Module

StageAugmentation.lean

Nyll.ProCGroups.CompletedGroupAlgebra.AllFiniteAugmentation.StageAugmentation
7 declarations indexed from sourceView source ↗

Augmentation at all-finite quotient stages

This file defines augmentation on each finite coefficient-and-group stage of the all-finite system and proves its formulas on basis elements and compatibility with transition, coefficient, and functorial stage maps.

Declarations

CompletedGroupAlgebra.completedGroupAlgebraStageAugmentation

The augmentation map on a finite stage is the ring homomorphism \(R[G/U]\to R\) that sends every group-like basis element to \(1\).

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 completedGroupAlgebraStageAugmentation (R : Type u) (G : Type v) [CommRing R]
    [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
    (U : CompletedGroupAlgebraIndex G) :
    CompletedGroupAlgebraStage R G U →+* R
CompletedGroupAlgebra.completedGroupAlgebraStageAugmentation_of

The finite-stage augmentation sends every group-like basis element to one.

Source context 12 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]
omit [TopologicalSpace R] [IsTopologicalRing R] in
theorem completedGroupAlgebraStageAugmentation_of
    (U : CompletedGroupAlgebraIndex G) (q : CompletedGroupAlgebraQuotient G U) :
    completedGroupAlgebraStageAugmentation R G U (MonoidAlgebra.of R _ q) = 1
CompletedGroupAlgebra.completedGroupAlgebraStageAugmentation_single

The finite-stage augmentation sends a singleton to its coefficient.

Source context 12 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]
omit [TopologicalSpace R] [IsTopologicalRing R] in
theorem completedGroupAlgebraStageAugmentation_single
    (U : CompletedGroupAlgebraIndex G) (q : CompletedGroupAlgebraQuotient G U) (r : R) :
    completedGroupAlgebraStageAugmentation R G U (MonoidAlgebra.single q r) = r
CompletedGroupAlgebra.completedGroupAlgebraStageAugmentation_compatible

Finite-stage augmentations are compatible with transition maps.

Source context 12 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]
omit [TopologicalSpace R] [IsTopologicalRing R] in
theorem completedGroupAlgebraStageAugmentation_compatible
    {U V : CompletedGroupAlgebraIndex G} (hUV : U ≤ V) :
    (completedGroupAlgebraStageAugmentation R G U).comp
        (completedGroupAlgebraTransition R G hUV) =
      completedGroupAlgebraStageAugmentation R G V
CompletedGroupAlgebra.completedGroupAlgebraStageAugmentation_comp_stageMap

Finite-stage augmentation after the stage map is the abstract group-algebra augmentation.

Source context 12 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]
omit [TopologicalSpace R] [IsTopologicalRing R] in
theorem completedGroupAlgebraStageAugmentation_comp_stageMap
    (U : CompletedGroupAlgebraIndex G) :
    (completedGroupAlgebraStageAugmentation R G U).comp
        (completedGroupAlgebraStageMap R G U) =
      groupAlgebraAugmentation R G
CompletedGroupAlgebra.completedGroupAlgebraStageAugmentation_comp_stageCoeffMap

Finite-stage augmentation is natural in the coefficient ring.

Source context 12 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]
omit [TopologicalSpace R] [IsTopologicalRing R] in
theorem completedGroupAlgebraStageAugmentation_comp_stageCoeffMap
    (S : Type w) [CommRing S] (f : R →+* S) (U : CompletedGroupAlgebraIndex G) :
    (completedGroupAlgebraStageAugmentation S G U).comp
        (completedGroupAlgebraStageCoeffMap (R := R) (G := G) S f U) =
      f.comp (completedGroupAlgebraStageAugmentation R G U)
CompletedGroupAlgebra.completedGroupAlgebraStageAugmentation_comp_functorialStageMap

Finite-stage augmentation is natural with respect to functorial finite-stage maps.

Source context 12 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]
omit [TopologicalSpace R] [IsTopologicalRing R] in
theorem completedGroupAlgebraStageAugmentation_comp_functorialStageMap
    (φ : G →* H) (hφ : Continuous φ)
    (V : CompletedGroupAlgebraIndex H) :
    (completedGroupAlgebraStageAugmentation R H V).comp
        (completedGroupAlgebraFunctorialStageMap (G := G) (H := H) (R := R) φ hφ V) =
      completedGroupAlgebraStageAugmentation R G
        (completedGroupAlgebraComapIndex (G := G) φ hφ V)