Module

MixedCharPrincipalUnitEigenLift.lean

Nyll.Yamaguchi26AbfaithfulGalois.Analytic.MixedCharPrincipalUnitEigenLift
1 declaration indexed from sourceView source ↗

Character eigenvectors in the logarithm image lift to principal units

The actual logarithm intertwines the constructed p-adic representations. The group order is a unit because it is prime to the residue characteristic, so character averaging produces an eigenvector preimage.

Declarations

LocalFieldTheory.DiscreteValuationField.MultiplicativeIntegerValuation.exists_principalUnit_log_eigen_lift

Every character eigenvector in the actual log image lifts to a character eigenvector in the actual principal-unit group.

Source context 5 commands

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

namespace LocalFieldTheory.DiscreteValuationField.MultiplicativeIntegerValuation
universe u w
variable {K : Type u} [Field K] [CharZero K]
variable {Δ : Type w} [Group Δ] [Fintype Δ]
open CompleteDVF.higherPrincipalUnitGroup
theorem exists_principalUnit_log_eigen_lift
    (v : _root_.Valuation K (WithZero (Multiplicative ℤ)))
    [ValuationTheory.DiscreteValuationField.Valuation.IsCompleteDiscrete v]
    (p : ℕ) [Fact p.Prime] [CharP (IsLocalRing.ResidueField v.valuationSubring) p]
    (σ : Δ →* (K ≃+* K)) (hval : ∀ (g : Δ) (x : K), v (σ g x) = v x)
    (hcard : p.Coprime (Fintype.card Δ)) (χ : Δ →* ℤ_[p]ˣ) (b : K)
    (himage : ∃ x : CompleteDVF.higherPrincipalUnitGroup (completeDVFOfWithZeroValuation v) 1,
      (principalUnitLogOfMixedChar v p x).toAdd = b)
    (heigen : ∀ g : Δ, σ g b = padicIntToFieldOfMixedChar v p (χ g : ℤ_[p]) * b) :
    ∃ x : CompleteDVF.higherPrincipalUnitGroup (completeDVFOfWithZeroValuation v) 1,
      (principalUnitLogOfMixedChar v p x).toAdd = b ∧
      ∀ g : Δ,
        σ g (((x : (completeDVFOfWithZeroValuation v).valuationSubringˣ) :
          (completeDVFOfWithZeroValuation v).valuationSubring) : K) =
        (((principalUnitPadicPowOfMixedChar v p (χ g : ℤ_[p]) x :
          (completeDVFOfWithZeroValuation v).valuationSubringˣ) :
          (completeDVFOfWithZeroValuation v).valuationSubring) : K)