Module

Cartier.lean

Nyll.AlgebraicCurves.RelativeDivisors.Cartier
8 declarations indexed from sourceView source ↗

Cartier conditions and morphisms of ideal sheaves

Defines local invertibility of ideals and compatibility of ideal morphisms with base change.

Imports2
Imported by120

Declarations

AlgebraicGeometry.Scheme.IdealSheafData.IsInvertible

The ideal is locally generated by a non-zero-divisor on affine basic opens.

Source context 4 commands

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

open CategoryTheory CategoryTheory.Limits TopologicalSpace Opposite
universe u
namespace AlgebraicGeometry.Scheme.IdealSheafData
variable {X : Scheme.{u}}
def IsInvertible (I : X.IdealSheafData) : Prop
AlgebraicGeometry.Scheme.IdealSheafData.isInvertible_top
Source context 4 commands

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

open CategoryTheory CategoryTheory.Limits TopologicalSpace Opposite
universe u
namespace AlgebraicGeometry.Scheme.IdealSheafData
variable {X : Scheme.{u}}
theorem isInvertible_top : (⊤ : X.IdealSheafData).IsInvertible
theorem

mul

L42 ↗
AlgebraicGeometry.Scheme.IdealSheafData.IsInvertible.mul
Source context 4 commands

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

open CategoryTheory CategoryTheory.Limits TopologicalSpace Opposite
universe u
namespace AlgebraicGeometry.Scheme.IdealSheafData
variable {X : Scheme.{u}}
theorem IsInvertible.mul {I J : X.IdealSheafData} (hI : I.IsInvertible) (hJ : J.IsInvertible) :
    (I * J).IsInvertible
AlgebraicGeometry.Scheme.IdealSheafData.IdealHom.appLE_mem_comap_ideal
Source context 6 commands

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

open CategoryTheory CategoryTheory.Limits TopologicalSpace Opposite
universe u
namespace AlgebraicGeometry.Scheme.IdealSheafData
variable {X : Scheme.{u}}
namespace IdealHom
variable {X' : Scheme.{u}} (f : X' ⟶ X) {I J : X.IdealSheafData}
theorem appLE_mem_comap_ideal (U : X.affineOpens) (U' : X'.affineOpens)
    (h : (U' : X'.Opens) ≤ f ⁻¹ᵁ U) (x : I.ideal U) :
    f.appLE U U' h x ∈ (I.comap f).ideal U'
AlgebraicGeometry.Scheme.IdealSheafData.IdealHom.IsBaseChangeAlong

The two ideal morphisms agree after restriction along the base change.

Source context 6 commands

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

open CategoryTheory CategoryTheory.Limits TopologicalSpace Opposite
universe u
namespace AlgebraicGeometry.Scheme.IdealSheafData
variable {X : Scheme.{u}}
namespace IdealHom
variable {X' : Scheme.{u}} (f : X' ⟶ X) {I J : X.IdealSheafData}
def IsBaseChangeAlong (φ : IdealHom I J) (φ' : IdealHom (I.comap f) (J.comap f)) : Prop
AlgebraicCurve.RelEffDivisor.IsCartier

The relative effective divisor has a locally invertible defining ideal.

Source context 5 commands

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

open CategoryTheory CategoryTheory.Limits TopologicalSpace Opposite
universe u
namespace AlgebraicCurve
open AlgebraicGeometry Scheme.IdealSheafData
variable {k : Type u} [Field k] {C : Scheme.{u}} {c : C ⟶ Spec (.of k)}
def RelEffDivisor.IsCartier {d : ℕ} {T : Scheme.{u}} {t : T ⟶ Spec (.of k)}
    (Z : RelEffDivisor C c d T t) : Prop
AlgebraicCurve.RelEffDivisor.const

The constant family obtained by pulling a divisor back from the field spectrum.

Source context 5 commands

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

open CategoryTheory CategoryTheory.Limits TopologicalSpace Opposite
universe u
namespace AlgebraicCurve
open AlgebraicGeometry Scheme.IdealSheafData
variable {k : Type u} [Field k] {C : Scheme.{u}} {c : C ⟶ Spec (.of k)}
def RelEffDivisor.const {r : ℕ}
    (D : RelEffDivisor C c r (Spec (.of k)) (𝟙 _)) {T : Scheme.{u}} (t : T ⟶ Spec (.of k)) :
    RelEffDivisor C c r T t
AlgebraicCurve.IdealHom.FibrewiseNonvanishing

The ideal morphism admits a compatible nonzero morphism on every fiber.

Source context 5 commands

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

open CategoryTheory CategoryTheory.Limits TopologicalSpace Opposite
universe u
namespace AlgebraicCurve
open AlgebraicGeometry Scheme.IdealSheafData
variable {k : Type u} [Field k] {C : Scheme.{u}} {c : C ⟶ Spec (.of k)}
def IdealHom.FibrewiseNonvanishing (c : C ⟶ Spec (.of k)) {T : Scheme.{u}}
    (t : T ⟶ Spec (.of k)) {I J : (pullback c t).IdealSheafData} (φ : IdealHom I J) : Prop