Module

LocalHilbertSymbolLaws.lean

Nyll.ClassFieldTheory.LocalClassFieldTheory.Kummer.LocalHilbertSymbolLaws
3 declarations indexed from sourceView source ↗

Kernel laws for the local Hilbert symbol

The local Hilbert-symbol character is the composite of the local Artin map, the injective character obtained by evaluating automorphisms on the chosen Kummer radical, and the equivalence that transports roots of unity back to the base field. Consequently its kernel is exactly the local norm subgroup. This also makes the induced character on the concrete norm quotient injective.

Declarations

LocalClassFieldTheory.Kummer.localHilbertSymbolHom_ker

The kernel of the local Hilbert-symbol character is exactly the norm subgroup from the associated simple Kummer extension.

Source context 7 commands

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

noncomputable section
namespace LocalClassFieldTheory
namespace Kummer
open KummerTheory
open LocalFieldTheory
variable (K : Type) [Field K]
variable [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
theorem localHilbertSymbolHom_ker
    (n : ℕ+) (hnK : ((n : ℕ) : K) ≠ 0)
    (hmu : (primitiveRoots (n : ℕ) K).Nonempty) (b : Kˣ) :
    (localHilbertSymbolHom K n hnK hmu b).ker =
      localNormSubgroup K (chosenSimpleKummerExtension K n hnK b)
LocalClassFieldTheory.Kummer.localHilbertSymbol_eq_one_iff_mem_localNormSubgroup

A local Hilbert symbol is one exactly when its first argument is a norm from the simple Kummer extension determined by its second argument.

Source context 7 commands

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

noncomputable section
namespace LocalClassFieldTheory
namespace Kummer
open KummerTheory
open LocalFieldTheory
variable (K : Type) [Field K]
variable [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
theorem localHilbertSymbol_eq_one_iff_mem_localNormSubgroup
    (n : ℕ+) (hnK : ((n : ℕ) : K) ≠ 0)
    (hmu : (primitiveRoots (n : ℕ) K).Nonempty) (a b : Kˣ) :
    localHilbertSymbol K n hnK hmu a b = 1 ↔
      a ∈ localNormSubgroup K (chosenSimpleKummerExtension K n hnK b)
LocalClassFieldTheory.Kummer.localHilbertSymbolFromNormQuotient_injective

The local Hilbert-symbol character induced on the corresponding norm quotient is injective.

Source context 7 commands

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

noncomputable section
namespace LocalClassFieldTheory
namespace Kummer
open KummerTheory
open LocalFieldTheory
variable (K : Type) [Field K]
variable [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
theorem localHilbertSymbolFromNormQuotient_injective
    (n : ℕ+) (hnK : ((n : ℕ) : K) ≠ 0)
    (hmu : (primitiveRoots (n : ℕ) K).Nonempty) (b : Kˣ) :
    Function.Injective
      (localHilbertSymbolFromNormQuotient K n hnK hmu b)