Module

Properties.lean

Nyll.Yamaguchi26AbfaithfulGalois.HigherLocalField.Properties
3 declarations indexed from sourceView source ↗

Prime-power roots of unity and ab-faithfulness in higher local fields

The stronger joint root-finiteness and ab-faithfulness statement supporting Theorem 4.2 of Yamaguchi, arXiv:2610.05634v1.

Declarations

Yamaguchi26AbfaithfulGalois.finite_primaryComponent_of_higherLocalField

Every primary root group of a higher local field is finite.

Source context 3 commands

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

namespace Yamaguchi26AbfaithfulGalois
open ProCGroups.FiniteStepSolvableQuotients
universe u v
theorem finite_primaryComponent_of_higherLocalField
    (n : ℕ) (K : Type u) [Field K]
    (hK : ValuationTheory.IsHigherLocalField.{u, v} n K) :
    ∀ (ℓ : ℕ), ℓ.Prime → Finite (CommGroup.primaryComponent Kˣ ℓ)
Yamaguchi26AbfaithfulGalois.higher_local_field_abFaithful_of_charZero

The characteristic-zero induction uses mixed-characteristic faithfulness at the first positive residue characteristic and the residue-zero lifting theorem at each preceding level.

Source context 3 commands

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

namespace Yamaguchi26AbfaithfulGalois
open ProCGroups.FiniteStepSolvableQuotients
universe u v
theorem higher_local_field_abFaithful_of_charZero
    (n : ℕ) (K : Type u) [Field K] [CharZero K]
    (hK : ValuationTheory.IsHigherLocalField.{u, v} n K) (hn : 0 < n) :
    IsAbFaithful Gal(AlgebraicClosure K/K)
Yamaguchi26AbfaithfulGalois.higher_local_field_roots_and_abFaithful

Every higher local field has finitely many roots of ℓ-power order for each prime ℓ. In positive dimension its absolute Galois group is ab-faithful.

Source context 3 commands

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

namespace Yamaguchi26AbfaithfulGalois
open ProCGroups.FiniteStepSolvableQuotients
universe u v
theorem higher_local_field_roots_and_abFaithful
    (n : ℕ) (K : Type u) [Field K]
    (hK : ValuationTheory.IsHigherLocalField.{u, v} n K) :
    (∀ (ℓ : ℕ), ℓ.Prime → Finite (CommGroup.primaryComponent Kˣ ℓ)) ∧
      (0 < n → IsAbFaithful Gal(AlgebraicClosure K/K))