Module

RelEffCartierDiv_isInvertible_I_ofPoint_of_range_subset.lean

Nyll.JacobianVarieties.Picard.RelEffCartierDiv_isInvertible_I_ofPoint_of_range_subset
6 declarations indexed from sourceView source ↗

Invertibility of the ideal of a point on the smooth locus

The point ideal is invertible after restriction to the smooth open and is the unit ideal on the complement of the graph. These two descriptions give an invertible ideal globally.

Declarations

JacobianVarieties.Picard.Proofs.PointIdealInvertibility.SectInvAux.jV

The open immersion on the pullbacks induced by an open of the curve.

Source context 5 commands

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

section ProofImplementation
namespace JacobianVarieties.Picard.Proofs.PointIdealInvertibility
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
universe u
namespace SectInvAux
def jV {R : Type u} [CommRing R] {C : Scheme.{u}}
    (c : C ⟶ Spec (CommRingCat.of R)) (V : C.Opens)
    {T : Scheme.{u}} (t : T ⟶ Spec (CommRingCat.of R)) : pullback (V.ι ≫ c) t ⟶ pullback c t
Source context 5 commands

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

section ProofImplementation
namespace JacobianVarieties.Picard.Proofs.PointIdealInvertibility
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
universe u
namespace SectInvAux
instance {R : Type u} [CommRing R] {C : Scheme.{u}}
    (c : C ⟶ Spec (CommRingCat.of R)) (V : C.Opens)
    {T : Scheme.{u}} (t : T ⟶ Spec (CommRingCat.of R)) : IsOpenImmersion (jV c V t)
JacobianVarieties.Picard.Proofs.PointIdealInvertibility.SectInvAux.jV_fst
Source context 5 commands

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

section ProofImplementation
namespace JacobianVarieties.Picard.Proofs.PointIdealInvertibility
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
universe u
namespace SectInvAux
lemma jV_fst {R : Type u} [CommRing R] {C : Scheme.{u}}
    (c : C ⟶ Spec (CommRingCat.of R)) (V : C.Opens)
    {T : Scheme.{u}} (t : T ⟶ Spec (CommRingCat.of R)) :
    jV c V t ≫ pullback.fst c t = pullback.fst _ _ ≫ V.ι
JacobianVarieties.Picard.Proofs.PointIdealInvertibility.SectInvAux.jV_snd
Source context 5 commands

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

section ProofImplementation
namespace JacobianVarieties.Picard.Proofs.PointIdealInvertibility
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
universe u
namespace SectInvAux
lemma jV_snd {R : Type u} [CommRing R] {C : Scheme.{u}}
    (c : C ⟶ Spec (CommRingCat.of R)) (V : C.Opens)
    {T : Scheme.{u}} (t : T ⟶ Spec (CommRingCat.of R)) :
    jV c V t ≫ pullback.snd c t = pullback.snd _ _ ≫ 𝟙 T
JacobianVarieties.Picard.Proofs.PointIdealInvertibility.SectInvAux.isPullback_of_fac
Source context 5 commands

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

section ProofImplementation
namespace JacobianVarieties.Picard.Proofs.PointIdealInvertibility
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
universe u
namespace SectInvAux
lemma isPullback_of_fac {P X Y : Scheme.{u}} (γ' : P ⟶ Y) (j : Y ⟶ X) [Mono j]
    (γ : P ⟶ X) (h : γ' ≫ j = γ) :
    IsPullback γ' (𝟙 P) j γ
AlgebraicGeometry.RelEffCartierDiv.isInvertible_I_ofPoint_of_range_subset
Source context 6 commands

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

section ProofImplementation
namespace JacobianVarieties.Picard.Proofs.PointIdealInvertibility
open CategoryTheory CategoryTheory.Limits AlgebraicGeometry
universe u
open scoped _root_.JacobianVarieties.Picard.Proofs.PointIdealInvertibility.SectInvAux
open SectInvAux in
theorem _root_.AlgebraicGeometry.RelEffCartierDiv.isInvertible_I_ofPoint_of_range_subset
    {R : Type u} [CommRing R] {C : Scheme.{u}} (c : C ⟶ Spec (CommRingCat.of R)) [IsSeparated c]
    (V : C.Opens) [SmoothOfRelativeDimension 1 (V.ι ≫ c)]
    {T : Scheme.{u}} (t : T ⟶ Spec (CommRingCat.of R)) (a : T ⟶ C) (ha : a ≫ c = t)
    (hV : Set.range a.base ⊆ (V : Set C)) :
    (RelEffCartierDiv.ofPoint c a ha).I.IsInvertible