Module

RayClassSubgroupQuotientEquiv.lean

Nyll.ClassFieldTheory.Definitions.ConductorsAndRayClassFields.RayClassSubgroupQuotientEquiv
1 declaration indexed from sourceView source ↗

The quotient induced by a ray-class Artin map

The prescribed subgroup is identified with the Artin kernel before applying the first isomorphism theorem.

Declarations

ClassFieldTheory.rayClassSubgroupQuotientEquiv

The isomorphism induced by the Artin map of a ray-class realization.

Source context 4 commands

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

open scoped NumberField
noncomputable section
namespace ClassFieldTheory
universe u
def rayClassSubgroupQuotientEquiv
    (K : Type u) [Field K] [NumberField K]
    (m : RayClassModulus K) (H : Subgroup (RayClassGroup m))
    (R : RayClassSubgroupRealization K m H) :
    (RayClassGroup m ⧸ H) ≃* (R.extension ≃ₐ[K] R.extension)