Module

GluedUniversal.lean

Nyll.SchemeTheory.WeilRestriction.GluedUniversal
5 declarations indexed from sourceView source ↗

The universal section of glued local representers

The canonical transitions between local representers preserve their universal elements. These elements therefore form a compatible family on the locally directed cover of the glued scheme. The sheaf condition supplies a global section whose restriction to every local representer is its universal element.

Declarations

SchemeTheory.WeilRestriction.localRepresenterUniversalSection

The universal element of a local representer, viewed over the original base.

Source context 6 commands

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

@[expose] public section
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
noncomputable section
universe u v
namespace SchemeTheory.WeilRestriction
variable {S : Scheme.{u}} (F : (Over S)ᵒᵖ ⥤ Type u)
  (𝒰 : S.OpenCover) [Category.{v} 𝒰.I₀] [𝒰.LocallyDirected]
  (W : ∀ i : 𝒰.I₀, Over (𝒰.X i))
  (h : ∀ i : 𝒰.I₀, ((Over.map (𝒰.f i)).op ⋙ F).RepresentableBy (W i))
def localRepresenterUniversalSection (i : 𝒰.I₀) :
    F.obj (Opposite.op ((Over.map (𝒰.f i)).obj (W i)))
SchemeTheory.WeilRestriction.gluedLocalRepresenterHypercover

The Zariski hypercover of the glued representer given by its local representing schemes.

Source context 7 commands

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

@[expose] public section
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
noncomputable section
universe u v
namespace SchemeTheory.WeilRestriction
variable {S : Scheme.{u}} (F : (Over S)ᵒᵖ ⥤ Type u)
  (𝒰 : S.OpenCover) [Category.{v} 𝒰.I₀] [𝒰.LocallyDirected]
  (W : ∀ i : 𝒰.I₀, Over (𝒰.X i))
  (h : ∀ i : 𝒰.I₀, ((Over.map (𝒰.f i)).op ⋙ F).RepresentableBy (W i))
variable [Quiver.IsThin 𝒰.I₀] [Small.{u} 𝒰.I₀]
def gluedLocalRepresenterHypercover :
    (Scheme.zariskiTopology.over S).OneHypercover (gluedLocalRepresenter F 𝒰 W h)
SchemeTheory.WeilRestriction.gluedLocalRepresenterCompatibleSections

The compatible universal sections on the hypercover of the glued local representers.

Source context 7 commands

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

@[expose] public section
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
noncomputable section
universe u v
namespace SchemeTheory.WeilRestriction
variable {S : Scheme.{u}} (F : (Over S)ᵒᵖ ⥤ Type u)
  (𝒰 : S.OpenCover) [Category.{v} 𝒰.I₀] [𝒰.LocallyDirected]
  (W : ∀ i : 𝒰.I₀, Over (𝒰.X i))
  (h : ∀ i : 𝒰.I₀, ((Over.map (𝒰.f i)).op ⋙ F).RepresentableBy (W i))
variable [Quiver.IsThin 𝒰.I₀] [Small.{u} 𝒰.I₀]
def gluedLocalRepresenterCompatibleSections :
    ((gluedLocalRepresenterHypercover F 𝒰 W h).multicospanIndex F).sections
SchemeTheory.WeilRestriction.gluedLocalRepresenterUniversalSection

The local universal elements glue to a section on the glued representer.

Source context 8 commands

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

@[expose] public section
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
noncomputable section
universe u v
namespace SchemeTheory.WeilRestriction
variable {S : Scheme.{u}} (F : (Over S)ᵒᵖ ⥤ Type u)
  (𝒰 : S.OpenCover) [Category.{v} 𝒰.I₀] [𝒰.LocallyDirected]
  (W : ∀ i : 𝒰.I₀, Over (𝒰.X i))
  (h : ∀ i : 𝒰.I₀, ((Over.map (𝒰.f i)).op ⋙ F).RepresentableBy (W i))
variable [Quiver.IsThin 𝒰.I₀] [Small.{u} 𝒰.I₀]
variable (hF : Presheaf.IsSheaf (Scheme.zariskiTopology.over S) F)
def gluedLocalRepresenterUniversalSection :
    F.obj (Opposite.op (gluedLocalRepresenter F 𝒰 W h))
SchemeTheory.WeilRestriction.gluedLocalRepresenterUniversalSection_restrict

Restricting the glued section recovers the corresponding local universal element.

Source context 8 commands

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

@[expose] public section
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
noncomputable section
universe u v
namespace SchemeTheory.WeilRestriction
variable {S : Scheme.{u}} (F : (Over S)ᵒᵖ ⥤ Type u)
  (𝒰 : S.OpenCover) [Category.{v} 𝒰.I₀] [𝒰.LocallyDirected]
  (W : ∀ i : 𝒰.I₀, Over (𝒰.X i))
  (h : ∀ i : 𝒰.I₀, ((Over.map (𝒰.f i)).op ⋙ F).RepresentableBy (W i))
variable [Quiver.IsThin 𝒰.I₀] [Small.{u} 𝒰.I₀]
variable (hF : Presheaf.IsSheaf (Scheme.zariskiTopology.over S) F)
lemma gluedLocalRepresenterUniversalSection_restrict (i : 𝒰.I₀) :
    F.map (gluedLocalRepresenterInclusion F 𝒰 W h i).op
        (gluedLocalRepresenterUniversalSection F 𝒰 W h hF) =
      localRepresenterUniversalSection F 𝒰 W h i