diff --git a/CommAlg/jayden(krull-dim-zero).lean b/CommAlg/jayden(krull-dim-zero).lean index 0646bcb..bdb3bf9 100644 --- a/CommAlg/jayden(krull-dim-zero).lean +++ b/CommAlg/jayden(krull-dim-zero).lean @@ -4,15 +4,15 @@ import Mathlib.RingTheory.Noetherian import Mathlib.Order.KrullDimension import Mathlib.RingTheory.Artinian import Mathlib.RingTheory.Ideal.Quotient +import Mathlib.RingTheory.Nilpotent import Mathlib.AlgebraicGeometry.PrimeSpectrum.Basic - import Mathlib.AlgebraicGeometry.PrimeSpectrum.Maximal import Mathlib.Data.Finite.Defs - import Mathlib.Order.Height import Mathlib.RingTheory.DedekindDomain.Basic import Mathlib.RingTheory.Localization.AtPrime import Mathlib.Order.ConditionallyCompleteLattice.Basic +import Mathlib.Algebra.Ring.Pi -- copy from krull.lean; the name of Krull dimension for rings is changed to krullDim' since krullDim already exists in the librrary namespace Ideal @@ -26,21 +26,9 @@ noncomputable def krullDim' (R : Type) [CommRing R] : WithBot ℕ∞ := ⨆ (I : -- Stacks Lemma 10.60.5: R is Artinian iff R is Noetherian of dimension 0 lemma dim_zero_Noetherian_iff_Artinian (R : Type _) [CommRing R] : - IsNoetherianRing R ∧ krullDim' R = 0 ↔ IsArtinianRing R := by + IsNoetherianRing R ∧ krullDim' R = 0 ↔ IsArtinianRing R := by sorry -variable {R : Type _} [CommRing R] - --- Repeats the definition by Monalisa -noncomputable def length : krullDim (Submodule _ _) - - --- The following is Stacks Lemma 10.60.5 -lemma dim_zero_Noetherian_iff_Artinian (R : Type _) [CommRing R] : - IsNoetherianRing R ∧ krull_dim R = 0 ↔ IsArtinianRing R := by - - sorry - #check IsNoetherianRing #check krullDim @@ -58,7 +46,25 @@ lemma IsArtinian_iff_finite_length : IsArtinianRing R ↔ ∃ n : ℕ, length R lemma IsArtinian_iff_finite_max_ideal : IsArtinianRing R ↔ Finite (MaximalSpectrum R) := by sorry -- Stacks Lemma 10.53.4: R Artinian => Jacobson ideal of R is nilpotent -lemma Jacobson_of_Artinian_is_nilpotent : Is +lemma Jacobson_of_Artinian_is_nilpotent : IsArtinianRing R → IsNilpotent (Ideal.jacobson (⊤ : Ideal R)) := by sorry + + +-- Stacks Definition 10.32.1: An ideal is locally nilpotent +-- if every element is nilpotent +namespace Ideal +class IsLocallyNilpotent (I : Ideal R) : Prop := + h : ∀ x ∈ I, IsNilpotent x + +end Ideal + +#check Ideal.IsLocallyNilpotent + +-- Stacks Lemma 10.53.5: If R has finitely many maximal ideals and +-- locally nilpotent Jacobson radical, then R is the product of its localizations at +-- its maximal ideals. Also, all primes are maximal + +lemma product_of_localization_at_maximal_ideal : Finite (MaximalSpectrum R) + ∧ Ideal.IsLocallyNilpotent (Ideal.jacobson (⊤ : Ideal R)) → Localization.AtPrime R I @@ -70,8 +76,6 @@ end something open something --- The following is Stacks Lemma 10.53.6 -lemma IsArtinian_iff_finite_length : IsArtinianRing R ↔ ∃ n : ℕ, length R R ≤ n := by sorry