Module

Stage.lean

Nyll.ProCGroups.CompletedGroupAlgebra.Basic.InClass.Stage
14 declarations indexed from sourceView source ↗

Completed Group Algebra / Basic / Within a Class / Stage

This module defines the \(C\)-indexed finite group-algebra stages, their transition and coefficient-change ring homomorphisms, and the compatibility identities used by the inverse system.

Declarations

CompletedGroupAlgebra.CompletedGroupAlgebraStageInClass

A \(C\)-indexed quotient \(G/U\) determines the finite-stage group algebra \(R[G/U]\).

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
abbrev CompletedGroupAlgebraStageInClass (C : ProCGroups.FiniteGroupClass.{v})
    (R : Type u) (G : Type v) [CommRing R] [Group G] [TopologicalSpace G]
    [IsTopologicalGroup G] (U : CompletedGroupAlgebraIndexInClass G C) :
    Type (max u v)
CompletedGroupAlgebra.completedGroupAlgebraStageCoeffMapInClass

The coefficient-change map on one \(C\)-indexed completed-group-algebra stage is defined by changing coefficients.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
def completedGroupAlgebraStageCoeffMapInClass
    (C : ProCGroups.FiniteGroupClass.{v}) (S : Type w) [CommRing S]
    (f : R →+* S) (U : CompletedGroupAlgebraIndexInClass G C) :
    CompletedGroupAlgebraStageInClass C R G U →+*
      CompletedGroupAlgebraStageInClass C S G U
CompletedGroupAlgebra.completedGroupAlgebraStageCoeffMapInClass_single

At a \(C\)-indexed stage, coefficient change sends the singleton at \(q\) with coefficient \(r\) to the singleton at \(q\) with coefficient \(f(r)\).

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraStageCoeffMapInClass_single
    (C : ProCGroups.FiniteGroupClass.{v}) (S : Type w) [CommRing S]
    (f : R →+* S) (U : CompletedGroupAlgebraIndexInClass G C)
    (q : CompletedGroupAlgebraQuotientInClass G C U) (r : R) :
    completedGroupAlgebraStageCoeffMapInClass (R := R) (G := G) C S f U
        (MonoidAlgebra.single q r) =
      MonoidAlgebra.single q (f r)
CompletedGroupAlgebra.completedGroupAlgebraStageCoeffMapInClass_comp

At a \(C\)-indexed stage \(U\), changing coefficients first along \(f\) and then along \(g\) equals changing coefficients along \(g\circ f\).

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraStageCoeffMapInClass_comp
    (C : ProCGroups.FiniteGroupClass.{v}) (S : Type w) (T : Type*) [CommRing S]
    [CommRing T] (f : R →+* S) (g : S →+* T)
    (U : CompletedGroupAlgebraIndexInClass G C) :
    (completedGroupAlgebraStageCoeffMapInClass (R := S) (G := G) C T g U).comp
        (completedGroupAlgebraStageCoeffMapInClass (R := R) (G := G) C S f U) =
      completedGroupAlgebraStageCoeffMapInClass (R := R) (G := G) C T (g.comp f) U
CompletedGroupAlgebra.finite_completedGroupAlgebraStageInClass

A finite coefficient ring gives finite \(C\)-indexed completed-group-algebra stages.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem finite_completedGroupAlgebraStageInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    [Finite R] (U : CompletedGroupAlgebraIndexInClass G C) :
    Finite (CompletedGroupAlgebraStageInClass C R G U)
CompletedGroupAlgebra.completedGroupAlgebraTransitionInClass

The transition map \(R[G/V] \to R[G/U]\) in the \(C\)-indexed completed-group-algebra tower.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
def completedGroupAlgebraTransitionInClass
    (C : ProCGroups.FiniteGroupClass.{v}) (R : Type u) (G : Type v) [CommRing R]
    [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
    {U V : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V) :
    CompletedGroupAlgebraStageInClass C R G V →+*
      CompletedGroupAlgebraStageInClass C R G U
CompletedGroupAlgebra.completedGroupAlgebraTransitionInClass_of

The transition map sends group-like basis elements by quotient projection.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraTransitionInClass_of
    (C : ProCGroups.FiniteGroupClass.{v})
    {U V : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V)
    (g : CompletedGroupAlgebraQuotientInClass G C V) :
    completedGroupAlgebraTransitionInClass C R G hUV (MonoidAlgebra.of R _ g) =
      MonoidAlgebra.single ((OpenNormalSubgroupInClass.map
        (C := C) (G := G) (U := OrderDual.ofDual U) (V := OrderDual.ofDual V) hUV) g) 1
CompletedGroupAlgebra.completedGroupAlgebraTransitionInClass_single

