (zeroLocus (I : Set R)) ↔ I.IsPrime := by rw [Ideal.isPrime_iff, IsIrreducible] apply and_congr · rw [Set.nonempty_iff_ne_empty, Ne, zeroLocus_empty_iff_eq_top] · trans ∀ x y : Ideal R, Z(I) ⊆ Z(x) ∪ Z(y) → Z(I) ⊆ Z(x) ∨ Z(I) ⊆ Z(y) · simp_rw [isPreirreducible_iff_isClosed_union_isClosed, isClosed_iff_zeroLocus_ideal] constructor · rintro h x y exact h _ _ ⟨x, rfl⟩ ⟨y, rfl⟩ · rintro h _ _ ⟨x, rfl⟩ ⟨y, rfl⟩ exact h x y · simp_rw [← zeroLocus_inf, subset_zeroLocus_iff_le_vanishingIdeal, vanishingIdeal_zeroLocus_eq_radical, hI.radical] constructor · simp_rw [← SetLike.mem_coe, ← Set.singleton_subset_iff, ← Ideal.span_le, ← Ideal.span_singleton_mul_span_singleton] refine fun h x y h' => h _ _ ?_ rw [← hI.radical_le_iff] at h' ⊢ simpa only [Ideal.radical_inf, Ideal.radical_mul] using h' · simp_rw [or_iff_not_imp_left, SetLike.not_le_iff_exists] rintro h s t h' ⟨x, hx, hx'⟩ y hy exact h (h' ⟨Ideal.mul_mem_right _ _ hx, Ideal.mul_mem_left _ _ hy⟩) hx'
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isIrreducible_zeroLocus_iff_of_radical
null
isIrreducible_zeroLocus_iff (I : Ideal R) : IsIrreducible (zeroLocus (I : Set R)) ↔ I.radical.IsPrime := zeroLocus_radical I ▸ isIrreducible_zeroLocus_iff_of_radical _ I.radical_isRadical
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isIrreducible_zeroLocus_iff
null
isIrreducible_iff_vanishingIdeal_isPrime {s : Set (PrimeSpectrum R)} : IsIrreducible s ↔ (vanishingIdeal s).IsPrime := by rw [← isIrreducible_iff_closure, ← zeroLocus_vanishingIdeal_eq_closure, isIrreducible_zeroLocus_iff_of_radical _ (isRadical_vanishingIdeal s)]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isIrreducible_iff_vanishingIdeal_isPrime
null
vanishingIdeal_isIrreducible : vanishingIdeal (R := R) '' {s | IsIrreducible s} = {P | P.IsPrime} := Set.ext fun I ↦ ⟨fun ⟨_, hs, e⟩ ↦ e ▸ isIrreducible_iff_vanishingIdeal_isPrime.mp hs, fun h ↦ ⟨zeroLocus I, (isIrreducible_zeroLocus_iff_of_radical _ h.isRadical).mpr h, (vanishingIdeal_zeroLocus_eq_radical I).trans h.radical⟩⟩
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
vanishingIdeal_isIrreducible
null
vanishingIdeal_isClosed_isIrreducible : vanishingIdeal (R := R) '' {s | IsClosed s ∧ IsIrreducible s} = {P | P.IsPrime} := by refine (subset_antisymm ?_ ?_).trans vanishingIdeal_isIrreducible · exact Set.image_mono fun _ ↦ And.right rintro _ ⟨s, hs, rfl⟩ exact ⟨closure s, ⟨isClosed_closure, hs.closure⟩, vanishingIdeal_closure s⟩
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
vanishingIdeal_isClosed_isIrreducible
null
irreducibleSpace [IsDomain R] : IrreducibleSpace (PrimeSpectrum R) := by rw [irreducibleSpace_def, Set.top_eq_univ, ← zeroLocus_bot, isIrreducible_zeroLocus_iff] simpa using Ideal.bot_prime
instance
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
irreducibleSpace
null
quasiSober : QuasiSober (PrimeSpectrum R) := ⟨fun {S} h₁ h₂ => ⟨⟨_, isIrreducible_iff_vanishingIdeal_isPrime.1 h₁⟩, by rw [IsGenericPoint, closure_singleton, zeroLocus_vanishingIdeal_eq_closure, h₂.closure_eq]⟩⟩
instance
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
quasiSober
null
compactSpace : CompactSpace (PrimeSpectrum R) := by refine compactSpace_of_finite_subfamily_closed fun S S_closed S_empty ↦ ?_ choose I hI using fun i ↦ (isClosed_iff_zeroLocus_ideal (S i)).mp (S_closed i) simp_rw [hI, ← zeroLocus_iSup, zeroLocus_empty_iff_eq_top, ← top_le_iff] at S_empty ⊢ exact Ideal.isCompactElement_top.exists_finset_of_le_iSup _ _ S_empty
instance
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
compactSpace
The prime spectrum of a commutative (semi)ring is a compact topological space.
