Module

OpenBoundaryRealization.lean

Nyll.JacobianVarieties.Kummer.OpenBoundaryRealization
1 declaration indexed from sourceView source ↗

Realizing degree-zero boundary residues

A residue vector of sum zero lifts to a degree-zero integral divisor supported on the boundary: subtract its total integral degree at a chosen boundary point. Actual Pic⁰ divisibility then realizes that divisor modulo the exponent by a function unramified away from the boundary.

Declarations

AlgebraicCurve.CurveModel.exists_openKummerUnits_of_sum_eq_zero

Every sum-zero boundary residue vector is realized by an actual function whose orders off the boundary are divisible by the exponent.

Source context 4 commands

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

noncomputable section
open CategoryTheory AlgebraicGeometry NeronModelInfra
open scoped BigOperators
namespace AlgebraicCurve.CurveModel
theorem exists_openKummerUnits_of_sum_eq_zero
    {K F : Type} [Field K] [IsAlgClosed K]
    [Field F] [Algebra K F] [IsCurveOver K F]
    (M : CurveModel K F)
    (ε : SchemeHomOver (𝟙 (Spec (.of K))) M.toBase)
    (S : Set (Place K F)) [Fintype S]
    (v₀ : S) (n : ℕ+) (hchar : ((n : ℕ) : K) ≠ 0)
    (a : S → ZMod (n : ℕ)) (ha : ∑ v : S, a v = 0) :
    ∃ u : Pic0.openKummerUnits K F S n,
      Pic0.openKummerResidue S n u = Multiplicative.ofAdd a