Module

Pic0_exists_jacobianPack_of_isAlgClosed.lean

Nyll.JacobianVarieties.Pic0.Pic0_exists_jacobianPack_of_isAlgClosed
1 declaration indexed from sourceView source ↗

A Jacobian scheme and its Picard-group parametrization over an algebraically closed field.

Declarations

AlgebraicCurve.Pic0.exists_jacobianPack_of_isAlgClosed

The curve has a smooth proper connected Jacobian with the specified addition law.

Source context 4 commands

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

section ProofImplementation
namespace AlgebraicCurve.Pic0
open _root_.JacobianVarieties.Pic0.Proofs.Pic0_exists_jacobianPack_of_isAlgClosed
open _root_.CategoryTheory _root_.CategoryTheory.Limits _root_.AlgebraicGeometry
  _root_.AlgebraicCurve _root_.NeronModelInfra
  _root_.GoodReductionJacobian _root_.AlgebraicGeometry.RelPicard
theorem exists_jacobianPack_of_isAlgClosed
    (K F : Type*) [Field K] [Field F] [Algebra K F]
    [IsAlgClosed K]
    (hfg : ∃ x : F, Transcendental K x ∧
      FiniteDimensional (IntermediateField.adjoin K ({x} : Set F)) F)
    [IsCurveOver K F] :
    ∃ (J : AlgebraicGeometry.Scheme) (c : J ⟶ AlgebraicGeometry.Spec (CommRingCat.of K)),
      AlgebraicGeometry.Smooth c ∧ AlgebraicGeometry.IsProper c ∧ ConnectedSpace J ∧
      ∃ (mul : CategoryTheory.Limits.pullback c c ⟶ J)
        (pts : Pic0 K F ≃
          {σ : AlgebraicGeometry.Spec (CommRingCat.of K) ⟶ J // σ ≫ c = 𝟙 _}),
        ∀ x y : Pic0 K F, (pts (x + y)).1 =
          CategoryTheory.Limits.pullback.lift (pts x).1 (pts y).1
            ((pts x).2.trans (pts y).2.symm) ≫ mul