discreteTopology_iff_finite_and_krullDimLE_zero : DiscreteTopology (PrimeSpectrum R) ↔ Finite (PrimeSpectrum R) ∧ Ring.KrullDimLE 0 R := ⟨fun _ ↦ ⟨finite_of_compact_of_discrete, .mk₀ fun I h ↦ isClosed_singleton_iff_isMaximal ⟨I, h⟩ |>.mp <| discreteTopology_iff_forall_isClosed.mp ‹_› _⟩, fun ⟨_, _⟩ ↦ .of_finite_of_isClosed_singleton fun p ↦ (isClosed_singleton_iff_isMaximal p).mpr inferInstance⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
discreteTopology_iff_finite_and_krullDimLE_zero
The prime spectrum of a commutative semiring has discrete Zariski topology iff it is finite and the semiring has Krull dimension zero or is trivial.
discreteTopology_iff_finite_isMaximal_and_sInf_le_nilradical : letI s := {I : Ideal R | I.IsMaximal} DiscreteTopology (PrimeSpectrum R) ↔ Finite s ∧ sInf s ≤ nilradical R := by rw [discreteTopology_iff_finite_and_krullDimLE_zero, Ring.krullDimLE_zero_iff, (equivSubtype R).finite_iff, ← Set.coe_setOf, Set.finite_coe_iff, Set.finite_coe_iff] refine ⟨fun h ↦ ⟨h.1.subset fun _ h ↦ h.isPrime, nilradical_eq_sInf R ▸ sInf_le_sInf h.2⟩, fun ⟨fin, le⟩ ↦ ?_⟩ have hpm (I : Ideal R) (hI : I.IsPrime): I.IsMaximal := by replace le := le.trans (nilradical_le_prime I) rw [← fin.coe_toFinset, ← Finset.inf_id_eq_sInf, hI.inf_le'] at le have ⟨M, hM, hMI⟩ := le rw [fin.mem_toFinset] at hM rwa [← hM.eq_of_le hI.1 hMI] exact ⟨fin.subset hpm, hpm⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
discreteTopology_iff_finite_isMaximal_and_sInf_le_nilradical
The prime spectrum of a semiring has discrete Zariski topology iff there are only finitely many maximal ideals and their intersection is contained in the nilradical.
discreteTopology_of_toLocalization_surjective (surj : Function.Surjective (toPiLocalization R)) : DiscreteTopology (PrimeSpectrum R) := discreteTopology_iff_finite_and_krullDimLE_zero.mpr ⟨finite_of_toPiLocalization_surjective surj, .mk₀ fun I prime ↦ isMaximal_of_toPiLocalization_surjective surj ⟨I, prime⟩⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
discreteTopology_of_toLocalization_surjective
null
comap (f : R →+* S) : C(PrimeSpectrum S, PrimeSpectrum R) where toFun := f.specComap continuous_toFun := by simp only [continuous_iff_isClosed, isClosed_iff_zeroLocus] rintro _ ⟨s, rfl⟩ exact ⟨_, preimage_specComap_zeroLocus_aux f s⟩
def
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap
The continuous function between prime spectra of commutative (semi)rings induced by a ring homomorphism.
