Module

HerbrandFunctionInverseHerbrandFunction.lean

Nyll.ClassFieldTheory.Theorems.HasseArf.HerbrandFunctionInverseHerbrandFunction
1 declaration indexed from sourceView source ↗

The Herbrand function is a right inverse

Declarations

ClassFieldTheory.herbrandFunction_inverseHerbrandFunction

The public Herbrand function takes its inverse value back to the given upper index.

Source context 5 commands

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

noncomputable section
namespace ClassFieldTheory
open LocalFieldTheory
open RamificationTheory.LocalField
open RamificationTheory.HilbertRamification.Higher
theorem herbrandFunction_inverseHerbrandFunction
    (K L : Type) [Field K] [Field L] [Algebra K L]
    [FiniteDimensional K L] [IsAbelianGalois K L]
    [ValuativeRel K] [TopologicalSpace K]
    [IsNonarchimedeanLocalField K]
    [ValuativeRel L] [TopologicalSpace L]
    [IsNonarchimedeanLocalField L]
    [Valuation.HasExtension (ValuativeRel.valuation K) (ValuativeRel.valuation L)]
    (t : ℝ) :
    ClassFieldTheory.herbrandFunction K
      (ValuativeRel.valuation L).valuationSubring
      (inverseHerbrandFunction K L t) = t