Module

IsFinite_toBase_of_geometricFibre_genus_eq_zero.lean

Nyll.JacobianVarieties.Picard.IsFinite_toBase_of_geometricFibre_genus_eq_zero
1 declaration indexed from sourceView source ↗

Prove finiteness of a relative Picard scheme when every geometric fibre has genus zero.

Declarations

AlgebraicGeometry.RelPicard.isFinite_toBase_of_geometricFibre_genus_eq_zero
Source context 11 commands

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

section ProofImplementation
namespace AlgebraicGeometry.RelPicard
open _root_.JacobianVarieties.Picard.Proofs.GenusZeroFinite
universe u
open _root_.CategoryTheory
open _root_.CategoryTheory.Limits
open _root_.AlgebraicGeometry
open _root_.AlgebraicGeometry.RelPicard
open _root_.NeronModelInfra
open _root_.GoodReductionJacobian
open _root_.AlgebraicCurve hiding genus
theorem isFinite_toBase_of_geometricFibre_genus_eq_zero
    (k : Type u) [Field k] {C : Scheme.{u}} (c : C ⟶ Spec (CommRingCat.of k))
    [IsProper c] [SmoothOfRelativeDimension 1 c] [GeometricallyIntegral c]
    (ε : SchemeHomOver (𝟙 (Spec (CommRingCat.of k))) c)
    (J : RelativePic0Designation k c) (h : RepresentsRelSubPic c ε (algEquivZeroCut c ε) J)
    (hpr : IsProper J.toBase)
    (hg : ∀ (k' : Type u) [Field k'] [IsAlgClosed k'] (s : Spec (CommRingCat.of k') ⟶ Spec
      (CommRingCat.of k))
      (L : Type u) [Field L] [Algebra k' L] (M : CurveModel k' L) (e : M.C ≅ pullback c s)
      (_ : e.hom ≫ pullback.snd c s = M.toBase) (Kc : Divisor k' L) (g' : ℕ),
      (∀ D : Divisor k' L, (ell D : ℤ) - ell (Kc - D) = Divisor.degree D + 1 - g') → g' = 0) :
    IsFinite J.toBase