Module

GaloisAction.lean

Nyll.ClassFieldTheory.LubinTate.EqualCharacteristic.Ramification.GaloisAction
1 declaration indexed from sourceView source ↗

Galois action at an equal-characteristic Lubin--Tate level

This module identifies the action of every finite-level Galois automorphism on the chosen primitive division point with the corresponding truncated Lubin--Tate bracket.

Declarations

LubinTate.equalCharacteristicLubinTate_galoisAction_eq_bracket_unique

Equal-characteristic Lubin--Tate action frontier: every automorphism of the explicit level-n+1 field acts on the primitive generator through a unique visible unit-parameter bracket.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
universe u v
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTate_galoisAction_eq_bracket_unique
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ)
    (σ : Gal((equalCharacteristicLubinTateLevelField F n)/F.residueField⸨X⸩)) :
    ∃! a : equalCharacteristicLubinTateUnitParameter F n,
      σ (equalCharacteristicLubinTateLevelPowerBasis F n).gen =
        equalCharacteristicLubinTateLevelBracket F n (n + 1)
          (equalCharacteristicLubinTateUnitParameterSeries F n a)
          (equalCharacteristicLubinTateLevelPowerBasis F n).gen