Finiteness of the toric H^1 quotient for a plane cover
OpenOAI.MaximalSeshadri.Projective.finite_plane_H1Let be a field, , and sections of a module with iso-opens covering such that sectionsMorphism k s hs to the plane is finite. For a line bundle , the quotient of cycles by vertexBoundaries of the edge submodules planePair and vertex submodules planeVertex inside the sections over the triple overlap is finite-dimensional over .
Notation. The iso-open of (SectionOpens.isoOpen s) is the union of the opens on which the morphism restricts to an isomorphism. sectionsMorphism k s hs is the morphism from to of the graded polynomial ring in variables indexed by the sections, defined by sections whose iso-opens cover , with the ring map from the base into . cycles A B C is the submodule of of triples with zero sum. planeVertex and planePair are the images in the sections over the triple overlap (planeTriple) of sections over the chart of , and over the overlap of the charts of , respectively.
Formalization Note The statement is verbatim from OpenAI's Lean development, with Definitions files of this development imported in place of the upstream modules; these are supporting code for the statement.
import Mathlib
import Definitions.Def_MaximalSeshadriConstants
import Definitions.Def_SeshadriPrelim6
namespace OAI
section
namespace MaximalSeshadri.Projective
noncomputable section
open AlgebraicGeometry CategoryTheory TopologicalSpace
open MaximalSeshadri.Geometry MaximalSeshadri.Geometry.BaseSections MaximalSeshadri.Frames
open MaximalSeshadri.LaurentPlane MaximalSeshadri.PlaneCech
variable {K : Type} [Field K] {X : Scheme.{0}} {M : X.Modules}
theorem finite_plane_H1 (k : K →+* Γ(X,⊤))
(s : Fin 3 → (O X ⟶ M)) (hs : (⨆ i, SectionOpens.isoOpen (s i)) = ⊤)
[IsFinite (sectionsMorphism k s hs)] (L : LineBundle X) :
Module.Finite K ((cycles (planePair k s L 0 1) (planePair k s L 0 2) (planePair k s L 1 2)) ⧸
vertexBoundaries (planePair k s L 0 1) (planePair k s L 0 2) (planePair k s L 1 2)
(planeVertex k s L)) := by
sorry
end
end MaximalSeshadri.Projective
end
end OAI