Module

FiniteTowerBaseUnitsH2.lean

Nyll.GaloisCohomology.Kummer.FiniteTowerBaseUnitsH2
2 declarations indexed from sourceView source ↗

Base-unit coefficients along a field tower

The inclusions Kˣ → Lˣ → Nˣ give an actual equivariant coefficient map for Gal(N/L), starting with the trivial action on Kˣ.

Imports6
  • Nyll.GaloisCohomology.Kummer.FiniteCyclicBaseUnitsH2
  • Mathlib.Algebra.Category.ModuleCat.Basic
  • Mathlib.Algebra.Group.Units.Hom
  • Mathlib.Algebra.Module.LinearMap.Defs
  • Mathlib.RepresentationTheory.Rep.Basic
  • Mathlib.RepresentationTheory.Homological.GroupCohomology.Functoriality
Imported by4

Declarations

ClassFieldTower.Cohomology.finiteTowerBaseUnitsRepHom

Inclusion of base units along the two given algebra maps.

Source context 4 commands

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

open CategoryTheory
namespace ClassFieldTower.Cohomology
noncomputable section
variable (K L N : Type) [Field K] [Field L] [Field N]
  [Algebra K L] [Algebra L N]
def finiteTowerBaseUnitsRepHom :
    Rep.trivial ℤ Gal(N/L) (Additive Kˣ) ⟶ Rep.ofAlgebraAutOnUnits L N
ClassFieldTower.Cohomology.finiteTowerBaseUnitsH2Map

The induced degree-two coefficient map for the actual field tower.

Source context 4 commands

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

open CategoryTheory
namespace ClassFieldTower.Cohomology
noncomputable section
variable (K L N : Type) [Field K] [Field L] [Field N]
  [Algebra K L] [Algebra L N]
def finiteTowerBaseUnitsH2Map :
    groupCohomology (Rep.trivial ℤ Gal(N/L) (Additive Kˣ)) 2 ⟶
      groupCohomology (Rep.ofAlgebraAutOnUnits L N) 2