Module

FiniteAbelianLocalReciprocityQuotientEquivOfArtin.lean

Nyll.ClassFieldTheory.Theorems.LocalClassFieldTheory.FiniteAbelianLocalReciprocityQuotientEquivOfArtin
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The norm quotient induced by a specified finite local Artin map

The first isomorphism theorem determines the quotient equivalence from any specified continuous surjective homomorphism with the field-norm kernel. This is distinct from uniqueness of the Artin map itself.

Imports7
Imported by2

Declarations

ClassFieldTheory.finiteAbelianLocalReciprocity_quotientEquiv_of_artin

Any specified continuous surjective homomorphism with the field-norm kernel induces one and only one continuous equivalence of the norm quotient. The equivalence evaluates to the specified map on every quotient class.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem finiteAbelianLocalReciprocity_quotientEquiv_of_artin
    (K : Type u) (L : Type v)
    [Field K] [Field L] [Algebra K L]
    [FiniteDimensional K L] [IsAbelianGalois K L]
    [ValuativeRel K] [TopologicalSpace K]
    [IsNonarchimedeanLocalField K]
    (artin : Kˣ →ₜ* (L ≃ₐ[K] L))
    (hsurj : Function.Surjective artin)
    (hker : artin.ker = fieldNormSubgroup K L) :
    ∃! e : FieldNormQuotient K L ≃ₜ* (L ≃ₐ[K] L),
      ∀ x : Kˣ, e (QuotientGroup.mk' (fieldNormSubgroup K L) x) = artin x