Module

UnpointedPointedComparison.lean

Nyll.JacobianVarieties.Picard.UnpointedPointedComparison
7 declarations indexed from sourceView source ↗

Comparison of the unpointed Jacobian with a pointed Picard representative

When an actual rational point and a pointed representation are provided, the same chosen unpointed Jacobian represents the unrigidified presheaf. Descending the local universal element fixes its comparison with the pointed representative.

Declarations

JacobianVarieties.Picard.Unpointed.pointedUnrigidifiedRepresentation

The pointed Picard representative also represents the actual unrigidified classes.

Source context 6 commands

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

universe u
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry AlgebraicGeometry.RelPicard
open AlgebraicGeometry.SmoothProperCurve NeronModelInfra GoodReductionJacobian Opposite
noncomputable section
namespace JacobianVarieties.Picard.Unpointed
variable {K : Type u} [Field K] {C : Scheme.{u}} {c : C ⟶ Spec (CommRingCat.of K)}
  (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of K))) c)
  {D : RelativePic0Designation K c}
  (h : RepresentsRelSubPic c ε (algEquivZeroCut c ε) D)
def pointedUnrigidifiedRepresentation :
    (Unrigidified.zeroPresheaf c).RepresentableBy (Over.mk D.toBase)
JacobianVarieties.Picard.Unpointed.Presentation.pointedRepresentation

A pointed curve makes its actual quotient presheaf a sheaf on the finite faithfully flat cover, so the descended universal element represents it globally.

Source context 6 commands

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

universe u
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry AlgebraicGeometry.RelPicard
open AlgebraicGeometry.SmoothProperCurve NeronModelInfra GoodReductionJacobian Opposite
noncomputable section
namespace JacobianVarieties.Picard.Unpointed
variable {K : Type u} [Field K] {C : Scheme.{u}} {c : C ⟶ Spec (CommRingCat.of K)}
  (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of K))) c)
  {D : RelativePic0Designation K c}
  (h : RepresentsRelSubPic c ε (algEquivZeroCut c ε) D)
def Presentation.pointedRepresentation (M : Presentation K c) :
    (Unrigidified.zeroPresheaf c).RepresentableBy (Over.mk M.toBase)
JacobianVarieties.Picard.Unpointed.Presentation.pointedComparisonOver

The over-scheme isomorphism fixed by the actual two Picard classifications.

Source context 6 commands

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

universe u
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry AlgebraicGeometry.RelPicard
open AlgebraicGeometry.SmoothProperCurve NeronModelInfra GoodReductionJacobian Opposite
noncomputable section
namespace JacobianVarieties.Picard.Unpointed
variable {K : Type u} [Field K] {C : Scheme.{u}} {c : C ⟶ Spec (CommRingCat.of K)}
  (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of K))) c)
  {D : RelativePic0Designation K c}
  (h : RepresentsRelSubPic c ε (algEquivZeroCut c ε) D)
def Presentation.pointedComparisonOver (M : Presentation K c) :
    Over.mk M.toBase ≅ Over.mk D.toBase
JacobianVarieties.Picard.Unpointed.Presentation.pointedComparison

The actual scheme comparison with any pointed Picard representative.

Source context 6 commands

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

universe u
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry AlgebraicGeometry.RelPicard
open AlgebraicGeometry.SmoothProperCurve NeronModelInfra GoodReductionJacobian Opposite
noncomputable section
namespace JacobianVarieties.Picard.Unpointed
variable {K : Type u} [Field K] {C : Scheme.{u}} {c : C ⟶ Spec (CommRingCat.of K)}
  (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of K))) c)
  {D : RelativePic0Designation K c}
  (h : RepresentsRelSubPic c ε (algEquivZeroCut c ε) D)
def Presentation.pointedComparison (M : Presentation K c) : M.carrier ≅ D.P
JacobianVarieties.Picard.Unpointed.Presentation.pointedComparison_over
Source context 6 commands

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

universe u
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry AlgebraicGeometry.RelPicard
open AlgebraicGeometry.SmoothProperCurve NeronModelInfra GoodReductionJacobian Opposite
noncomputable section
namespace JacobianVarieties.Picard.Unpointed
variable {K : Type u} [Field K] {C : Scheme.{u}} {c : C ⟶ Spec (CommRingCat.of K)}
  (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of K))) c)
  {D : RelativePic0Designation K c}
  (h : RepresentsRelSubPic c ε (algEquivZeroCut c ε) D)
theorem Presentation.pointedComparison_over (M : Presentation K c) :
    (M.pointedComparison ε h).hom ≫ D.toBase = M.toBase
JacobianVarieties.Picard.Unpointed.pointedComparison

An actual section identifies the fixed unpointed Jacobian with a pointed Picard representative over the original field.

Source context 7 commands

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

universe u
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry AlgebraicGeometry.RelPicard
open AlgebraicGeometry.SmoothProperCurve NeronModelInfra GoodReductionJacobian Opposite
noncomputable section
namespace JacobianVarieties.Picard.Unpointed
variable {K : Type u} [Field K] {C : Scheme.{u}} {c : C ⟶ Spec (CommRingCat.of K)}
  (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of K))) c)
  {D : RelativePic0Designation K c}
  (h : RepresentsRelSubPic c ε (algEquivZeroCut c ε) D)
variable (c) [IsProper c] [SmoothOfRelativeDimension 1 c] [GeometricallyIrreducible c]
def pointedComparison : Jacobian K c ≅ D.P
JacobianVarieties.Picard.Unpointed.pointedComparison_over
Source context 7 commands

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

universe u
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry AlgebraicGeometry.RelPicard
open AlgebraicGeometry.SmoothProperCurve NeronModelInfra GoodReductionJacobian Opposite
noncomputable section
namespace JacobianVarieties.Picard.Unpointed
variable {K : Type u} [Field K] {C : Scheme.{u}} {c : C ⟶ Spec (CommRingCat.of K)}
  (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of K))) c)
  {D : RelativePic0Designation K c}
  (h : RepresentsRelSubPic c ε (algEquivZeroCut c ε) D)
variable (c) [IsProper c] [SmoothOfRelativeDimension 1 c] [GeometricallyIrreducible c]
theorem pointedComparison_over :
    (pointedComparison c ε h).hom ≫ D.toBase = toBase K c