OAI/AlgebraicGeometry/SurfaceCones/CartierFactorization.lean

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60 declarations, 0 contain sorry, 0 declared as axioms

Cartier lattices on completed surface cones

This development accompanies A Complete Local Domain without a Small Cohen–Macaulay Module (OpenAI, 2026).

  1. lemma OAI.ActualCartier.global_power_sandwich_factorization line 36

    Source documentation

    The two cleared maps are inverse up to the indicated ideal power. Torsion freeness extends the equality from the puncture to the whole scheme.

    lemma global_power_sandwich_factorization
        (n : ℕ) {M N : Y.Modules} [N.IsFinitePresentation]
        (hN : ∀ U, Module.IsTorsionFree (Y.sheaf.obj.obj U) (N.val.obj U))
        (e : M.over (ActualOpenSupport.complement g) ≅
          N.over (ActualOpenSupport.complement g))
        (f : (power (tensorLeft Y.sheaf (idealSheaf g)) n).obj M ⟶ N)
        (a : (power (tensorLeft Y.sheaf (idealSheaf g)) n).obj N ⟶ M)
        (hf : f.over (ActualOpenSupport.complement g) =
          ((powerAction (tensorLeft Y.sheaf (idealSheaf g))
            (idealAction Y.sheaf (idealι g)) n).app M).over
              (ActualOpenSupport.complement g) ≫ e.hom)
        (ha : a.over (ActualOpenSupport.complement g) =
    …

    Mentions: OAI.ActualOpenSupport.complement, OAI.ActualCartier.idealSheaf, OAI.ActualCartier.idealι

  2. lemma OAI.ActualCartier.idealMultiple_isZero_of_raw_factorization line 94

    Source documentation

    An ideal-power factorization annihilates the coherent quotient by the same exponent.

    lemma idealMultiple_isZero_of_raw_factorization
        {S : ShortComplex (Coh Y)} (hS : S.ShortExact) (n : ℕ)
        (a : (power (tensorLeft Y.sheaf (idealSheaf g)) n).obj S.X₂.obj ⟶ S.X₁.obj)
        (ha : a ≫ S.f.hom =
          (powerAction (tensorLeft Y.sheaf (idealSheaf g))
            (idealAction Y.sheaf (idealι g)) n).app S.X₂.obj) :
        IsZero (idealMultiple g d n S.X₃) := by
    …

    Mentions: OAI.ActualCartier.idealSheaf, OAI.ActualCartier.idealι, OAI.ActualCartier.idealMultiple

  3. lemma OAI.ActualCartier.exists_cleared_lattice_twice_bound line 119

    Source documentation

    The coherent lattice construction with the twice-clearing exponent, conormal-layer epimorphisms and divisor Grothendieck identity.

    lemma exists_cleared_lattice_twice_bound
        (M N : Y.Modules) [M.IsFinitePresentation] [N.IsFinitePresentation]
        (hM : ∀ U, Module.IsTorsionFree (Y.sheaf.obj.obj U) (M.val.obj U))
        (hN : ∀ U, Module.IsTorsionFree (Y.sheaf.obj.obj U) (N.val.obj U))
        (e : M.over (ActualOpenSupport.complement g) ≅
          N.over (ActualOpenSupport.complement g)) :
        let L : Coh Y := ⟨N, inferInstance⟩
    …

    Mentions: OAI.ActualOpenSupport.complement

  4. def OAI.ActualCartier.coherentFree line 171

    Source documentation

    The finite free coherent module sheaf.

    def coherentFree (Y : Scheme.{0}) (I : Type) [Finite I] : Coh Y :=
    …
  5. lemma OAI.ActualCartier.free_sections_torsionFree line 177

    Source documentation

    On an integral scheme, the finite free sheaf is sectionwise torsion free, including empty opens.

    lemma free_sections_torsionFree (Y : Scheme.{0}) [IsIntegral Y]
        (I : Type) [Finite I] (U : Y.Opensᵒᵖ) :
        Module.IsTorsionFree (Y.sheaf.obj.obj U)
          ((SheafOfModules.free (R := Y.ringCatSheaf) I).val.obj U) := by
    …
  6. def OAI.ActualCartier.restriction_freeIso line 192

    Source documentation

    The coherent restriction used by the Cartier resolution sends the finite free sheaf to the same finite free sheaf on the divisor.

    def restriction_freeIso (I : Type) [Finite I] :
        (restriction g d).obj (coherentFree Y I) ≅ coherentFree X I :=
    …

    Mentions: OAI.ActualCartier.restriction, OAI.ActualCartier.coherentFree

  7. def OAI.ActualCartier.freeTwistedLayerQuotient line 205

    Source documentation

    The quotient map from the jth conormal twist of O_D^N to the jth quotient layer.

    def freeTwistedLayerQuotient {Q : Coh Y} {I : Type} [Finite I]
        (q : coherentFree Y I ⟶ Q) (j : ℕ) :
        (power (conormalFunctor g d) j).obj (coherentFree X I) ⟶ layer g d j Q :=
    …

