Module

SemidirectHom.lean

Nyll.ProCGroups.FoxDifferential.Completed.FreeProC.Uniqueness.SemidirectHom
4 declarations indexed from sourceView source ↗

Fox differential: completed — free pro-\(C\) — uniqueness — semidirect hom

The principal declarations in this module are:

  • freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential

A completed crossed differential and its coefficient homomorphism combine into a semidirect homomorphism.

  • freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential_left

The semidirect homomorphism attached to a crossed differential has \(\delta\) as its left component.

  • freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential_right

The semidirect homomorphism attached to a crossed differential has \(\psi\)s its right component.

  • continuous_freeProCZCCompletedFoxSemidirectGenerator_of_crossedDifferential

If a crossed-differential semidirect homomorphism is continuous and has the standard generator coordinates, then the corresponding semidirect generator map is continuous.

Declarations

FoxDifferential.freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential

A completed crossed differential and its coefficient homomorphism combine into a semidirect homomorphism.

Source context 13 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.FreeProC
universe u
variable {C : ProCGroups.FiniteGroupClass.{u}}
variable {X F H : Type u}
variable [TopologicalSpace X]
variable [Group F] [TopologicalSpace F] [IsTopologicalGroup F]
variable [CompactSpace F] [T2Space F] [TotallyDisconnectedSpace F]
variable [DecidableEq X]
variable [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable [TopologicalSpace (ZCCompletedFoxSemidirect C X H)]
variable [IsTopologicalGroup (ZCCompletedFoxSemidirect C X H)]
def freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential
    (ψ : F →* H)
    (delta : ScalarCrossedHom (zcCompletedGroupAlgebraScalar C ψ)
      (ZCFreeFoxCoordinates C (X := X) (H := H))) :
    F →* ZCCompletedFoxSemidirect C X H where
  toFun g := { left := delta g, right := ψ g }
  map_one' := by
    apply ZCCompletedFoxSemidirect.ext
    · exact delta.map_one
    · simp only [map_one, ZCCompletedFoxSemidirect.one_right]
  map_mul' g h := by
    apply ZCCompletedFoxSemidirect.ext
    · exact delta.map_mul g h
    · simp only [map_mul, ZCCompletedFoxSemidirect.mul_right]
FoxDifferential.freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential_left

The semidirect homomorphism attached to a crossed differential has \(\delta\) as its left component.

Source context 14 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.FreeProC
universe u
variable {C : ProCGroups.FiniteGroupClass.{u}}
variable {X F H : Type u}
variable [TopologicalSpace X]
variable [Group F] [TopologicalSpace F] [IsTopologicalGroup F]
variable [CompactSpace F] [T2Space F] [TotallyDisconnectedSpace F]
variable [DecidableEq X]
variable [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable [TopologicalSpace (ZCCompletedFoxSemidirect C X H)]
variable [IsTopologicalGroup (ZCCompletedFoxSemidirect C X H)]
omit [TopologicalSpace X] [TopologicalSpace F] [IsTopologicalGroup F] [DecidableEq X]
  [TopologicalSpace (ZCCompletedFoxSemidirect C X H)]
  [IsTopologicalGroup (ZCCompletedFoxSemidirect C X H)] in
theorem freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential_left
    (ψ : F →* H)
    (delta : ScalarCrossedHom (zcCompletedGroupAlgebraScalar C ψ)
      (ZCFreeFoxCoordinates C (X := X) (H := H)))
    (g : F) :
    (freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential
      (X := X) ψ delta g).left = delta g
FoxDifferential.freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential_right

The semidirect homomorphism attached to a crossed differential has \(\psi\)s its right component.

Source context 14 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.FreeProC
universe u
variable {C : ProCGroups.FiniteGroupClass.{u}}
variable {X F H : Type u}
variable [TopologicalSpace X]
variable [Group F] [TopologicalSpace F] [IsTopologicalGroup F]
variable [CompactSpace F] [T2Space F] [TotallyDisconnectedSpace F]
variable [DecidableEq X]
variable [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable [TopologicalSpace (ZCCompletedFoxSemidirect C X H)]
variable [IsTopologicalGroup (ZCCompletedFoxSemidirect C X H)]
omit [TopologicalSpace X] [TopologicalSpace F] [IsTopologicalGroup F] [DecidableEq X]
  [TopologicalSpace (ZCCompletedFoxSemidirect C X H)]
  [IsTopologicalGroup (ZCCompletedFoxSemidirect C X H)] in
theorem freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential_right
    (ψ : F →* H)
    (delta : ScalarCrossedHom (zcCompletedGroupAlgebraScalar C ψ)
      (ZCFreeFoxCoordinates C (X := X) (H := H)))
    (g : F) :
    (freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential
      (X := X) ψ delta g).right = ψ g
FoxDifferential.continuous_freeProCZCCompletedFoxSemidirectGenerator_of_crossedDifferential

If a crossed-differential semidirect homomorphism is continuous and has the standard generator coordinates, then the corresponding semidirect generator map is continuous.

Source context 14 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.FreeProC
universe u
variable {C : ProCGroups.FiniteGroupClass.{u}}
variable {X F H : Type u}
variable [TopologicalSpace X]
variable [Group F] [TopologicalSpace F] [IsTopologicalGroup F]
variable [CompactSpace F] [T2Space F] [TotallyDisconnectedSpace F]
variable [DecidableEq X]
variable [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable [TopologicalSpace (ZCCompletedFoxSemidirect C X H)]
variable [IsTopologicalGroup (ZCCompletedFoxSemidirect C X H)]
omit [IsTopologicalGroup (ZCCompletedFoxSemidirect C X H)] in
theorem continuous_freeProCZCCompletedFoxSemidirectGenerator_of_crossedDifferential
    {ι : X → F} (hι : IsFreeProCGroup (C := C) ι)
    (ψ : F →* H)
    (delta : ScalarCrossedHom (zcCompletedGroupAlgebraScalar C ψ)
      (ZCFreeFoxCoordinates C (X := X) (H := H)))
    (hcontinuous :
      Continuous (freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential
        (X := X) ψ delta))
    (hbasis :
      ∀ x : X, delta (ι x) = Pi.single x (1 : ZCCompletedGroupAlgebra C H)) :
    Continuous (freeProCZCCompletedFoxSemidirectGenerator (C := C) (fun x : X => ψ (ι x))) := by
  have hgenerator :
      (fun x : X =>
        freeProCZCCompletedFoxSemidirectHomOfCrossedDifferential
          (X := X) ψ delta (ι x)) =
        freeProCZCCompletedFoxSemidirectGenerator (C := C) (fun x : X => ψ (ι x)) := by
    funext x
    apply ZCCompletedFoxSemidirect.ext
    · exact hbasis x
    · rfl
  rw [← hgenerator]
  exact hcontinuous.comp hι.continuous_ι