Module

UnitsCohomologyCongr.lean

Nyll.GaloisCohomology.Kummer.UnitsCohomologyCongr
1 declaration indexed from sourceView source ↗

Unit cohomology under a field isomorphism

Conjugation identifies the automorphism groups, while the same field isomorphism identifies their actual unit representations.

Imports5
  • Mathlib.Algebra.Algebra.Equiv
  • Mathlib.Algebra.Group.Units.Equiv
  • Mathlib.Algebra.Module.Equiv.Basic
  • Mathlib.RepresentationTheory.Rep.Basic
  • Mathlib.RepresentationTheory.Homological.GroupCohomology.Functoriality
Imported by3

Declarations

ClassFieldTower.Cohomology.unitsCohomologyCongrTop

An actual algebra equivalence transports field-unit cohomology in every degree.

Source context 2 commands

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

open CategoryTheory
namespace ClassFieldTower.Cohomology
def unitsCohomologyCongrTop
    (K L M : Type) [Field K] [Field L] [Field M] [Algebra K L] [Algebra K M]
    (e : L ≃ₐ[K] M) (n : ℕ) :
    groupCohomology (Rep.ofAlgebraAutOnUnits K L) n ≅
      groupCohomology (Rep.ofAlgebraAutOnUnits K M) n