Module

InflationTransgressionExact.lean

Nyll.GaloisCohomology.ProP.InflationTransgressionExact
4 declarations indexed from sourceView source ↗

Continuous inflation--transgression exactness in degree two

For an open normal subgroup, continuous transgression has range exactly the kernel of degree-two inflation. The reverse inclusion is proved at cochain level by restricting a continuous primitive of the inflated cocycle.

Declarations

ClassFieldTower.Cohomology.normalizedCocycle_sub
Source context 12 commands

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

open CategoryTheory TopRep ContRepresentation
open scoped Topology
namespace ClassFieldTower.Cohomology
open ProCGroups ProCGroups.ProC
open ClassFieldTower.ProP
open ClassFieldTower.ProP.FreeProPH2Cocycle
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
omit [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G] in
theorem normalizedCocycle_sub
    {H : Type u} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
    (z w : trivialZModPCocyclesLifted p H 2) (g h : H) :
    normalizedCocycle (z - w) g h =
      normalizedCocycle z g h - normalizedCocycle w g h
ClassFieldTower.Cohomology.normalizedCocycle_continuousTransgression
Source context 12 commands

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

open CategoryTheory TopRep ContRepresentation
open scoped Topology
namespace ClassFieldTower.Cohomology
open ProCGroups ProCGroups.ProC
open ClassFieldTower.ProP
open ClassFieldTower.ProP.FreeProPH2Cocycle
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
omit [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G] in
theorem normalizedCocycle_continuousTransgression
    (U : OpenNormalSubgroupInClass (FiniteGroupClass.pGroup p) G)
    (chi : InvariantContinuousH1 U)
    (q r : G ⧸ (U.1 : Subgroup G)) :
    normalizedCocycle (continuousTransgressionHomogeneousCocycle U chi) q r =
      ULift.up (transgressionFactor (U.1 : Subgroup G)
        (characterOfH1 chi.1).toMonoidHom q r) -
      ULift.up (transgressionFactor (U.1 : Subgroup G)
        (characterOfH1 chi.1).toMonoidHom 1 1)
ClassFieldTower.Cohomology.continuousTransgressionClass_invariantContinuousH1OfInflationPrimitive

A reconstructed invariant character transgresses to the original quotient cocycle class.

Source context 12 commands

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

open CategoryTheory TopRep ContRepresentation
open scoped Topology
namespace ClassFieldTower.Cohomology
open ProCGroups ProCGroups.ProC
open ClassFieldTower.ProP
open ClassFieldTower.ProP.FreeProPH2Cocycle
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
omit [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G] in
theorem continuousTransgressionClass_invariantContinuousH1OfInflationPrimitive
    (U : OpenNormalSubgroupInClass (FiniteGroupClass.pGroup p) G)
    (z : trivialZModPCocyclesLifted p (G ⧸ (U.1 : Subgroup G)) 2)
    (c : (trivialZModPCochainsLifted p G).X 1)
    (hc : ((trivialZModPCochainsLifted p G).d 1 2).hom c =
      (((trivialZModPCochainsMapLifted p
        (OpenNormalSubgroupInClass.quotientProj U)).f 2).hom
          (((trivialZModPCochainsLifted p
            (G ⧸ (U.1 : Subgroup G))).iCycles 2).hom z))) :
    continuousTransgressionClass U
        (invariantContinuousH1OfInflationPrimitive U z c hc) =
      ContinuousCohomology.π
        (trivialZModPLifted p (G ⧸ (U.1 : Subgroup G))) 2 z
ClassFieldTower.Cohomology.continuousTransgression_range_eq_degreeTwoInflation_ker

Continuous Hochschild--Serre exactness at degree two for an open normal subgroup.

Source context 12 commands

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

open CategoryTheory TopRep ContRepresentation
open scoped Topology
namespace ClassFieldTower.Cohomology
open ProCGroups ProCGroups.ProC
open ClassFieldTower.ProP
open ClassFieldTower.ProP.FreeProPH2Cocycle
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
omit [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G] in
theorem continuousTransgression_range_eq_degreeTwoInflation_ker
    (U : OpenNormalSubgroupInClass (FiniteGroupClass.pGroup p) G) :
    LinearMap.range (continuousTransgressionLinearMap U) =
      LinearMap.ker (degreeTwoInflationLinearMap U)