Module

FinitePlaceH2Localization.lean

Nyll.SawinTotallyRealTowers.UnramifiedProPRelationRank.Local.FinitePlaceH2Localization
6 declarations indexed from sourceView source ↗

Degree-two localization at a finite place

For a number field and a finite place, the chosen extension of the adic absolute value to the algebraic closure defines an absolute decomposition subgroup. Its continuous inclusion in the absolute Galois group induces the actual restriction map on degree-two continuous cohomology.

This file deliberately stops at the decomposition-group target. Identifying that target with the absolute Galois group of the completed field requires a topological local--global Galois comparison which is not presently available in the imported libraries.

Declarations

ClassFieldTower.Martinet.Shafarevich.finitePlaceAbsoluteValueExtension

The chosen extension of the finite-place absolute value to the algebraic closure.

Source context 8 commands

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

open CategoryTheory NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations
open ClassFieldTower.Cohomology
variable (F : Type) [Field F] [NumberField F]
variable (p : ℕ)
def finitePlaceAbsoluteValueExtension
    (v : HeightOneSpectrum (NumberField.RingOfIntegers F)) :
    AbsoluteValueExtension
      (NumberField.HeightOneSpectrum.adicAbv F v) (AlgebraicClosure F)
ClassFieldTower.Martinet.Shafarevich.finitePlaceAbsoluteDecompositionGroup

The decomposition subgroup of the absolute Galois group selected by a finite place.

Source context 8 commands

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

open CategoryTheory NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations
open ClassFieldTower.Cohomology
variable (F : Type) [Field F] [NumberField F]
variable (p : ℕ)
abbrev finitePlaceAbsoluteDecompositionGroup
    (v : HeightOneSpectrum (NumberField.RingOfIntegers F))
ClassFieldTower.Martinet.Shafarevich.finitePlaceAbsoluteDecompositionInclusion

The continuous inclusion of the selected decomposition subgroup in the absolute Galois group.

Source context 8 commands

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

open CategoryTheory NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations
open ClassFieldTower.Cohomology
variable (F : Type) [Field F] [NumberField F]
variable (p : ℕ)
def finitePlaceAbsoluteDecompositionInclusion
    (v : HeightOneSpectrum (NumberField.RingOfIntegers F)) :
    finitePlaceAbsoluteDecompositionGroup F v →ₜ* Field.absoluteGaloisGroup F
ClassFieldTower.Martinet.Shafarevich.finitePlaceAbsoluteDecompositionInclusion_apply
Source context 8 commands

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

open CategoryTheory NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations
open ClassFieldTower.Cohomology
variable (F : Type) [Field F] [NumberField F]
variable (p : ℕ)
theorem finitePlaceAbsoluteDecompositionInclusion_apply
    (v : HeightOneSpectrum (NumberField.RingOfIntegers F))
    (sigma : finitePlaceAbsoluteDecompositionGroup F v) :
    finitePlaceAbsoluteDecompositionInclusion F v sigma = sigma.1
ClassFieldTower.Martinet.Shafarevich.finitePlaceH2Localization

Restriction of degree-two continuous cohomology from the absolute Galois group to the decomposition subgroup at v.

Source context 8 commands

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

open CategoryTheory NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations
open ClassFieldTower.Cohomology
variable (F : Type) [Field F] [NumberField F]
variable (p : ℕ)
def finitePlaceH2Localization
    (v : HeightOneSpectrum (NumberField.RingOfIntegers F)) :
    continuousCohomologyZModPLifted p (Field.absoluteGaloisGroup F) 2 →ₗ[ZMod p]
      continuousCohomologyZModPLifted p
        (finitePlaceAbsoluteDecompositionGroup F v) 2
ClassFieldTower.Martinet.Shafarevich.finitePlaceH2Localization_quotientMap

Localization sends a cocycle class to the class of its restriction to the decomposition subgroup.

Source context 8 commands

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

open CategoryTheory NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations
open ClassFieldTower.Cohomology
variable (F : Type) [Field F] [NumberField F]
variable (p : ℕ)
theorem finitePlaceH2Localization_quotientMap
    (v : HeightOneSpectrum (NumberField.RingOfIntegers F))
    (z : trivialZModPCocyclesLifted p (Field.absoluteGaloisGroup F) 2) :
    finitePlaceH2Localization F p v
        (ContinuousCohomology.π (trivialZModPLifted p (Field.absoluteGaloisGroup F)) 2 z) =
      ContinuousCohomology.π
        (trivialZModPLifted p (finitePlaceAbsoluteDecompositionGroup F v)) 2
        (trivialZModPCocyclesMapLifted p
          (finitePlaceAbsoluteDecompositionInclusion F v) 2 z)