Module

ClassComparison.lean

Nyll.ProCGroups.CompletedGroupAlgebra.Basic.ClassComparison
31 declarations indexed from sourceView source ↗

Completed Group Algebra / Basic / Class Comparison

This module compares the all-finite and \(C\)-indexed named completed carriers through their canonical projections, and bundles the resulting inverse maps as ring, algebra, and topological equivalences for pro-\(C\) groups.

Declarations

CompletedGroupAlgebra.completedGroupAlgebraProjectionToStageInClass

The projection from the all-finite completion to a stage indexed by a finite quotient class \(C\), bundled as a 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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraProjectionToStageInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (U : CompletedGroupAlgebraIndexInClass G C) :
    CompletedGroupAlgebraCarrier R G →+* CompletedGroupAlgebraStageInClass C R G U
CompletedGroupAlgebra.completedGroupAlgebraProjectionToStageInClass_compatible

The all-finite projection to a \(C\)-indexed stage is compatible with the transition maps of the \(C\)-indexed 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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraProjectionToStageInClass_compatible
    (C : ProCGroups.FiniteGroupClass.{v})
    {U V : CompletedGroupAlgebraIndexInClass G C} (hUV : U ≤ V)
    (x : CompletedGroupAlgebraCarrier R G) :
    completedGroupAlgebraTransitionInClass C R G hUV
        (completedGroupAlgebraProjectionToStageInClass (R := R) (G := G) C V x) =
      completedGroupAlgebraProjectionToStageInClass (R := R) (G := G) C U x
CompletedGroupAlgebra.completedGroupAlgebraToInClass

The comparison map from the ordinary all-finite completed group algebra to the inverse limit over any finite-quotient class.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraToInClass
    (C : ProCGroups.FiniteGroupClass.{v}) :
    CompletedGroupAlgebraCarrier R G → CompletedGroupAlgebraInClass C R G
CompletedGroupAlgebra.completedGroupAlgebraToInClass_projection

Projecting the comparison map \(\widehat{R[G]}\to\widehat{R[G]}_{C}\) to a \(C\)-indexed finite stage recovers the corresponding all-finite 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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraToInClass_projection
    (C : ProCGroups.FiniteGroupClass.{v})
    (U : CompletedGroupAlgebraIndexInClass G C) (x : CompletedGroupAlgebraCarrier R G) :
    completedGroupAlgebraProjectionInClass C R G U
        (completedGroupAlgebraToInClass (R := R) (G := G) C x) =
      completedGroupAlgebraProjectionToStageInClass (R := R) (G := G) C U x
CompletedGroupAlgebra.completedGroupAlgebraToInClassRingHom

The comparison from the all-finite completed group algebra to the \(C\)-indexed inverse limit is bundled as a 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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraToInClassRingHom
    (C : ProCGroups.FiniteGroupClass.{v}) :
    CompletedGroupAlgebraCarrier R G →+* CompletedGroupAlgebraInClass C R G where
  toFun := completedGroupAlgebraToInClass (R := R) (G := G) C
  map_zero' := by
    apply completedGroupAlgebraInClass_ext (R := R) (G := G) C
    intro U
    rfl
  map_one' := by
    apply completedGroupAlgebraInClass_ext (R := R) (G := G) C
    intro U
    rfl
  map_add' x y := by
    apply completedGroupAlgebraInClass_ext (R := R) (G := G) C
    intro U
    rfl
  map_mul' x y := by
    apply completedGroupAlgebraInClass_ext (R := R) (G := G) C
    intro U
    rfl
CompletedGroupAlgebra.completedGroupAlgebraToInClassRingHom_apply

The comparison map from the all-finite completed group algebra to the \(C\)-indexed model is evaluated by reading the corresponding finite-stage coordinate.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraToInClassRingHom_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (x : CompletedGroupAlgebraCarrier R G) :
    completedGroupAlgebraToInClassRingHom (R := R) (G := G) C x =
      completedGroupAlgebraToInClass (R := R) (G := G) C x
CompletedGroupAlgebra.completedGroupAlgebraToInClassAlgHom

The comparison from the all-finite completed group algebra to the \(C\)-indexed inverse limit, as an \(R\)-algebra 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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraToInClassAlgHom
    (C : ProCGroups.FiniteGroupClass.{v}) :
    CompletedGroupAlgebraCarrier R G →ₐ[R] CompletedGroupAlgebraInClass C R G where
  toRingHom := completedGroupAlgebraToInClassRingHom (R := R) (G := G) C
  commutes' := by
    intro r
    apply completedGroupAlgebraInClass_ext (R := R) (G := G) C
    intro U
    rfl
CompletedGroupAlgebra.completedGroupAlgebraToInClassAlgHom_apply

