Module

PullbackAlong.lean

Nyll.JacobianVarieties.Pic0.PullbackAlong
4 declarations indexed from sourceView source ↗

Pullback of degree-zero divisor classes

The pullback of divisors descends to the degree-zero Picard group.

Declarations

AlgebraicCurve.Pic0.pullbackAlongDegZeroHom

Pull back degree-zero divisors along the given embedding of function fields.

Source context 7 commands

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

noncomputable section
namespace AlgebraicCurve.Pic0
open Divisor
variable {K F F' : Type*} [Field K] [Field F] [Field F'] [Algebra K F] [Algebra K F']
variable [HasPrincipalDivisors K F']
variable (φ : F →ₐ[K] F') (hφ : φ.toRingHom.IsIntegral)
variable (hFI : FundamentalIdentityAlong K φ hφ)
def pullbackAlongDegZeroHom :
    Divisor.degZero (K := K) (F := F) →+ Divisor.degZero (K := K) (F := F')
AlgebraicCurve.Pic0.coe_pullbackAlongDegZeroHom
Source context 7 commands

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

noncomputable section
namespace AlgebraicCurve.Pic0
open Divisor
variable {K F F' : Type*} [Field K] [Field F] [Field F'] [Algebra K F] [Algebra K F']
variable [HasPrincipalDivisors K F']
variable (φ : F →ₐ[K] F') (hφ : φ.toRingHom.IsIntegral)
variable (hFI : FundamentalIdentityAlong K φ hφ)
theorem coe_pullbackAlongDegZeroHom (D : Divisor.degZero (K := K) (F := F)) :
    (pullbackAlongDegZeroHom φ hφ hFI D : Divisor K F') =
      Divisor.pullbackAlong φ hφ (D : Divisor K F)
AlgebraicCurve.Pic0.pullbackAlongHom

The induced pullback homomorphism on degree-zero divisor classes.

Source context 7 commands

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

noncomputable section
namespace AlgebraicCurve.Pic0
open Divisor
variable {K F F' : Type*} [Field K] [Field F] [Field F'] [Algebra K F] [Algebra K F']
variable [HasPrincipalDivisors K F']
variable (φ : F →ₐ[K] F') (hφ : φ.toRingHom.IsIntegral)
variable (hFI : FundamentalIdentityAlong K φ hφ)
def pullbackAlongHom : Pic0 K F →+ Pic0 K F'
AlgebraicCurve.Pic0.pullbackAlongHom_mk
Source context 7 commands

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

noncomputable section
namespace AlgebraicCurve.Pic0
open Divisor
variable {K F F' : Type*} [Field K] [Field F] [Field F'] [Algebra K F] [Algebra K F']
variable [HasPrincipalDivisors K F']
variable (φ : F →ₐ[K] F') (hφ : φ.toRingHom.IsIntegral)
variable (hFI : FundamentalIdentityAlong K φ hφ)
theorem pullbackAlongHom_mk (D : Divisor.degZero (K := K) (F := F)) :
    pullbackAlongHom φ hφ hFI (mk D) = mk (pullbackAlongDegZeroHom φ hφ hFI D)