The \(C\)-indexed transition map between finite stages sends a singleton supported at a class of the finer quotient to the singleton supported at its image in the coarser quotient, preserving the coefficient.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraTransitionInClass_single
    (C : ProCGroups.FiniteGroupClass.{v})
    {U V : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V)
    (q : CompletedGroupAlgebraQuotientInClass G C V) (r : R) :
    completedGroupAlgebraTransitionInClass C R G hUV (MonoidAlgebra.single q r) =
      MonoidAlgebra.single
        ((OpenNormalSubgroupInClass.map
          (C := C) (G := G) (U := OrderDual.ofDual U) (V := OrderDual.ofDual V) hUV) q) r
CompletedGroupAlgebra.completedGroupAlgebraTransitionInClass_id

The identity transition map in the \(C\)-indexed tower is the identity ring homomorphism.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraTransitionInClass_id
    (C : ProCGroups.FiniteGroupClass.{v}) (U : CompletedGroupAlgebraIndexInClass G C) :
    completedGroupAlgebraTransitionInClass C R G (le_rfl : U ≤ U) = RingHom.id _
CompletedGroupAlgebra.completedGroupAlgebraTransitionInClass_comp

Transition maps in the \(C\)-indexed tower compose as expected.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraTransitionInClass_comp
    (C : ProCGroups.FiniteGroupClass.{v})
    {U V W : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V) (hVW : V ≤ W) :
    (completedGroupAlgebraTransitionInClass C R G hUV).comp
        (completedGroupAlgebraTransitionInClass C R G hVW) =
      completedGroupAlgebraTransitionInClass C R G (hUV.trans hVW)
CompletedGroupAlgebra.completedGroupAlgebraStageCoeffMapInClass_compatible

\(C\)-indexed stage transitions commute with coefficient change.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraStageCoeffMapInClass_compatible
    (C : ProCGroups.FiniteGroupClass.{v}) (S : Type w) [CommRing S] (f : R →+* S)
    {U V : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V) :
    (completedGroupAlgebraStageCoeffMapInClass (R := R) (G := G) C S f U).comp
        (completedGroupAlgebraTransitionInClass C R G hUV) =
      (completedGroupAlgebraTransitionInClass C S G hUV).comp
        (completedGroupAlgebraStageCoeffMapInClass (R := R) (G := G) C S f V)
CompletedGroupAlgebra.completedGroupAlgebraStageCoeffMapInClass_transition_comp

Two coefficient changes and two \(C\)-indexed group-quotient transitions compose as the combined change and combined transition.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraStageCoeffMapInClass_transition_comp
    (C : ProCGroups.FiniteGroupClass.{v}) (S : Type w) (T : Type*) [CommRing S]
    [CommRing T] (f : R →+* S) (g : S →+* T)
    {U V W : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V) (hVW : V ≤ W) :
    ((completedGroupAlgebraStageCoeffMapInClass (R := S) (G := G) C T g U).comp
        (completedGroupAlgebraTransitionInClass C S G hUV)).comp
        ((completedGroupAlgebraStageCoeffMapInClass (R := R) (G := G) C S f V).comp
          (completedGroupAlgebraTransitionInClass C R G hVW)) =
      (completedGroupAlgebraStageCoeffMapInClass (R := R) (G := G) C T (g.comp f) U).comp
        (completedGroupAlgebraTransitionInClass C R G (hUV.trans hVW))
CompletedGroupAlgebra.completedGroupAlgebraTransitionInClass_smul

Transition maps commute with scalar multiplication by coefficients.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraTransitionInClass_smul
    (C : ProCGroups.FiniteGroupClass.{v})
    {U V : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V)
    (r : R) (x : CompletedGroupAlgebraStageInClass C R G V) :
    completedGroupAlgebraTransitionInClass C R G hUV (r • x) =
      r • completedGroupAlgebraTransitionInClass C R G hUV x
CompletedGroupAlgebra.completedGroupAlgebraTransitionInClass_algebraMap

Transition maps commute with the coefficient algebra maps.

Source context 10 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
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R]
section InClass
theorem completedGroupAlgebraTransitionInClass_algebraMap
    (C : ProCGroups.FiniteGroupClass.{v})
    {U V : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V) (r : R) :
    completedGroupAlgebraTransitionInClass C R G hUV
        (algebraMap R (CompletedGroupAlgebraStageInClass C R G V) r) =
      algebraMap R (CompletedGroupAlgebraStageInClass C R G U) r