coe_comap (f : R →+* S) : comap f = f.specComap := rfl
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
coe_comap
null
comap_apply (f : R →+* S) (x) : comap f x = f.specComap x := rfl variable (f : R →+* S) @[simp]
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_apply
null
comap_asIdeal (y : PrimeSpectrum S) : (comap f y).asIdeal = Ideal.comap f y.asIdeal := rfl @[simp]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_asIdeal
null
comap_id : comap (RingHom.id R) = ContinuousMap.id _ := by ext rfl @[simp]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_id
null
comap_comp (f : R →+* S) (g : S →+* S') : comap (g.comp f) = (comap f).comp (comap g) := rfl
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_comp
null
comap_comp_apply (f : R →+* S) (g : S →+* S') (x : PrimeSpectrum S') : PrimeSpectrum.comap (g.comp f) x = (PrimeSpectrum.comap f) (PrimeSpectrum.comap g x) := rfl @[simp]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_comp_apply
null
preimage_comap_zeroLocus (s : Set R) : comap f ⁻¹' zeroLocus s = zeroLocus (f '' s) := preimage_specComap_zeroLocus_aux f s
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
preimage_comap_zeroLocus
null
comap_injective_of_surjective (f : R →+* S) (hf : Function.Surjective f) : Function.Injective (comap f) := fun _ _ h => specComap_injective_of_surjective _ hf h variable (S)
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_injective_of_surjective
null
localization_specComap_injective [Algebra R S] (M : Submonoid R) [IsLocalization M S] : Function.Injective (algebraMap R S).specComap := by intro p q h replace h := _root_.congr_arg (fun x : PrimeSpectrum R => Ideal.map (algebraMap R S) x.asIdeal) h dsimp only [RingHom.specComap] at h rw [IsLocalization.map_comap M S, IsLocalization.map_comap M S] at h ext1 exact h
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
localization_specComap_injective
null
localization_specComap_range [Algebra R S] (M : Submonoid R) [IsLocalization M S] : Set.range (algebraMap R S).specComap = { p | Disjoint (M : Set R) p.asIdeal } := by refine Set.ext fun x ↦ ⟨?_, fun h ↦ ?_⟩ · rintro ⟨p, rfl⟩ exact ((IsLocalization.isPrime_iff_isPrime_disjoint ..).mp p.2).2 · use ⟨x.asIdeal.map (algebraMap R S), IsLocalization.isPrime_of_isPrime_disjoint M S _ x.2 h⟩ ext1 exact IsLocalization.comap_map_of_isPrime_disjoint M S _ x.2 h
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
localization_specComap_range
null
localization_comap_isInducing [Algebra R S] (M : Submonoid R) [IsLocalization M S] : IsInducing (comap (algebraMap R S)) := by refine ⟨TopologicalSpace.ext_isClosed fun Z ↦ ?_⟩ simp_rw [isClosed_induced_iff, isClosed_iff_zeroLocus, @eq_comm _ _ (zeroLocus _), exists_exists_eq_and, preimage_comap_zeroLocus] constructor · rintro ⟨s, rfl⟩ refine ⟨(Ideal.span s).comap (algebraMap R S), ?_⟩ rw [← zeroLocus_span, ← zeroLocus_span s, ← Ideal.map, IsLocalization.map_comap M S] · rintro ⟨s, rfl⟩ exact ⟨_, rfl⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
localization_comap_isInducing
null
localization_comap_injective [Algebra R S] (M : Submonoid R) [IsLocalization M S] : Function.Injective (comap (algebraMap R S)) := fun _ _ h => localization_specComap_injective S M h
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
localization_comap_injective
null
localization_comap_isEmbedding [Algebra R S] (M : Submonoid R) [IsLocalization M S] : IsEmbedding (comap (algebraMap R S)) := ⟨localization_comap_isInducing S M, localization_comap_injective S M⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
localization_comap_isEmbedding
null
localization_comap_range [Algebra R S] (M : Submonoid R) [IsLocalization M S] : Set.range (comap (algebraMap R S)) = { p | Disjoint (M : Set R) p.asIdeal } := localization_specComap_range .. open Function RingHom
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
localization_comap_range
null
comap_isInducing_of_surjective (hf : Surjective f) : IsInducing (comap f) where eq_induced := by simp only [TopologicalSpace.ext_iff, ← isClosed_compl_iff, isClosed_iff_zeroLocus, isClosed_induced_iff] refine fun s => ⟨fun ⟨F, hF⟩ => ⟨zeroLocus (f ⁻¹' F), ⟨f ⁻¹' F, rfl⟩, by rw [preimage_comap_zeroLocus, Function.Surjective.image_preimage hf, hF]⟩, ?_⟩ rintro ⟨-, ⟨F, rfl⟩, hF⟩ exact ⟨f '' F, hF.symm.trans (preimage_comap_zeroLocus f F)⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_isInducing_of_surjective
null
isEmbedding_comap_of_surjective (hf : Surjective f) : IsEmbedding (comap f) := (isEmbedding_iff _).2 ⟨comap_isInducing_of_surjective _ _ hf, comap_injective_of_surjective f hf⟩
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isEmbedding_comap_of_surjective
The embedding has closed range if the domain (and therefore the codomain) is a ring, see `PrimeSpectrum.isClosedEmbedding_comap_of_surjective`. On the other hand, `comap (Nat.castRingHom (ZMod 2))` does not have closed range.
