Module

MixedCharCharacterLogMinimum.lean

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

Minimal valuation in a character part of an overfield's logarithm image

The set of nonzero character eigenvectors in the intermediate field whose images are principal-unit logarithms is nonempty by a scaled normal basis. The uniform logarithmic bound and integer-valued valuation give a minimum in this actual intersection.

Declarations

LocalFieldTheory.DiscreteValuationField.MultiplicativeIntegerValuation.exists_minimal_characterEigenvector_log_image

The character eigenvectors in L that are logarithms in M have a least valuation.

Source context 2 commands

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

namespace LocalFieldTheory.DiscreteValuationField.MultiplicativeIntegerValuation
variable {K L M : Type*} [Field K] [Field L] [Field M]
  [Algebra K L] [FiniteDimensional K L] [IsGalois K L] [Algebra L M] [CharZero M]
theorem exists_minimal_characterEigenvector_log_image
    (v : _root_.Valuation M (WithZero (Multiplicative ℤ)))
    [ValuationTheory.DiscreteValuationField.Valuation.IsCompleteDiscrete v]
    (p : ℕ) [Fact p.Prime] [CharP (IsLocalRing.ResidueField v.valuationSubring) p]
    (χ : (L ≃ₐ[K] L) →* Kˣ) :
    ∃ b : Lˣ,
      (∀ σ : L ≃ₐ[K] L, σ (b : L) = (χ σ : K) • (b : L)) ∧
      (∃ u : CompleteDVF.higherPrincipalUnitGroup (completeDVFOfWithZeroValuation v) 1,
        (principalUnitLogOfMixedChar v p u).toAdd = algebraMap L M (b : L)) ∧
      ∀ c : Lˣ,
        (∀ σ : L ≃ₐ[K] L, σ (c : L) = (χ σ : K) • (c : L)) →
        (∃ u : CompleteDVF.higherPrincipalUnitGroup (completeDVFOfWithZeroValuation v) 1,
          (principalUnitLogOfMixedChar v p u).toAdd = algebraMap L M (c : L)) →
        (ofWithZeroValuation v).val (Units.map (algebraMap L M).toMonoidHom b) ≤
          (ofWithZeroValuation v).val (Units.map (algebraMap L M).toMonoidHom c)