The comparison map from the all-finite completed group algebra to the \(C\)-indexed model is evaluated by reading the corresponding finite-stage coordinate.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraToInClassAlgHom_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (x : CompletedGroupAlgebraCarrier R G) :
    completedGroupAlgebraToInClassAlgHom (R := R) (G := G) C x =
      completedGroupAlgebraToInClass (R := R) (G := G) C x
CompletedGroupAlgebra.continuous_completedGroupAlgebraToInClass

The comparison map from the all-finite completed group algebra to the \(C\)-indexed completed group algebra is continuous for the inverse-limit topology.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem continuous_completedGroupAlgebraToInClass
    (C : ProCGroups.FiniteGroupClass.{v}) :
    Continuous (completedGroupAlgebraToInClass (R := R) (G := G) C )
CompletedGroupAlgebra.completedGroupAlgebraFromInClass

For a pro-\(C\) group, the \(C\)-indexed inverse limit maps back to the ordinary all-finite completed group algebra by reading the same open-normal quotient 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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraFromInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    CompletedGroupAlgebraInClass C R G → CompletedGroupAlgebraCarrier R G
CompletedGroupAlgebra.completedGroupAlgebraFromInClass_projection

Projecting the comparison map \(\widehat{R[G]}_{C}\to\widehat{R[G]}\) to an all-finite stage recovers the matching \(C\)-indexed 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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraFromInClass_projection
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (U :
        CompletedGroupAlgebraIndex G)
    (x : CompletedGroupAlgebraInClass C R G) :
    completedGroupAlgebraProjection R G U
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x) =
      completedGroupAlgebraProjectionInClass C R G
        (completedGroupAlgebraIndexToInClass G C hForm hG U) x
CompletedGroupAlgebra.completedGroupAlgebraFromInClassRingHom

The ring-homomorphism form of the comparison map is the bundled ring map determined by the underlying coordinate formula for the completed group algebra.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraFromInClassRingHom
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    CompletedGroupAlgebraInClass C R G →+* CompletedGroupAlgebraCarrier R G where
  toFun := completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG
  map_zero' := by
    apply completedGroupAlgebra_ext (R := R) (G := G)
    intro U
    change completedGroupAlgebraProjection R G U
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG 0) =
      completedGroupAlgebraProjection R G U (0 : CompletedGroupAlgebraCarrier R G)
    rw [completedGroupAlgebraFromInClass_projection]
    exact map_zero (completedGroupAlgebraProjectionInClass C R G
      (completedGroupAlgebraIndexToInClass G C hForm hG U))
  map_one' := by
    apply completedGroupAlgebra_ext (R := R) (G := G)
    intro U
    change completedGroupAlgebraProjection R G U
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG 1) =
      completedGroupAlgebraProjection R G U (1 : CompletedGroupAlgebraCarrier R G)
    rw [completedGroupAlgebraFromInClass_projection]
    exact map_one (completedGroupAlgebraProjectionInClass C R G
      (completedGroupAlgebraIndexToInClass G C hForm hG U))
  map_add' x y := by
    apply completedGroupAlgebra_ext (R := R) (G := G)
    intro U
    change completedGroupAlgebraProjection R G U
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG (x + y)) =
      completedGroupAlgebraProjection R G U
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x +
          completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG y)
    rw [completedGroupAlgebraFromInClass_projection]
    exact map_add (completedGroupAlgebraProjectionInClass C R G
      (completedGroupAlgebraIndexToInClass G C hForm hG U)) x y
  map_mul' x y := by
    apply completedGroupAlgebra_ext (R := R) (G := G)
    intro U
    change completedGroupAlgebraProjection R G U
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG (x * y)) =
      completedGroupAlgebraProjection R G U
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x *
          completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG y)
    rw [completedGroupAlgebraFromInClass_projection]
    exact map_mul (completedGroupAlgebraProjectionInClass C R G
      (completedGroupAlgebraIndexToInClass G C hForm hG U)) x y
CompletedGroupAlgebra.completedGroupAlgebraFromInClassRingHom_apply

The comparison map from the \(C\)-indexed completed group algebra to the all-finite model is evaluated by reading the corresponding finite-stage coordinate.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraFromInClassRingHom_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraInClass C R G) :
    completedGroupAlgebraFromInClassRingHom (R := R) (G := G) C hForm hG x =
      completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x
CompletedGroupAlgebra.completedGroupAlgebraFromInClassAlgHom

