Module

Representation.lean

Nyll.JacobianVarieties.Picard.Representation
5 declarations indexed from sourceView source ↗

Universal families for relative sub-Picard conditions

A Poincaré family on a designated scheme classifies the line bundles satisfying a sub-Picard condition through unique maps over the base. Its restriction to the chosen zero section is trivial. The chosen classifying map is characterized by this universal property.

Imports3
Imported by177

Declarations

AlgebraicGeometry.RelPicard.RepresentsRelSubPic

A Poincaré family with a unique classifying map and a trivial zero-section restriction.

Source context 4 commands

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

namespace AlgebraicGeometry.RelPicard
open CategoryTheory CategoryTheory.Limits NeronModelInfra GoodReductionJacobian
universe u
variable {R : Type u} [CommRing R] {C : Scheme.{u}}
structure RepresentsRelSubPic (c : C ⟶ Spec (CommRingCat.of R))
    (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of R))) c)
    (P : SubPicCondition c ε) (D : RelativePic0Designation R c) : Type (u + 1) where

  /-- The rigidified Poincaré family on the designated carrier. -/
  poincare : RigidifiedLineBundle c ε D.toBase
  /-- The Poincaré family satisfies the sub-Picard condition. -/
  poincare_mem : P.P D.toBase poincare

  /-- Every family satisfying the condition has a unique classifying map over the base. -/
  univ : ∀ {T : Scheme.{u}} (t : T ⟶ Spec (CommRingCat.of R))
    (M : RigidifiedLineBundle c ε t), P.P t M →
    ∃! g : SchemeHomOver t D.toBase, Nonempty ((poincare.pullbackAlong g).L ≅ M.L)

  /-- The underlying line bundle pulled back to the zero section is the unit bundle. -/
  zero : Nonempty ((poincare.pullbackAlong ⟨D.zeroSection, D.zeroSection_toBase⟩).L ≅
    (RigidifiedLineBundle.unit (c := c) (ε := ε) (𝟙 _)).L)
AlgebraicGeometry.RelPicard.RepresentsRelSubPic.classify

Choose the unique map classifying a family satisfying the sub-Picard condition.

Source context 6 commands

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

namespace AlgebraicGeometry.RelPicard
open CategoryTheory CategoryTheory.Limits NeronModelInfra GoodReductionJacobian
universe u
variable {R : Type u} [CommRing R] {C : Scheme.{u}}
namespace RepresentsRelSubPic
variable {c : C ⟶ Spec (CommRingCat.of R)} {ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of R))) c}
  {P : SubPicCondition c ε} {D : RelativePic0Designation R c}
def classify (h : RepresentsRelSubPic c ε P D) {T : Scheme.{u}}
    (t : T ⟶ Spec (CommRingCat.of R))
    (M : RigidifiedLineBundle c ε t) (hM : P.P t M) : SchemeHomOver t D.toBase
AlgebraicGeometry.RelPicard.RepresentsRelSubPic.classify_spec
Source context 6 commands

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

namespace AlgebraicGeometry.RelPicard
open CategoryTheory CategoryTheory.Limits NeronModelInfra GoodReductionJacobian
universe u
variable {R : Type u} [CommRing R] {C : Scheme.{u}}
namespace RepresentsRelSubPic
variable {c : C ⟶ Spec (CommRingCat.of R)} {ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of R))) c}
  {P : SubPicCondition c ε} {D : RelativePic0Designation R c}
theorem classify_spec (h : RepresentsRelSubPic c ε P D) {T : Scheme.{u}}
    (t : T ⟶ Spec (CommRingCat.of R))
    (M : RigidifiedLineBundle c ε t) (hM : P.P t M) :
    Nonempty ((h.poincare.pullbackAlong (h.classify t M hM)).L ≅ M.L)
AlgebraicGeometry.RelPicard.RepresentsRelSubPic.classify_unique
Source context 6 commands

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

namespace AlgebraicGeometry.RelPicard
open CategoryTheory CategoryTheory.Limits NeronModelInfra GoodReductionJacobian
universe u
variable {R : Type u} [CommRing R] {C : Scheme.{u}}
namespace RepresentsRelSubPic
variable {c : C ⟶ Spec (CommRingCat.of R)} {ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of R))) c}
  {P : SubPicCondition c ε} {D : RelativePic0Designation R c}
theorem classify_unique (h : RepresentsRelSubPic c ε P D) {T : Scheme.{u}}
    (t : T ⟶ Spec (CommRingCat.of R))
    (M : RigidifiedLineBundle c ε t) (hM : P.P t M) (g : SchemeHomOver t D.toBase)
    (hg : Nonempty ((h.poincare.pullbackAlong g).L ≅ M.L)) : g = h.classify t M hM
AlgebraicGeometry.RelPicard.RepresentsRelSubPic.ext_of_iso
Source context 6 commands

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

namespace AlgebraicGeometry.RelPicard
open CategoryTheory CategoryTheory.Limits NeronModelInfra GoodReductionJacobian
universe u
variable {R : Type u} [CommRing R] {C : Scheme.{u}}
namespace RepresentsRelSubPic
variable {c : C ⟶ Spec (CommRingCat.of R)} {ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of R))) c}
  {P : SubPicCondition c ε} {D : RelativePic0Designation R c}
theorem ext_of_iso (h : RepresentsRelSubPic c ε P D) {T : Scheme.{u}}
    (t : T ⟶ Spec (CommRingCat.of R))
    (g g' : SchemeHomOver t D.toBase)
    (hgg' : Nonempty ((h.poincare.pullbackAlong g).L ≅
      (h.poincare.pullbackAlong g').L)) : g = g'