Module

FiniteAffineSectionSubmodule.lean

Nyll.SchemeTheory.Modules.FiniteAffineSectionSubmodule
4 declarations indexed from sourceView source ↗

Finite quasicoherent submodules containing finite affine-local generators

For each selected affine open, finitely many actual section generators are included in the actual quotient-kernel extension of their finite free image. The proved finite-type extension theorem replaces this by a global finite-type quasicoherent submodule with the same restriction. The actual finite join retains all of the prescribed generators. The selected opens need not cover the scheme.

Declarations

AlgebraicGeometry.Scheme.Modules.exists_finiteType_submodule_containing_sections_of_isCompact

A finite family on a compact open of a qcqs scheme belongs to a global finite-type quasicoherent native submodule.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
universe u v
open CategoryTheory Opposite TopologicalSpace
namespace AlgebraicGeometry.Scheme.Modules
theorem exists_finiteType_submodule_containing_sections_of_isCompact
    {X : Scheme.{u}} [CompactSpace X] [QuasiSeparatedSpace X]
    (F : SheafOfModules.{u} X.ringCatSheaf) [F.IsQuasicoherent]
    (U : X.Opens) (hU : IsCompact (U : Set X))
    {I : Type u} [Finite I] (s : I → F.val.obj (op U)) :
    ∃ N : F.Submodule, N.toSheafOfModules.IsQuasicoherent ∧
      N.toSheafOfModules.IsFiniteType ∧ ∀ i : I, s i ∈ N.toSubmodule.obj (op U)
AlgebraicGeometry.Scheme.Modules.exists_finiteType_submodule_containing_fg_sections

A finitely generated actual section submodule on a compact open is contained in a global finite-type quasicoherent native submodule.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
universe u v
open CategoryTheory Opposite TopologicalSpace
namespace AlgebraicGeometry.Scheme.Modules
theorem exists_finiteType_submodule_containing_fg_sections
    {X : Scheme.{u}} [CompactSpace X] [QuasiSeparatedSpace X]
    (F : SheafOfModules.{u} X.ringCatSheaf) [F.IsQuasicoherent]
    (U : X.Opens) (hU : IsCompact (U : Set X))
    (K : Submodule (X.ringCatSheaf.obj.obj (op U)) (F.val.obj (op U))) (hK : K.FG) :
    ∃ N : F.Submodule, N.toSheafOfModules.IsQuasicoherent ∧
      N.toSheafOfModules.IsFiniteType ∧ K ≤ N.toSubmodule.obj (op U)
AlgebraicGeometry.Scheme.Modules.exists_finiteType_submodule_containing_affine_sections

Finitely many finitely generated affine-local section submodules all belong to one actual finite-type quasicoherent native submodule.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
universe u v
open CategoryTheory Opposite TopologicalSpace
namespace AlgebraicGeometry.Scheme.Modules
theorem exists_finiteType_submodule_containing_affine_sections
    {X : Scheme.{u}} [CompactSpace X] [QuasiSeparatedSpace X]
    (F : SheafOfModules.{u} X.ringCatSheaf) [F.IsQuasicoherent]
    {I : Type v} [Finite I] (V : I → X.AffineZariskiSite)
    (K : ∀ i : I, Submodule (X.ringCatSheaf.obj.obj (op (V i).1))
      (F.val.obj (op (V i).1))) (hK : ∀ i : I, (K i).FG) :
    ∃ N : F.Submodule, N.toSheafOfModules.IsQuasicoherent ∧
      N.toSheafOfModules.IsFiniteType ∧
      ∀ i : I, K i ≤ N.toSubmodule.obj (op (V i).1)
AlgebraicGeometry.Scheme.Modules.exists_finite_quasicoherent_submodule_containing_affine_sections

On a qcqs scheme, finitely many specified finitely generated affine section submodules are contained in one actual quasicoherent submodule whose section module on every affine open is finitely generated.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
universe u v
open CategoryTheory Opposite TopologicalSpace
namespace AlgebraicGeometry.Scheme.Modules
theorem exists_finite_quasicoherent_submodule_containing_affine_sections
    {X : Scheme.{u}} [CompactSpace X] [QuasiSeparatedSpace X]
    (F : SheafOfModules.{u} X.ringCatSheaf) [F.IsQuasicoherent]
    {I : Type v} [Finite I] (V : I → X.AffineZariskiSite)
    (K : ∀ i : I, Submodule (X.ringCatSheaf.obj.obj (op (V i).1))
      (F.val.obj (op (V i).1))) (hK : ∀ i : I, (K i).FG) :
    ∃ N : F.Submodule, N.toSheafOfModules.IsQuasicoherent ∧
      (∀ W : X.AffineZariskiSite, (N.toSubmodule.obj (op W.1)).FG) ∧
      ∀ i : I, K i ≤ N.toSubmodule.obj (op (V i).1)