    Mentions: OAI.ActualCartier.coherentFree, OAI.ActualCartier.conormalFunctor, OAI.ActualCartier.layer

  8. instance OAI.ActualCartier.freeTwistedLayerQuotient_epi line 211
  9. lemma OAI.ActualCartier.exists_free_cleared_lattice line 221

    Source documentation

    The sheaf-theoretic content of the divisor lattice construction for the finite free ambient lattice: a fixed puncture trivialization constructs the embedding, the finite twice-bound filtration, the divisor K₀ identity, and all the required quotients of conormal-twisted free sheaves.

    lemma exists_free_cleared_lattice [CompactSpace Y] [IsIntegral Y]
        (M : Y.Modules) [M.IsFinitePresentation]
        (hM : ∀ U, Module.IsTorsionFree (Y.sheaf.obj.obj U) (M.val.obj U))
        (N : ℕ)
        (e : M.over (ActualOpenSupport.complement g) ≅
          (SheafOfModules.free (R := Y.ringCatSheaf) (Fin N)).over
    …

    Mentions: OAI.ActualOpenSupport.complement

  10. lemma OAI.SourceZeroSections.seriesOrigin_kernel line 264
  11. lemma OAI.SourceZeroSections.seriesOrigin_range_compl line 273
  12. lemma OAI.SourceZeroSections.completedPlaneZero_range line 285
  13. lemma OAI.SourceZeroSections.planeComplement_eq line 302
  14. def OAI.SourceConeMorphism.modelPushforwardComplementFreeIso line 313
  15. def OAI.SourceConeMorphism.modelPushforwardOverFreeIso line 320

    Source documentation

    The slice-site framing for the generic lattice construction.

    def modelPushforwardOverFreeIso :
        (modelPushforward M).over (ActualOpenSupport.complement completedPlaneZero) ≅
          (SheafOfModules.free (R := V.ringCatSheaf) (basisIndex M hdepth)).over
    …

    Mentions: OAI.ActualOpenSupport.complement, OAI.SourceConeMorphism.basisIndex

  16. def OAI.SourceZeroSections.planeIdealChartIso line 343
  17. def OAI.SourceZeroSections.planeIdealLine line 353
  18. lemma OAI.SourceZeroSections.planeIdeal_coherent line 357
  19. instance OAI.SourceConeMorphism.sourcePlane_noetherian line 377
  20. instance OAI.SourceConeMorphism.sourceV_compact line 384
  21. instance OAI.SourceConeMorphism.basisIndex_fintype line 394
  22. abbrev OAI.SourceConeMorphism.sourceFreeRank line 395
  23. lemma OAI.SourceConeMorphism.sourceFreeRank_pos line 397
  24. def OAI.SourceConeMorphism.modelPushforwardOverFinIso line 404
  25. theorem OAI.SourceConeMorphism.exists_source_free_lattice line 415

    Source documentation

    Coherent lattice, finite conormal layers, K₀ identity, and quotients of conormal-twisted free sheaves for the finite pushforward. Every premise of the reused lattice theorem is supplied by the source.

    theorem exists_source_free_lattice :
        ∃ k : ℕ, ∀ n : ℕ, k ≤ n →
          ∃ a : clearedLattice completedPlaneZero planeIdealLine n (modelPushforward M) ⟶
              coherentFree V (Fin (sourceFreeRank M hdepth)),
            Mono a ∧
            ((cohInclusion V).map a).over (ActualOpenSupport.complement completedPlaneZero) =
              ((powerAction (tensorLeft V.sheaf (idealSheaf completedPlaneZero))
                (idealAction V.sheaf (idealι completedPlaneZero)) n).app (modelPushforward M)).over
                  (ActualOpenSupport.complement completedPlaneZero) ≫
                    (modelPushforwardOverFinIso M hdepth).hom ∧
            IsZero (idealMultiple completedPlaneZero planeIdealLine (n + n) (cokernel a)) ∧
            cls ((restriction completedPlaneZero planeIdealLine).obj
    …

    Mentions: OAI.SourceConeMorphism.sourceFreeRank, OAI.ActualOpenSupport.complement, OAI.SourceConeMorphism.modelPushforwardOverFinIso

  26. instance OAI.SourceConeMorphism.sourceSurface_noetherian line 445
  27. abbrev OAI.SourceConeMorphism.sourceRestriction line 448
  28. abbrev OAI.SourceConeMorphism.coherentModel line 449
  29. def OAI.SourceConeMorphism.sourceRestrictionIso line 452
  30. lemma OAI.SourceConeMorphism.modelRestriction_torsionFree line 456
  31. abbrev OAI.SourceConeMorphism.elementaryTransform line 464
  32. lemma OAI.SourceConeMorphism.elementaryTransform_torsionFree line 468
  33. lemma OAI.SourceConeMorphism.elementaryTransform_restriction_torsionFree line 478

    Source documentation

    The divisor restriction of an elementary transform is torsion-free when the chosen quotient is torsion-free.

