Module

Action.lean

Nyll.ClassFieldTheory.AlgebraicNumberTheory.Idele.Cohomology.SPlaces.OutsideIntegralInduced.LocalInduction.Action
1 declaration indexed from sourceView source ↗

Integral local induced modules

This file identifies the product of valuation-ring unit groups over the extensions of a finite place with the corresponding induced module.

Declarations

The decomposition-group action on the units of the intrinsic integer ring of the chosen localization.

Source context 10 commands

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

open scoped NumberField TensorProduct ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable
    {K : Type} {L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
section IntegralInduction
variable (vK : AbsoluteValue K ℝ) (hvK : vK.IsNontrivial)
    (hvKna : IsNonarchimedean (vK : K → ℝ))
    (w : AbsoluteValueExtension vK L)
def decompositionGroupLocalizedIntegerUnitsAction :
    letI := LocalInductionInternal.extensionCompletionAlgebra vK w
    letI : SMul K w.1.Completion :=
      LocalInductionInternal.extensionCompletionSMul vK w
    letI := LocalInductionInternal.completionAlgebra vK w
    letI : Valued vK.Completion ℝ≥0 :=
      LocalInductionInternal.baseValued vK hvKna
    letI : ValuativeRel vK.Completion :=
      LocalInductionInternal.baseValuativeRel vK hvKna
    letI : Valued (LocalizedCompletion vK w) ℝ≥0 :=
      LocalInductionInternal.localizedValued vK w hvKna
    letI : ValuativeRel (LocalizedCompletion vK w) :=
      LocalInductionInternal.localizedValuativeRel vK w hvKna
    letI : Algebra 𝒪[vK.Completion] (LocalizedCompletion vK w) :=
      LocalInductionInternal.integerAlgebra vK w hvKna
    letI := LocalInductionInternal.valuationHasExtension vK w hvKna
    letI := LocalInductionInternal.isIntegralClosure
      vK w hvK hvKna
    MulDistribMulAction
      (absoluteValueDecompositionGroup K w.1)
      𝒪[LocalizedCompletion vK w]ˣ := by
  letI := LocalInductionInternal.extensionCompletionAlgebra vK w
  letI : SMul K w.1.Completion :=
    LocalInductionInternal.extensionCompletionSMul vK w
  letI := LocalInductionInternal.completionAlgebra vK w
  letI : Valued vK.Completion ℝ≥0 :=
    LocalInductionInternal.baseValued vK hvKna
  letI : ValuativeRel vK.Completion :=
    LocalInductionInternal.baseValuativeRel vK hvKna
  letI : Valued (LocalizedCompletion vK w) ℝ≥0 :=
    LocalInductionInternal.localizedValued vK w hvKna
  letI : ValuativeRel (LocalizedCompletion vK w) :=
    LocalInductionInternal.localizedValuativeRel vK w hvKna
  letI : Algebra 𝒪[vK.Completion] (LocalizedCompletion vK w) :=
    LocalInductionInternal.integerAlgebra vK w hvKna
  letI := LocalInductionInternal.valuationHasExtension vK w hvKna
  letI := LocalInductionInternal.isIntegralClosure
    vK w hvK hvKna
  letI : MulDistribMulAction
      (Gal(LocalizedCompletion vK w / vK.Completion))
      𝒪[LocalizedCompletion vK w]ˣ :=
    galoisGroupIntegerUnitsMulDistribMulActionOfIsIntegralClosure
      vK.Completion (LocalizedCompletion vK w)
  exact
    MulDistribMulAction.compHom
      𝒪[LocalizedCompletion vK w]ˣ
      (decompositionGroupEquivAlgebraicLocalizationAut
        vK hvK w).toMonoidHom