diff --git a/CommAlg/final_hil_pol.lean b/CommAlg/final_hil_pol.lean index 7176de2..ace2a1b 100644 --- a/CommAlg/final_hil_pol.lean +++ b/CommAlg/final_hil_pol.lean @@ -4,6 +4,14 @@ import Mathlib.Algebra.Module.GradedModule import Mathlib.RingTheory.Ideal.AssociatedPrime import Mathlib.RingTheory.Artinian import Mathlib.Order.Height +import Mathlib.RingTheory.Ideal.Quotient +import Mathlib.RingTheory.SimpleModule +import CommAlg.krull + + +#check Ideal.dim_field_eq_zero +#check Ideal.domain_dim_zero.isField +#check Ideal.Quotient.isDomain_iff_prime -- Setting for "library_search" @@ -67,15 +75,17 @@ instance tada3 (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) [∀ i, AddCommGr -- Definition of a Hilbert function of a graded module section + noncomputable def hilbert_function (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓜 i)] [DirectSum.GCommRing 𝒜] [DirectSum.Gmodule 𝒜 𝓜] (hilb : ℤ → ℤ) := ∀ i, hilb i = (ENat.toNat (length (𝒜 0) (𝓜 i))) -noncomputable def dimensionring { A: Type _} - [CommRing A] := krullDim (PrimeSpectrum A) - noncomputable def dimensionmodule ( A : Type _) (M : Type _) - [CommRing A] [AddCommGroup M] [Module A M] := krullDim (PrimeSpectrum (A ⧸ ((⊤ : Submodule A M).annihilator)) ) + [CommRing A] [AddCommGroup M] [Module A M] := Ideal.krullDim (A ⧸ ((⊤ : Submodule A M).annihilator)) + + +lemma equaldim ( A : Type _) [CommRing A] (I : Ideal A): dimensionmodule (A) (A ⧸ I) = Ideal.krullDim (A ⧸ I) := by +sorry end @@ -121,39 +131,79 @@ def Component_of_graded_as_addsubgroup (𝒜 : ℤ → Type _) sorry -def graded_morphism (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) (𝓝 : ℤ → Type _) +def graded_ring_morphism (𝒜 : ℤ → Type _) (ℬ : ℤ → Type _) +[∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (ℬ i)] +[DirectSum.GCommRing 𝒜] [DirectSum.GCommRing ℬ] (f : (⨁ i, 𝒜 i) →+* (⨁ i, ℬ i)) := ∀ i, ∀ (r : 𝒜 i), ∀ j, (j ≠ i → f (DirectSum.of _ i r) j = 0) + +def graded_module_morphism (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) (𝓝 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓜 i)] [∀ i, AddCommGroup (𝓝 i)] -[DirectSum.GCommRing 𝒜] [DirectSum.Gmodule 𝒜 𝓜][DirectSum.Gmodule 𝒜 𝓝] (f : (⨁ i, 𝓜 i) → (⨁ i, 𝓝 i)) : ∀ i, ∀ (r : 𝓜 i), ∀ j, (j ≠ i → f (DirectSum.of _ i r) j = 0) ∧ (IsLinearMap (⨁ i, 𝒜 i) f) := by sorry +[DirectSum.GCommRing 𝒜] [DirectSum.Gmodule 𝒜 𝓜][DirectSum.Gmodule 𝒜 𝓝] (f : (⨁ i, 𝓜 i) → (⨁ i, 𝓝 i)) := ∀ i, ∀ (r : 𝓜 i), ∀ j, (j ≠ i → f (DirectSum.of _ i r) j = 0) ∧ (IsLinearMap (⨁ i, 𝒜 i) f) - -def graded_submodule -(𝒜 : ℤ → Type _) (𝓜 : ℤ → Type u) (𝓝 : ℤ → Type u) +def graded_module_isomorphism (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) (𝓝 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓜 i)] [∀ i, AddCommGroup (𝓝 i)] [DirectSum.GCommRing 𝒜] [DirectSum.Gmodule 𝒜 𝓜][DirectSum.Gmodule 𝒜 𝓝] -(opn : Submodule (⨁ i, 𝒜 i) (⨁ i, 𝓜 i)) (opnis : opn = (⨁ i, 𝓝 i)) (i : ℤ ) - : ∃(piece : Submodule (𝒜 0) (𝓜 i)), piece = 𝓝 i := by - sorry +(f : (⨁ i, 𝓜 i) → (⨁ i, 𝓝 i)) +:= (graded_module_morphism 𝒜 𝓜 𝓝 f) ∧ (Function.Bijective f) + +def graded_ring_isomorphism (𝒜 : ℤ → Type _) (𝓑 : ℤ → Type _) +[∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓑 i)] +[DirectSum.GCommRing 