homeomorphOfRingEquiv (e : R ≃+* S) : PrimeSpectrum R ≃ₜ PrimeSpectrum S where toFun := comap (e.symm : S →+* R) invFun := comap (e : R →+* S) left_inv _ := (comap_comp_apply ..).symm.trans (by simp) right_inv _ := (comap_comp_apply ..).symm.trans (by simp)
def
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
homeomorphOfRingEquiv
Homeomorphism between prime spectra induced by an isomorphism of semirings.
isHomeomorph_comap_of_bijective {f : R →+* S} (hf : Function.Bijective f) : IsHomeomorph (comap f) := (homeomorphOfRingEquiv (.ofBijective f hf)).symm.isHomeomorph
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isHomeomorph_comap_of_bijective
null
comap_singleton_isClosed_of_surjective (f : R →+* S) (hf : Function.Surjective f) (x : PrimeSpectrum S) (hx : IsClosed ({x} : Set (PrimeSpectrum S))) : IsClosed ({comap f x} : Set (PrimeSpectrum R)) := haveI : x.asIdeal.IsMaximal := (isClosed_singleton_iff_isMaximal x).1 hx (isClosed_singleton_iff_isMaximal _).2 (Ideal.comap_isMaximal_of_surjective f hf)
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_singleton_isClosed_of_surjective
null
image_comap_zeroLocus_eq_zeroLocus_comap (hf : Surjective f) (I : Ideal S) : comap f '' zeroLocus I = zeroLocus (I.comap f) := image_specComap_zeroLocus_eq_zeroLocus_comap _ f hf I
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
image_comap_zeroLocus_eq_zeroLocus_comap
null
range_comap_of_surjective (hf : Surjective f) : Set.range (comap f) = zeroLocus (ker f) := range_specComap_of_surjective _ f hf
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
range_comap_of_surjective
null
comap_quotientMk_bijective_of_le_nilradical {I : Ideal R} (hle : I ≤ nilradical R) : Function.Bijective (comap <| Ideal.Quotient.mk I) := by refine ⟨comap_injective_of_surjective _ Ideal.Quotient.mk_surjective, ?_⟩ simpa [← Set.range_eq_univ, range_comap_of_surjective _ _ Ideal.Quotient.mk_surjective, zeroLocus_eq_univ_iff]
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
comap_quotientMk_bijective_of_le_nilradical
null
isClosed_range_comap_of_surjective (hf : Surjective f) : IsClosed (Set.range (comap f)) := by rw [range_comap_of_surjective _ f hf] exact isClosed_zeroLocus _
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosed_range_comap_of_surjective
null
isClosedEmbedding_comap_of_surjective (hf : Surjective f) : IsClosedEmbedding (comap f) where toIsInducing := comap_isInducing_of_surjective S f hf injective := comap_injective_of_surjective f hf isClosed_range := isClosed_range_comap_of_surjective S f hf
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosedEmbedding_comap_of_surjective
null
primeSpectrumProd_symm_inl (x) : (primeSpectrumProd R S).symm (.inl x) = comap (RingHom.fst R S) x := by ext; simp [Ideal.prod]
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
primeSpectrumProd_symm_inl
null
primeSpectrumProd_symm_inr (x) : (primeSpectrumProd R S).symm (.inr x) = comap (RingHom.snd R S) x := by ext; simp [Ideal.prod]
