Module

LocalMaximalKummerExtension.lean

Nyll.GaloisCohomology.Kummer.Concrete.LocalMaximalKummerExtension
2 declarations indexed from sourceView source ↗

Maximal finite Kummer extensions of local fields

For a positive integer n that is nonzero in a nonarchimedean local field, the Kummer extension obtained by adjoining all n-th roots is finite.

Declarations

KummerTheory.finite_maximalRestrictedRadicalQuotient

The maximal restricted radical quotient is finite when the exponent is nonzero in the local field.

Source context 4 commands

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

noncomputable section
universe v
namespace KummerTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
theorem finite_maximalRestrictedRadicalQuotient
    (n : ℕ+) (hnK : ((n : ℕ) : K) ≠ 0) :
    Finite (RestrictedRadicalQuotient n (maximalKummerSubgroup K n))
KummerTheory.maximalKummerRadicalExtension_finiteDimensional

The maximal exponent-n Kummer extension is finite-dimensional.

Source context 5 commands

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

noncomputable section
universe v
namespace KummerTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable {Omega : Type v} [Field Omega] [Algebra K Omega] [IsSepClosure K Omega]
theorem maximalKummerRadicalExtension_finiteDimensional
    (n : ℕ+) (hnK : ((n : ℕ) : K) ≠ 0)
    (hmu : (primitiveRoots (n : ℕ) K).Nonempty) :
    FiniteDimensional K
      (kummerRadicalExtension (K := K) (Omega := Omega) n
        (maximalKummerSubgroup K n).1)