Module

OriginalFiniteFieldCanonicalTameEvaluation.lean

Nyll.EtaleFundamentalGroups.Inertia.OriginalFiniteFieldCanonicalTameEvaluation
2 declarations indexed from sourceView source ↗

Evaluation of original finite-field tame characters

Identifies the intrinsic canonical character with the normalized finite ideal character and evaluates the original finite-field character on its normalization inertia image.

Declarations

EtaleFundamentalGroups.Inertia.commAlgCanonicalTameCharacter_apply

The native intrinsic character is the same canonical normalized finite ideal character. The localized output is exposed only in this ring-only scope.

Source context 4 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Inertia
open SchemeTheory
universe u v w
theorem commAlgCanonicalTameCharacter_apply
    (A : Type u) [CommRing A] (B : CommAlgCat.{v} A)
    [IsDedekindDomain B] [Finite (B ≃ₐ[A] B)]
    (Q : Ideal B) [Q.IsPrime] (hQ : Q ≠ ⊥)
    (σ : commAlgIdealInertiaGroup A B Q) :
    (commAlgCanonicalTameCharacter A B Q hQ).toFun σ =
      (finiteIdealCanonicalTameCharacterGroupMap A B (B ≃ₐ[A] B) Q hQ).toFun σ
EtaleFundamentalGroups.Inertia.originalFiniteFieldCanonicalTameMorphism_apply

The original finite field character evaluates the existing native canonical character at its actual normalization inertia image. This closes the localization data before the original field tower is introduced.

Source context 4 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Inertia
open SchemeTheory
universe u v w
theorem originalFiniteFieldCanonicalTameMorphism_apply
    (A : Type u) (K : Type v) (F : Type w)
    [CommRing A] [IsDomain A] [IsDiscreteValuationRing A]
    [Field K] [Field F] [Algebra A K] [IsFractionRing A K]
    [Algebra K F] [Algebra A F] [IsScalarTower A K F]
    [FiniteDimensional K F] [IsGalois K F]
    (Q : Ideal (normalizationCommAlgCat A F)) [Q.IsMaximal]
    (σ : actualNormalizationInertiaGroup A K F Q) :
    let : IsDedekindDomain (normalizationCommAlgCat A F) :=
      integralClosure.isDedekindDomain A K F
    let : Finite (normalizationCommAlgCat A F ≃ₐ[A] normalizationCommAlgCat A F) :=
      nativeNormalization_aut_finite A K (CommAlgCat.of A F) (Field.toIsField F)
    (originalFiniteFieldCanonicalTameMorphism A K F Q).hom'.toFun σ =
      (commAlgCanonicalTameCharacter A (normalizationCommAlgCat A F) Q
        (originalFiniteNormalizationPrime_ne_bot A K F Q)).toFun
          ((originalFiniteNormalizationInertiaMorphism A K F Q).hom'.toFun σ) := by
  intro normalizationDedekind normalizationAutomorphisms
  rfl