Module

Maps.lean

Nyll.ProCGroups.CompletedGroupAlgebra.InClassFunctoriality.Maps
14 declarations indexed from sourceView source ↗

Completed Group Algebra / Functoriality Within a Class / Maps

This module lifts hereditary \(C\)-indexed finite-stage maps to the named completed carrier and proves their algebraic, topological, and dense-subalgebra characterizations.

Declarations

CompletedGroupAlgebra.completedGroupAlgebraMapInClass

A continuous homomorphism of groups induces a ring homomorphism on \(C\)-indexed completed group algebras, when \(C\) is hereditary.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
def completedGroupAlgebraMapInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
    (φ : G →* H) (hφ : Continuous φ) :
    CompletedGroupAlgebraInClass C R G →+* CompletedGroupAlgebraInClass C R H where
  toFun x :=
    (completedGroupAlgebraInClassCompatibleFamilyEquiv
      (R := R) (G := H) C).symm
      ((completedGroupAlgebraSystemInClass C R H).inverseLimitLift
        (fun V x =>
          completedGroupAlgebraFunctorialStageMapInClass
            (G := G) (H := H) C hHer (R := R) φ hφ V
            (completedGroupAlgebraProjectionInClass C R G
              (completedGroupAlgebraComapIndexInClass
                (G := G) (H := H) C hHer φ hφ V) x))
        (by
          intro V W hVW
          funext x
          have hcomp := congrFun
            (congrArg DFunLike.coe
              (completedGroupAlgebraFunctorialStageMapInClass_transition
                (R := R) (G := G) (H := H) C hHer φ hφ hVW))
            (completedGroupAlgebraProjectionInClass C R G
              (completedGroupAlgebraComapIndexInClass
                (G := G) (H := H) C hHer φ hφ W) x)
          rw [RingHom.comp_apply, RingHom.comp_apply] at hcomp
          simp only
          rw [← completedGroupAlgebraProjectionInClass_compatible
            (R := R) (G := G) C
            (completedGroupAlgebraComapIndexInClass_mono
              (G := G) (H := H) C hHer φ hφ hVW) x]
          exact hcomp) x)
  map_zero' := by
    apply completedGroupAlgebraInClass_ext (R := R) (G := H) C
    intro V
    exact map_zero (completedGroupAlgebraFunctorialStageMapInClass
      (G := G) (H := H) C hHer (R := R) φ hφ V)
  map_one' := by
    apply completedGroupAlgebraInClass_ext (R := R) (G := H) C
    intro V
    exact map_one (completedGroupAlgebraFunctorialStageMapInClass
      (G := G) (H := H) C hHer (R := R) φ hφ V)
  map_add' x y := by
    apply completedGroupAlgebraInClass_ext (R := R) (G := H) C
    intro V
    exact map_add (completedGroupAlgebraFunctorialStageMapInClass
      (G := G) (H := H) C hHer (R := R) φ hφ V)
      (completedGroupAlgebraProjectionInClass C R G
        (completedGroupAlgebraComapIndexInClass (G := G) (H := H) C hHer φ hφ V) x)
      (completedGroupAlgebraProjectionInClass C R G
        (completedGroupAlgebraComapIndexInClass (G := G) (H := H) C hHer φ hφ V) y)
  map_mul' x y := by
    apply completedGroupAlgebraInClass_ext (R := R) (G := H) C
    intro V
    exact map_mul (completedGroupAlgebraFunctorialStageMapInClass
      (G := G) (H := H) C hHer (R := R) φ hφ V)
      (completedGroupAlgebraProjectionInClass C R G
        (completedGroupAlgebraComapIndexInClass (G := G) (H := H) C hHer φ hφ V) x)
      (completedGroupAlgebraProjectionInClass C R G
        (completedGroupAlgebraComapIndexInClass (G := G) (H := H) C hHer φ hφ V) y)
CompletedGroupAlgebra.completedGroupAlgebraProjectionInClass_map

The in-class completed group-algebra map is characterized by its finite-stage projections.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraProjectionInClass_map
    (C : ProCGroups.FiniteGroupClass.{v})
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    (φ : G →* H) (hφ : Continuous φ)
    (V : CompletedGroupAlgebraIndexInClass H C) (x : CompletedGroupAlgebraInClass C R G) :
    completedGroupAlgebraProjectionInClass C R H V
        (completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ x) =
      completedGroupAlgebraFunctorialStageMapInClass
        (G := G) (H := H) C hHer (R := R) φ hφ V
        (completedGroupAlgebraProjectionInClass C R G
          (completedGroupAlgebraComapIndexInClass (G := G) (H := H) C hHer φ hφ V) x)
CompletedGroupAlgebra.completedGroupAlgebraMapAlgHomInClass

