diff --git a/comm_alg/jayden(krull-dim-zero).lean b/comm_alg/jayden(krull-dim-zero).lean index 7be91c5..e084f18 100644 --- a/comm_alg/jayden(krull-dim-zero).lean +++ b/comm_alg/jayden(krull-dim-zero).lean @@ -1,28 +1,60 @@ import Mathlib.RingTheory.Ideal.Basic +import Mathlib.RingTheory.JacobsonIdeal import Mathlib.RingTheory.Noetherian import Mathlib.Order.KrullDimension import Mathlib.RingTheory.Artinian import Mathlib.RingTheory.Ideal.Quotient import Mathlib.AlgebraicGeometry.PrimeSpectrum.Basic +import Mathlib.AlgebraicGeometry.PrimeSpectrum.Maximal +import Mathlib.Data.Finite.Defs -variable {R : Type _} [CommRing R] +import Mathlib.Order.Height +import Mathlib.RingTheory.DedekindDomain.Basic +import Mathlib.RingTheory.Localization.AtPrime +import Mathlib.Order.ConditionallyCompleteLattice.Basic --- Repeats the definition by Monalisa -noncomputable def length : krullDim (Submodule _ _) +-- copy from krull.lean; the name of Krull dimension for rings is changed to krullDim' since krullDim already exists in the librrary +namespace Ideal +variable (R : Type _) [CommRing R] (I : PrimeSpectrum R) --- The following is Stacks Lemma 10.60.5 +noncomputable def height : ℕ∞ := Set.chainHeight {J : PrimeSpectrum R | J < I} + +noncomputable def krullDim' (R : Type) [CommRing R] : WithBot ℕ∞ := ⨆ (I : PrimeSpectrum R), height R I +-- copy ends + +-- 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 ∧ krull_dim R = 0 ↔ IsArtinianRing R := by + IsNoetherianRing R ∧ krullDim' R = 0 ↔ IsArtinianRing R := by sorry #check IsNoetherianRing --- The following is Stacks Lemma 10.53.6 +#check krullDim + +-- Repeats the definition of the length of a module by Monalisa +variable (M : Type _) [AddCommMonoid M] [Module R M] + +noncomputable def length := krullDim (Submodule R M) + +#check length +-- Stacks Lemma 10.53.6: R is Artinian iff R has finite length as an R-mod lemma IsArtinian_iff_finite_length : IsArtinianRing R ↔ ∃ n : ℕ, length R R ≤ n := by sorry +-- Stacks Lemma 10.53.3: R is Artinian iff R has finitely many maximal ideals +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 +-- how to use namespace + +namespace something + +end something + +open something