From 999659039dc32f63b8069403b791035b4da5b577 Mon Sep 17 00:00:00 2001 From: poincare-duality Date: Wed, 14 Jun 2023 19:14:01 -0700 Subject: [PATCH] more stuff --- CommAlg/jayden(krull-dim-zero).lean | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/CommAlg/jayden(krull-dim-zero).lean b/CommAlg/jayden(krull-dim-zero).lean index 06dc873..eba40ab 100644 --- a/CommAlg/jayden(krull-dim-zero).lean +++ b/CommAlg/jayden(krull-dim-zero).lean @@ -19,7 +19,6 @@ import Mathlib.Util.PiNotation open PiNotation - namespace Ideal variable (R : Type _) [CommRing R] (P : PrimeSpectrum R) @@ -116,13 +115,30 @@ lemma power_zero_finite_length [Ideal.IsMaximal I] (h₁ : Ideal.FG I) [Module.F -- rcases power with ⟨n, npower⟩ -- how do I get a generating set? +open Finset -- Stacks Lemma 10.53.3: R is Artinian iff R has finitely many maximal ideals lemma Artinian_has_finite_max_ideal [IsArtinianRing R] : Finite (MaximalSpectrum R) := by by_contra infinite simp only [not_finite_iff_infinite] at infinite - + let m' : ℕ ↪ MaximalSpectrum R := Infinite.natEmbedding (MaximalSpectrum R) + have m'inj := m'.injective + let m'' : ℕ → Ideal R := fun n : ℕ ↦ ⨅ k ∈ range n, (m' k).asIdeal + have comaximal : ∀ i j : ℕ, i ≠ j → (m' i).asIdeal ⊔ (m' j).asIdeal = + (⊤ : Ideal R) := by + intro i j distinct + apply Ideal.IsMaximal.coprime_of_ne + sorry + sorry + -- by_contra equal + have : (m' i) ≠ (m' j) := by + exact Function.Injective.ne m'inj distinct + intro h + apply this + exact MaximalSpectrum.ext _ _ h + -- let g :`= Ideal.quotientInfRingEquivPiQuotient m' comaximal + -- Stacks Lemma 10.53.4: R Artinian => Jacobson ideal of R is nilpotent lemma Jacobson_of_Artinian_is_nilpotent