A continuous group homomorphism \(\varphi:G\to H\) induces an \(R\)-algebra homomorphism between the corresponding \(C\)-indexed completed group algebras.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
def completedGroupAlgebraMapAlgHomInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
    (φ : G →* H) (hφ : Continuous φ) :
    CompletedGroupAlgebraInClass C R G →ₐ[R] CompletedGroupAlgebraInClass C R H where
  toRingHom := completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ
  commutes' := by
    intro r
    apply completedGroupAlgebraInClass_ext (R := R) (G := H) C
    intro V
    change completedGroupAlgebraFunctorialStageMapInClass
        (G := G) (H := H) C hHer (R := R) φ hφ V
        (algebraMap R
          (CompletedGroupAlgebraStageInClass C R G
            (completedGroupAlgebraComapIndexInClass
              (G := G) (H := H) C hHer φ hφ V)) r) =
      algebraMap R (CompletedGroupAlgebraStageInClass C R H V) r
    exact completedGroupAlgebraFunctorialStageMapInClass_algebraMap
      (R := R) (G := G) (H := H) C hHer φ hφ V r
CompletedGroupAlgebra.completedGroupAlgebraMapAlgHomInClass_apply

Evaluating the algebra homomorphism induced by \(\varphi\) at \(x\) gives completedGroupAlgebraMapInClass applied to \(x\).

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapAlgHomInClass_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    (φ : G →* H) (hφ : Continuous φ) (x : CompletedGroupAlgebraInClass C R G) :
    completedGroupAlgebraMapAlgHomInClass (G := G) (H := H) C hHer R φ hφ x =
      completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ x
CompletedGroupAlgebra.continuous_completedGroupAlgebraMapInClass

The induced \(C\)-indexed completed-group-algebra map is continuous.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem continuous_completedGroupAlgebraMapInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    (φ : G →* H) (hφ : Continuous φ) :
    Continuous (completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ)
CompletedGroupAlgebra.completedGroupAlgebraMapInClass_comp_toCompletedGroupAlgebraInClass

The in-class completed group-algebra map composes with the dense abstract map as expected.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapInClass_comp_toCompletedGroupAlgebraInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    (φ : G →* H) (hφ : Continuous φ) :
    (completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ).comp
        (toCompletedGroupAlgebraInClassRingHom C R G) =
      (toCompletedGroupAlgebraInClassRingHom C R H).comp
        (MonoidAlgebra.mapDomainRingHom R φ)
CompletedGroupAlgebra.completedGroupAlgebraMapInClass_surjective_of_surjective

A surjective continuous homomorphism onto a pro-\(C\) group induces a surjective map on \(C\)-indexed completed group algebras.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapInClass_surjective_of_surjective
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C)
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    [CompactSpace R] [T2Space R] [TotallyDisconnectedSpace R]
    (hH : HasOpenNormalBasisInClass C H)
    (φ : G →* H) (hφ : Continuous φ) (hφsurj : Function.Surjective φ) :
    Function.Surjective
      (completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ)
CompletedGroupAlgebra.completedGroupAlgebraInClassRingHom_ext_of_comp_toCompleted

Continuous ring homomorphisms out of \(\widehat{R[G]}_C\) are determined by their values on the dense abstract group algebra.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraInClassRingHom_ext_of_comp_toCompleted
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C)
    [CompactSpace R] [T2Space R] [TotallyDisconnectedSpace R]
    (hG : HasOpenNormalBasisInClass C G)
    {f g : CompletedGroupAlgebraInClass C R G →+*
      CompletedGroupAlgebraInClass C R H}
    (hf : Continuous f) (hg : Continuous g)
    (hfg : f.comp (toCompletedGroupAlgebraInClassRingHom C R G) =
      g.comp (toCompletedGroupAlgebraInClassRingHom C R G)) :
    f = g
CompletedGroupAlgebra.completedGroupAlgebraMapInClass_id