    lemma elementaryTransform_restriction_torsionFree
        {B : Coh W} {G : Coh ExplicitCone.projectiveSurface}
        (q : sourceRestriction.obj B ⟶ G) [Epi q]
        (hB : ∀ U, Module.IsTorsionFree (W.sheaf.obj.obj U) (B.obj.val.obj U))
        (hP : ∀ U, Module.IsTorsionFree (ExplicitCone.projectiveSurface.sheaf.obj.obj U)
          ((sourceRestriction.obj B).obj.val.obj U))
        (hG : ∀ U, Module.IsTorsionFree (ExplicitCone.projectiveSurface.sheaf.obj.obj U)
          (G.obj.val.obj U))
        (U : ExplicitCone.projectiveSurface.Opensᵒᵖ) :
        Module.IsTorsionFree (ExplicitCone.projectiveSurface.sheaf.obj.obj U)
          ((sourceRestriction.obj (elementaryTransform q)).obj.val.obj U) := by
    …

    Mentions: OAI.ExplicitCone.projectiveSurface, OAI.SourceConeMorphism.elementaryTransform

  34. lemma OAI.SourceConeMorphism.elementaryTransform_puncture line 500
  35. abbrev OAI.SourceConeMorphism.sourceFramedOpen line 517
  36. lemma OAI.SourceConeMorphism.sourceZero_preimage_framed line 518
  37. structure OAI.SourceConeMorphism.ExtensionState line 523
  38. def OAI.SourceConeMorphism.ExtensionState.initial line 534
  39. def OAI.SourceConeMorphism.ExtensionState.transform line 542

    Source documentation

    The elementary transform constructs another admissible extension and preserves its punctured framing.

    def transform (B : ExtensionState M) {G : Coh ExplicitCone.projectiveSurface}
        (q : sourceRestriction.obj B.sheaf ⟶ G) [Epi q]
        (hG : ∀ U, Module.IsTorsionFree (ExplicitCone.projectiveSurface.sheaf.obj.obj U)
          (G.obj.val.obj U)) : ExtensionState M where
    …

    Mentions: OAI.SourceConeMorphism.ExtensionState, OAI.ExplicitCone.projectiveSurface

  40. def OAI.SourceConeMorphism.ExtensionState.pushforward line 556
  41. lemma OAI.SourceConeMorphism.ExtensionState.pushforward_torsionFree line 558
  42. def OAI.SourceConeMorphism.ExtensionState.pushforwardFraming line 565
  43. def OAI.SourceConeMorphism.ExtensionState.pushforwardOverFinIso line 574
  44. theorem OAI.SourceConeMorphism.ExtensionState.exists_free_lattice line 606

    Source documentation

    The exact coherent K₀ statement and conormal-twisted quotient layers needed by the lattice inequality, for any constructed extension.

    theorem exists_free_lattice (B : ExtensionState M) :
        ∃ k : ℕ, ∀ n : ℕ, k ≤ n →
          ∃ a : clearedLattice completedPlaneZero planeIdealLine n B.pushforward.obj ⟶
              coherentFree V (Fin (sourceFreeRank M hdepth)),
            Mono a ∧
            ((cohInclusion V).map a).over (ActualOpenSupport.complement completedPlaneZero) =
              ((powerAction (tensorLeft V.sheaf (idealSheaf completedPlaneZero))
                (idealAction V.sheaf (idealι completedPlaneZero)) n).app B.pushforward.obj).over
                  (ActualOpenSupport.complement completedPlaneZero) ≫
                    (B.pushforwardOverFinIso hdepth).hom ∧
            IsZero (idealMultiple completedPlaneZero planeIdealLine (n + n) (cokernel a)) ∧
            cls ((restriction completedPlaneZero planeIdealLine).obj
    …

    Mentions: OAI.SourceConeMorphism.ExtensionState, OAI.SourceConeMorphism.sourceFreeRank, OAI.ActualOpenSupport.complement

  45. def OAI.SourceConeMorphism.ExtensionState.restrictionPushforwardIso line 639
  46. lemma OAI.SourceConeMorphism.ExtensionState.restrictionPushforward_class line 648
  47. lemma OAI.ActualMateUnit.chosen_units line 667
  48. lemma OAI.ActualMateUnit.three_iso_chain line 682
  49. lemma OAI.ActualCartier.structure_comp line 703
  50. lemma OAI.ActualCartier.structure_congr line 712
  51. lemma OAI.ActualCartier.structure_square line 723
  52. lemma OAI.ActualCartier.pullbackUnit_adj line 738
  53. lemma OAI.ActualCartier.baseChange_structure line 747
  54. lemma OAI.ActualCartier.restrictionPullbackIso_unit line 773
  55. lemma OAI.ActualCartier.coherent_adjUnit_epi line 784
  56. lemma OAI.ActualCartier.structureMap_epi line 797
  57. lemma OAI.ActualRightExactIdeal.kernelComparison_epi line 820
  58. def OAI.ActualRightExactIdeal.comparison line 829
  59. instance OAI.ActualRightExactIdeal.comparison_epi line 834
  60. lemma OAI.ActualRightExactIdeal.comparison_ι line 842