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
primeSpectrumProd_symm_inr
null
range_comap_fst : Set.range (comap (RingHom.fst R S)) = zeroLocus (RingHom.ker (RingHom.fst R S)) := by refine Set.ext fun p ↦ ⟨?_, fun h ↦ ?_⟩ · rintro ⟨I, hI, rfl⟩; exact Ideal.comap_mono bot_le obtain ⟨p, hp, eq⟩ | ⟨p, hp, eq⟩ := p.1.ideal_prod_prime.mp p.2 · exact ⟨⟨p, hp⟩, PrimeSpectrum.ext <| by simpa [Ideal.prod] using eq.symm⟩ · refine (hp.ne_top <| (Ideal.eq_top_iff_one _).mpr ?_).elim simpa [eq] using h (show (0, 1) ∈ RingHom.ker (RingHom.fst R S) by simp)
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
range_comap_fst
null
range_comap_snd : Set.range (comap (RingHom.snd R S)) = zeroLocus (RingHom.ker (RingHom.snd R S)) := by refine Set.ext fun p ↦ ⟨?_, fun h ↦ ?_⟩ · rintro ⟨I, hI, rfl⟩; exact Ideal.comap_mono bot_le obtain ⟨p, hp, eq⟩ | ⟨p, hp, eq⟩ := p.1.ideal_prod_prime.mp p.2 · refine (hp.ne_top <| (Ideal.eq_top_iff_one _).mpr ?_).elim simpa [eq] using h (show (1, 0) ∈ RingHom.ker (RingHom.snd R S) by simp) · exact ⟨⟨p, hp⟩, PrimeSpectrum.ext <| by simpa [Ideal.prod] using eq.symm⟩
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
range_comap_snd
null
isClosedEmbedding_comap_fst : IsClosedEmbedding (comap (RingHom.fst R S)) := (isClosedEmbedding_iff _).mpr ⟨isEmbedding_comap_of_surjective _ _ Prod.fst_surjective, by simp_rw [range_comap_fst, isClosed_zeroLocus]⟩
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosedEmbedding_comap_fst
null
isClosedEmbedding_comap_snd : IsClosedEmbedding (comap (RingHom.snd R S)) := (isClosedEmbedding_iff _).mpr ⟨isEmbedding_comap_of_surjective _ _ Prod.snd_surjective, by simp_rw [range_comap_snd, isClosed_zeroLocus]⟩
lemma
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isClosedEmbedding_comap_snd
null
noncomputable primeSpectrumProdHomeo : PrimeSpectrum (R × S) ≃ₜ PrimeSpectrum R ⊕ PrimeSpectrum S := by refine ((primeSpectrumProd R S).symm.toHomeomorphOfIsInducing ?_).symm refine (IsClosedEmbedding.of_continuous_injective_isClosedMap ?_ (Equiv.injective _) ?_).isInducing · rw [continuous_sum_dom] simp only [Function.comp_def, primeSpectrumProd_symm_inl, primeSpectrumProd_symm_inr] exact ⟨(comap _).2, (comap _).2⟩ · simp_rw [isClosedMap_sum, primeSpectrumProd_symm_inl, primeSpectrumProd_symm_inr] exact ⟨isClosedEmbedding_comap_fst.isClosedMap, isClosedEmbedding_comap_snd.isClosedMap⟩
def
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
primeSpectrumProdHomeo
The prime spectrum of `R × S` is homeomorphic to the disjoint union of `PrimeSpectrum R` and `PrimeSpectrum S`.
basicOpen (r : R) : TopologicalSpace.Opens (PrimeSpectrum R) where carrier := { x | r ∉ x.asIdeal } is_open' := ⟨{r}, Set.ext fun _ => Set.singleton_subset_iff.trans <| Classical.not_not.symm⟩ @[simp]
def
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen
`basicOpen r` is the open subset containing all prime ideals not containing `r`.
