Module

CanonicalAugmentation.lean

Nyll.ProCGroups.CompletedGroupAlgebra.Augmentation.CanonicalAugmentation
12 declarations indexed from sourceView source ↗

Canonical augmentation of the in-class completion

Compatible finite-stage augmentations assemble into the canonical augmentation of the in-class completed group algebra. This file proves its projection, coefficient-map, continuity, and surjectivity properties.

Declarations

CompletedGroupAlgebra.completedGroupAlgebraAugmentationAtInClass

The \(C\)-indexed completed augmentation evaluated at a finite stage.

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 completedGroupAlgebraAugmentationAtInClass
    (C : ProCGroups.FiniteGroupClass.{v}) (R : Type u) (G : Type v) [CommRing R]
    [TopologicalSpace R] [IsTopologicalRing R] [Group G] [TopologicalSpace G]
    [IsTopologicalGroup G]
    (U : CompletedGroupAlgebraIndexInClass G C) :
    CompletedGroupAlgebraInClass C R G → R
CompletedGroupAlgebra.completedGroupAlgebraAugmentationAtInClass_eq_of_le

The augmentation value read at a finer in-class stage agrees after transition.

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 completedGroupAlgebraAugmentationAtInClass_eq_of_le
    (C : ProCGroups.FiniteGroupClass.{v})
    {U V : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V)
    (x : CompletedGroupAlgebraInClass C R G) :
    completedGroupAlgebraAugmentationAtInClass C R G  U x =
      completedGroupAlgebraAugmentationAtInClass C R G  V x
CompletedGroupAlgebra.completedGroupAlgebraCanonicalAugmentationInClass

The canonical augmentation on the \(C\)-indexed completed 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]
def completedGroupAlgebraCanonicalAugmentationInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C] :
    CompletedGroupAlgebraInClass C R G →+* R
CompletedGroupAlgebra.completedGroupAlgebraCanonicalAugmentationInClass_eq_at

The in-class canonical augmentation can be computed at any in-class stage.

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 completedGroupAlgebraCanonicalAugmentationInClass_eq_at
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
    (U : CompletedGroupAlgebraIndexInClass G C) (x : CompletedGroupAlgebraInClass C R G) :
    completedGroupAlgebraCanonicalAugmentationInClass (R := R) (G := G) C x =
      completedGroupAlgebraAugmentationAtInClass C R G  U x
CompletedGroupAlgebra.completedGroupAlgebraStageAugmentationInClass_comp_projectionInClass

Stage augmentation after projection is the in-class canonical augmentation.

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 completedGroupAlgebraStageAugmentationInClass_comp_projectionInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
    (U : CompletedGroupAlgebraIndexInClass G C) :
    (completedGroupAlgebraStageAugmentationInClass C R G U).comp
        (completedGroupAlgebraProjectionInClass C R G U) =
      completedGroupAlgebraCanonicalAugmentationInClass (R := R) (G := G) C
CompletedGroupAlgebra.canonicalAugmentationInClass_toCompleted

The in-class canonical augmentation extends the abstract augmentation on the dense algebraic map.

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 canonicalAugmentationInClass_toCompleted
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C] (x : MonoidAlgebra R G) :
    completedGroupAlgebraCanonicalAugmentationInClass (R := R) (G := G) C
        (toCompletedGroupAlgebraInClass C R G x) =
      groupAlgebraAugmentation R G x
CompletedGroupAlgebra.completedGACanonicalAugmentationInClass_comp_toCompletedGAInClass

Composing the dense in-class map with canonical augmentation gives abstract augmentation.

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 completedGACanonicalAugmentationInClass_comp_toCompletedGAInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C] :
    (completedGroupAlgebraCanonicalAugmentationInClass (R := R) (G := G) C ).comp
        (toCompletedGroupAlgebraInClassRingHom C R G) =
      groupAlgebraAugmentation R G
CompletedGroupAlgebra.completedGroupAlgebraCanonicalAugmentationInClass_comp_coeffMapInClass

In-class canonical augmentation is natural in the coefficient ring.

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 completedGroupAlgebraCanonicalAugmentationInClass_comp_coeffMapInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
    (S : Type w) [CommRing S] [TopologicalSpace S] [IsTopologicalRing S]
    (f : R →+* S) :
    (completedGroupAlgebraCanonicalAugmentationInClass (R := S) (G := G) C ).comp
        (completedGroupAlgebraCoeffMapInClass (R := R) (G := G) C S f) =
      f.comp (completedGroupAlgebraCanonicalAugmentationInClass (R := R) (G := G) C )
CompletedGroupAlgebra.completedGroupAlgebraCanonicalAugmentationInClass_algebraMap

The in-class canonical augmentation sends scalar algebra-map elements to their scalar.

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 completedGroupAlgebraCanonicalAugmentationInClass_algebraMap
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C] (r : R) :
    completedGroupAlgebraCanonicalAugmentationInClass (R := R) (G := G) C
        (algebraMap R (CompletedGroupAlgebraInClass C R G) r) = r
CompletedGroupAlgebra.completedGroupAlgebraCanonicalAugmentationInClass_surjective

The \(C\)-indexed canonical augmentation \(\varepsilon_C:\widehat{R[G]}_C\to R\) is surjective.

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 completedGroupAlgebraCanonicalAugmentationInClass_surjective
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C] :
    Function.Surjective
      (completedGroupAlgebraCanonicalAugmentationInClass (R := R) (G := G) C )
CompletedGroupAlgebra.continuous_completedGroupAlgebraCanonicalAugmentationInClass

The \(C\)-indexed canonical augmentation is continuous for the inverse-limit topology on \(\widehat{R[G]}_C\).

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_completedGroupAlgebraCanonicalAugmentationInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C] :
    Continuous (completedGroupAlgebraCanonicalAugmentationInClass (R := R) (G := G) C )
CompletedGroupAlgebra.completedGroupAlgebraInClass_hasCompletedGroupAlgebraAugmentation

The \(C\)-indexed completed group algebra carries the standard model-independent augmentation package.

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 completedGroupAlgebraInClass_hasCompletedGroupAlgebraAugmentation
    (C : ProCGroups.FiniteGroupClass.{v})
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C] :
    hasCompletedGroupAlgebraAugmentation R G (CompletedGroupAlgebraInClass C R G)
      (toCompletedGroupAlgebraInClassRingHom C R G)