𝒜] [DirectSum.GCommRing 𝓑] +(f : (⨁ i, 𝒜 i) →+* (⨁ i, 𝓑 i)) +:= (graded_ring_morphism 𝒜 𝓑 f) ∧ (Function.Bijective f) + +def graded_ring_isomorphic (𝒜 : ℤ → Type _) (𝓑 : ℤ → Type _) +[∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓑 i)] +[DirectSum.GCommRing 𝒜] [DirectSum.GCommRing 𝓑] := ∃ (f : (⨁ i, 𝒜 i) →+* (⨁ i, 𝓑 i)),graded_ring_isomorphism 𝒜 𝓑 f + + + +-- def graded_submodule +-- (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) (𝓝 : ℤ → Type _) +-- [∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓜 i)] [∀ i, AddCommGroup (𝓝 i)] +-- [DirectSum.GCommRing 𝒜] [DirectSum.Gmodule 𝒜 𝓜][DirectSum.Gmodule 𝒜 𝓝] +-- (h (⨁ i, 𝓝 i) : Submodule (⨁ i, 𝒜 i) (⨁ i, 𝓜 i)) : +-- Prop := +-- ∃ (piece : Submodule (𝒜 0) (𝓜 i)), piece = 𝓝 i end +class DirectSum.GalgebrA + (𝒜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [DirectSum.GCommRing 𝒜] + (𝓜 : ℤ → Type _) [∀ i, AddCommGroup (𝓜 i)] [DirectSum.GCommRing 𝓜] + extends DirectSum.Gmodule 𝒜 𝓜 + +def graded_algebra_morphism (𝒜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [DirectSum.GCommRing 𝒜] + (𝓜 : ℤ → Type _) [∀ i, AddCommGroup (𝓜 i)] [DirectSum.GCommRing 𝓜] [DirectSum.GalgebrA 𝒜 𝓜] + (𝓝 : ℤ → Type _) [∀ i, AddCommGroup (𝓝 i)] [DirectSum.GCommRing 𝓝] [DirectSum.GalgebrA 𝒜 𝓝] + (f : (⨁ i, 𝓜 i) →+* (⨁ i, 𝓝 i)) := (graded_ring_morphism 𝓜 𝓝 f) ∧ (graded_module_morphism 𝒜 𝓜 𝓝 f) +-- @Quotient of a graded ring R by a graded ideal p is a graded R-alg, preserving each component - --- @Quotient of a graded ring R by a graded ideal p is a graded R-Mod, preserving each component -instance Quotient_of_graded_is_graded +instance Quotient_of_graded_gradedring (𝒜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [DirectSum.GCommRing 𝒜] (p : Ideal (⨁ i, 𝒜 i)) (hp : Ideal.IsHomogeneous' 𝒜 p) - : DirectSum.Gmodule 𝒜 (fun i => (𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i)) := by + : DirectSum.GCommRing (fun i => (𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i)) := by + sorry + +instance Quotient_of_graded_is_gradedalg +(𝒜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [DirectSum.GCommRing 𝒜] +(p : Ideal (⨁ i, 𝒜 i)) (hp : Ideal.IsHomogeneous' 𝒜 p) + : DirectSum.GalgebrA 𝒜 (fun i => (𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i)) := by + sorry + +lemma Quotient_of_graded_ringiso (𝒜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [DirectSum.GCommRing 𝒜](p : Ideal (⨁ i, 𝒜 i)) (hp : Ideal.IsHomogeneous' 𝒜 p) +(hm : 𝓜 = (fun i => (𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i))) +: Nonempty ((⨁ i, (𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i)) ≃+* ((⨁ i, (𝒜 i))⧸p)) := by sorry -- If A_0 is Artinian and local, then A is graded local lemma Graded_local_if_zero_component_Artinian_and_local (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓜 i)] -[DirectSum.GCommRing 𝒜] [DirectSum.Gmodule 𝒜 𝓜] (art: IsArtinianRing (𝒜 0)) (loc : LocalRing (𝒜 0)) : ∃ ( I : Ideal ((⨁ i, 𝒜 i))),(HomogeneousMax 𝒜 I) := by +[DirectSum.GCommRing 𝒜] [DirectSum.Gmodule 𝒜 𝓜] (art: IsArtinianRing (𝒜 0)) (loc : LocalRing (𝒜 0)) : ∃! ( I : Ideal ((⨁ i, 𝒜 i))),(HomogeneousMax 𝒜 I) := by sorry @@ -225,20 +275,67 @@ theorem Hilbert_polynomial_d_0 (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) [ sorry --- (reduced version) [BH, 4.1.3] when d = 0 --- If M is a finite graed R-Mod of dimension zero, and M = R⧸ 𝓅 for a graded prime ideal 𝓅, then the Hilbert function H(M, n) = 0 for n >> 0 +#check Ideal.dim_field_eq_zero +#check Ideal.domain_dim_zero.isField +--#check Quotient.isDomain_iff_prime + +#check DirectSum + +-- f (g a) = f (g b) + +-- DirectSum _ (fun i => ...) = DirectSum _ (fun i => ...) + theorem Hilbert_polynomial_d_0_reduced (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓜 i)] -[DirectSum.GCommRing 𝒜] -[DirectSum.Gmodule 𝒜 𝓜] (st: StandardGraded 𝒜) (art: IsArtinianRing (𝒜 0)) (loc : LocalRing (𝒜 0)) +[DirectSum.GCommRing 𝒜] [DirectSum.GCommRing 𝓜] +[DirectSum.GalgebrA 𝒜 𝓜] (st: StandardGraded 𝒜) (art: IsArtinianRing (𝒜 0)) (loc : LocalRing (𝒜 0)) (fingen : IsNoetherian (⨁ i, 𝒜 i) (⨁ i, 𝓜 i)) (findim : dimensionmodule (⨁ i, 𝒜 i) (⨁ i, 𝓜 i) = 0) (hilb : ℤ → ℤ) (Hhilb : hilbert_function 𝒜 𝓜 hilb) -(p : Ideal (⨁ i, 𝒜 i)) (hp : Ideal.IsHomogeneous' 𝒜 p) -(hm : 𝓜 = (fun i => (𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i))) -: (∃ (N : ℤ), ∀ (n : ℤ), n ≥ N → hilb n = 0) := by - sorry - +(p : Ideal (⨁ i, 𝒜 i)) (hp : Ideal.IsHomogeneous' 𝒜 p) (hq : HomogeneousPrime 𝒜 p) +(hm : ∀ i, 𝓜 i = ((𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i))) +: (∃ (N : ℤ), ∀ (n : ℤ), n ≥ N → hilb n = 0) := by + let 𝓜' := fun i => (𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i) + have h : 𝓜 = 𝓜' := by + ext i + exact hm i + subst h + set R := ⨁ i, 𝒜 i + have : (⨁ i, 𝓜' i )= ⨁ i, ((𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i)) := by + rfl + +--have h1 : Nonempty ((⨁ i, 𝓜 i) ≃+* (R⧸p)) := by + +-- apply Quotient_of_graded_ringiso 𝒜 p hp +-- have : Ideal.krullDim (R ⧸ p) = 0 := by +-- calc 0 = dimensionmodule (⨁ i, 𝒜 i) (⨁ i, 𝓜 i) := by apply findim +-- _ = dimensionmodule (R) (R ⧸ p) := by apply h1 +-- _ = Ideal.krullDim (R_mod_p) := by apply equaldim +-- sorry + +lemma + +-- (reduced version) [BH, 4.1.3] when d = 0 +-- If M is a finite graed R-Mod of dimension zero, and M = R⧸ 𝓅 for a graded prime ideal 𝓅, then the Hilbert function H(M, n) = 0 for n >> 0 +-- theorem Hilbert_polynomial_d_0_reduced +-- (𝒜 : ℤ → Type _) (𝓜 : ℤ → Type _) [∀ i, AddCommGroup (𝒜 i)] [∀ i, AddCommGroup (𝓜 i)] +-- [DirectSum.GCommRing 𝒜] [DirectSum.GCommRing 𝓜] +-- [DirectSum.GalgebrA 𝒜 𝓜] (st: StandardGraded 𝒜) (art: IsArtinianRing (𝒜 0)) (loc : LocalRing (𝒜 0)) +-- (fingen : IsNoetherian (⨁ i, 𝒜 i) (⨁ i, 𝓜 i)) +-- (findim : dimensionmodule (⨁ i, 𝒜 i) (⨁ i, 𝓜 i) = 0) +-- (hilb : ℤ → ℤ) (Hhilb : hilbert_function 𝒜 𝓜 hilb) +-- (p : Ideal (⨁ i, 𝒜 i)) (hp : Ideal.IsHomogeneous' 𝒜 p) (hq : HomogeneousPrime 𝒜 p) +-- (hm : 𝓜 = (fun i => (𝒜 i)⧸(Component_of_graded_as_addsubgroup 𝒜 p hp i))) +-- : (∃ (N : ℤ), ∀ (n : ℤ), n ≥ N → hilb n = 0) := by +-- set R := ⨁ i, 𝒜 i +-- have h := (Ideal.Quotient.isDomain_iff_prime p).mpr hq.1 +-- have h1 : Nonempty ((⨁ i, 𝓜 i)) ≃+* (R⧸p)) := by +-- apply Quotient_of_graded_ringiso 𝒜 p hp +-- have : Ideal.krullDim (R ⧸ p) = 0 := by +-- calc 0 = dimensionmodule (⨁ i, 𝒜 i) (⨁ i, 𝓜 i) := by apply findim +-- _ = dimensionmodule (R) (R ⧸ p) := by apply h1 +-- _ = Ideal.krullDim (R_mod_p) := by apply equaldim +-- sorry