mem_basicOpen (f : R) (x : PrimeSpectrum R) : x ∈ basicOpen f ↔ f ∉ x.asIdeal := Iff.rfl
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
mem_basicOpen
null
isOpen_basicOpen {a : R} : IsOpen (basicOpen a : Set (PrimeSpectrum R)) := (basicOpen a).isOpen @[simp]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isOpen_basicOpen
null
basicOpen_eq_zeroLocus_compl (r : R) : (basicOpen r : Set (PrimeSpectrum R)) = (zeroLocus {r})ᶜ := Set.ext fun x => by simp only [SetLike.mem_coe, mem_basicOpen, Set.mem_compl_iff, mem_zeroLocus, Set.singleton_subset_iff] @[simp]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_eq_zeroLocus_compl
null
basicOpen_one : basicOpen (1 : R) = ⊤ := TopologicalSpace.Opens.ext <| by simp @[simp]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_one
null
basicOpen_zero : basicOpen (0 : R) = ⊥ := TopologicalSpace.Opens.ext <| by simp
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_zero
null
basicOpen_le_basicOpen_iff (f g : R) : basicOpen f ≤ basicOpen g ↔ f ∈ (Ideal.span ({g} : Set R)).radical := by rw [← SetLike.coe_subset_coe, basicOpen_eq_zeroLocus_compl, basicOpen_eq_zeroLocus_compl, Set.compl_subset_compl, zeroLocus_subset_zeroLocus_singleton_iff]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_le_basicOpen_iff
null
basicOpen_le_basicOpen_iff_algebraMap_isUnit {f g : R} [Algebra R S] [IsLocalization.Away f S] : basicOpen f ≤ basicOpen g ↔ IsUnit (algebraMap R S g) := by simp_rw [basicOpen_le_basicOpen_iff, Ideal.mem_radical_iff, Ideal.mem_span_singleton, IsLocalization.Away.algebraMap_isUnit_iff f]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_le_basicOpen_iff_algebraMap_isUnit
null
basicOpen_mul (f g : R) : basicOpen (f * g) = basicOpen f ⊓ basicOpen g := TopologicalSpace.Opens.ext <| by simp [zeroLocus_singleton_mul]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_mul
null
basicOpen_mul_le_left (f g : R) : basicOpen (f * g) ≤ basicOpen f := by rw [basicOpen_mul f g] exact inf_le_left
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_mul_le_left
null
basicOpen_mul_le_right (f g : R) : basicOpen (f * g) ≤ basicOpen g := by rw [basicOpen_mul f g] exact inf_le_right @[simp]
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_mul_le_right
null
basicOpen_pow (f : R) (n : ℕ) (hn : 0 < n) : basicOpen (f ^ n) = basicOpen f := TopologicalSpace.Opens.ext <| by simpa using zeroLocus_singleton_pow f n hn
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
basicOpen_pow
null
isTopologicalBasis_basic_opens : TopologicalSpace.IsTopologicalBasis (Set.range fun r : R => (basicOpen r : Set (PrimeSpectrum R))) := by apply TopologicalSpace.isTopologicalBasis_of_isOpen_of_nhds · rintro _ ⟨r, rfl⟩ exact isOpen_basicOpen · rintro p U hp ⟨s, hs⟩ rw [← compl_compl U, Set.mem_compl_iff, ← hs, mem_zeroLocus, Set.not_subset] at hp obtain ⟨f, hfs, hfp⟩ := hp refine ⟨basicOpen f, ⟨f, rfl⟩, hfp, ?_⟩ rw [← Set.compl_subset_compl, ← hs, basicOpen_eq_zeroLocus_compl, compl_compl] exact zeroLocus_anti_mono (Set.singleton_subset_iff.mpr hfs)
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
isTopologicalBasis_basic_opens
null
eq_biUnion_of_isOpen {s : Set (PrimeSpectrum R)} (hs : IsOpen s) : s = ⋃ (r : R) (_ : ↑(basicOpen r) ⊆ s), basicOpen r := (isTopologicalBasis_basic_opens.open_eq_sUnion' hs).trans <| by aesop
theorem
RingTheory
[ "Mathlib.Algebra.Order.Ring.Idempotent", "Mathlib.Order.Heyting.Hom", "Mathlib.RingTheory.Finiteness.Ideal", "Mathlib.RingTheory.Ideal.GoingUp", "Mathlib.RingTheory.Ideal.MinimalPrime.Localization", "Mathlib.RingTheory.KrullDimension.Basic", "Mathlib.RingTheory.Localization.Algebra", "Mathlib.RingTheo...
Mathlib/RingTheory/Spectrum/Prime/Topology.lean
eq_biUnion_of_isOpen
null