Identity law for the \(C\)-indexed completed-group-algebra functor.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapInClass_id
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C)
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    [CompactSpace R] [T2Space R] [TotallyDisconnectedSpace R]
    (hG : HasOpenNormalBasisInClass C G) :
    completedGroupAlgebraMapInClass (G := G) (H := G) C hHer R
        (MonoidHom.id G) continuous_id =
      RingHom.id (CompletedGroupAlgebraInClass C R G)
CompletedGroupAlgebra.completedGroupAlgebraMapAlgHomInClass_id

Identity law for the \(C\)-indexed completed-group-algebra functor, as an \(R\)-algebra homomorphism.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapAlgHomInClass_id
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C)
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    [CompactSpace R] [T2Space R] [TotallyDisconnectedSpace R]
    (hG : HasOpenNormalBasisInClass C G) :
    completedGroupAlgebraMapAlgHomInClass (G := G) (H := G) C hHer R
        (MonoidHom.id G) continuous_id =
      AlgHom.id R (CompletedGroupAlgebraInClass C R G)
CompletedGroupAlgebra.completedGroupAlgebraMapInClass_comp

Composition law for the \(C\)-indexed completed-group-algebra functor.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapInClass_comp
    {K : Type v} [Group K] [TopologicalSpace K] [IsTopologicalGroup K]
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C)
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    [CompactSpace R] [T2Space R] [TotallyDisconnectedSpace R]
    (hG : HasOpenNormalBasisInClass C G)
    (φ : G →* H) (hφ : Continuous φ) (ψ : H →* K) (hψ : Continuous ψ) :
    (completedGroupAlgebraMapInClass (G := H) (H := K) C hHer R ψ hψ).comp
        (completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ) =
      completedGroupAlgebraMapInClass (G := G) (H := K) C hHer R
        (ψ.comp φ) (hψ.comp hφ)
CompletedGroupAlgebra.completedGroupAlgebraMapAlgHomInClass_comp

Composition law for the \(C\)-indexed completed-group-algebra functor, as an \(R\)-algebra homomorphism.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapAlgHomInClass_comp
    {K : Type v} [Group K] [TopologicalSpace K] [IsTopologicalGroup K]
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C)
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    [CompactSpace R] [T2Space R] [TotallyDisconnectedSpace R]
    (hG : HasOpenNormalBasisInClass C G)
    (φ : G →* H) (hφ : Continuous φ) (ψ : H →* K) (hψ : Continuous ψ) :
    (completedGroupAlgebraMapAlgHomInClass (G := H) (H := K) C hHer R ψ hψ).comp
        (completedGroupAlgebraMapAlgHomInClass (G := G) (H := H) C hHer R φ hφ) =
      completedGroupAlgebraMapAlgHomInClass (G := G) (H := K) C hHer R
        (ψ.comp φ) (hψ.comp hφ)
CompletedGroupAlgebra.completedGroupAlgebraMapInClass_toCompletedGroupAlgebraInClass_of

The in-class completed group-algebra map sends group-like elements to group-like elements.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapInClass_toCompletedGroupAlgebraInClass_of
    (C : ProCGroups.FiniteGroupClass.{v})
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    (φ : G →* H) (hφ : Continuous φ) (g : G) :
    completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ
        (toCompletedGroupAlgebraInClass C R G (MonoidAlgebra.of R G g)) =
      toCompletedGroupAlgebraInClass C R H (MonoidAlgebra.of R H (φ g))
CompletedGroupAlgebra.completedGroupAlgebraMapInClass_toCompletedGroupAlgebraInClass_sub_one_of

The in-class completed group-algebra map sends group-like augmentation generators to their images.

Source context 11 commands

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

open scoped Topology
namespace CompletedGroupAlgebra
noncomputable section
open ProCGroups
open ProCGroups.ProC
open ProCGroups.InverseSystems
open ProCGroups.Completion
universe u v w
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem completedGroupAlgebraMapInClass_toCompletedGroupAlgebraInClass_sub_one_of
    (C : ProCGroups.FiniteGroupClass.{v})
    (hHer : ProCGroups.FiniteGroupClass.Hereditary C)
    (φ : G →* H) (hφ : Continuous φ) (g : G) :
    completedGroupAlgebraMapInClass (G := G) (H := H) C hHer R φ hφ
        (toCompletedGroupAlgebraInClass C R G (MonoidAlgebra.of R G g) - 1) =
      toCompletedGroupAlgebraInClass C R H (MonoidAlgebra.of R H (φ g)) - 1