The algebra homomorphism form of the comparison map is the bundled algebra map determined by the underlying coordinate formula for the completed group algebra.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraFromInClassAlgHom
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    CompletedGroupAlgebraInClass C R G →ₐ[R] CompletedGroupAlgebraCarrier R G where
  toRingHom := completedGroupAlgebraFromInClassRingHom (R := R) (G := G) C hForm hG
  commutes' := by
    intro r
    apply completedGroupAlgebra_ext (R := R) (G := G)
    intro U
    change completedGroupAlgebraProjection R G U
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG
          (algebraMap R (CompletedGroupAlgebraInClass C R G) r)) =
      completedGroupAlgebraProjection R G U (algebraMap R (CompletedGroupAlgebraCarrier R G) r)
    rw [completedGroupAlgebraFromInClass_projection]
    change completedGroupAlgebraProjectionInClass C R G
        (completedGroupAlgebraIndexToInClass G C hForm hG U)
        (algebraMap R (CompletedGroupAlgebraInClass C R G) r) =
      algebraMap R (CompletedGroupAlgebraStage R G U) r
    exact completedGroupAlgebraProjectionInClass_algebraMap (R := R) (G := G) C
      (completedGroupAlgebraIndexToInClass G C hForm hG U) r
CompletedGroupAlgebra.completedGroupAlgebraFromInClassAlgHom_apply

The comparison map from the \(C\)-indexed completed group algebra to the all-finite model is evaluated by reading the corresponding finite-stage coordinate.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraFromInClassAlgHom_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraInClass C R G) :
    completedGroupAlgebraFromInClassAlgHom (R := R) (G := G) C hForm hG x =
      completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x
CompletedGroupAlgebra.continuous_completedGroupAlgebraFromInClass

The comparison map from the \(C\)-indexed completed group algebra to the all-finite completed group algebra is continuous for the inverse-limit topology.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem continuous_completedGroupAlgebraFromInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    Continuous (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG)
CompletedGroupAlgebra.completedGroupAlgebraFromInClass_toInClass

The composite from a \(C\)-indexed completion to the all-finite completion and back is the identity on the \(C\)-indexed completion.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraFromInClass_toInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraCarrier R G) :
    completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG
        (completedGroupAlgebraToInClass (R := R) (G := G) C x) = x
CompletedGroupAlgebra.completedGroupAlgebraToInClass_fromInClass

The composite from the all-finite completion to the \(C\)-indexed completion and back is the identity on the all-finite completion.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraToInClass_fromInClass
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraInClass C R G) :
    completedGroupAlgebraToInClass (R := R) (G := G) C
        (completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x) = x
CompletedGroupAlgebra.completedGroupAlgebraFromInClassRingHom_comp_toInClassRingHom

The two comparison ring homomorphisms are inverse to one another after composition.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraFromInClassRingHom_comp_toInClassRingHom
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    (completedGroupAlgebraFromInClassRingHom (R := R) (G := G) C hForm hG).comp
        (completedGroupAlgebraToInClassRingHom (R := R) (G := G) C ) =
      RingHom.id (CompletedGroupAlgebraCarrier R G)
CompletedGroupAlgebra.completedGroupAlgebraToInClassRingHom_comp_fromInClassRingHom

The two comparison ring homomorphisms are inverse to one another after composition.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraToInClassRingHom_comp_fromInClassRingHom
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    (completedGroupAlgebraToInClassRingHom (R := R) (G := G) C ).comp
        (completedGroupAlgebraFromInClassRingHom (R := R) (G := G) C hForm hG) =
      RingHom.id (CompletedGroupAlgebraInClass C R G)
CompletedGroupAlgebra.completedGroupAlgebraInClassRingEquiv

For a pro-\(C\) group, the all-finite and \(C\)-indexed completed group algebras are the same ring, via the comparison 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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraInClassRingEquiv
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    CompletedGroupAlgebraCarrier R G ≃+* CompletedGroupAlgebraInClass C R G where
  toFun := completedGroupAlgebraToInClass (R := R) (G := G) C
  invFun := completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG
  left_inv := by
    intro x
    exact completedGroupAlgebraFromInClass_toInClass (R := R) (G := G) C hForm hG x
  right_inv := by
    intro x
    exact completedGroupAlgebraToInClass_fromInClass (R := R) (G := G) C hForm hG x
  map_mul' := by
    intro x y
    exact map_mul (completedGroupAlgebraToInClassRingHom (R := R) (G := G) C ) x y
  map_add' := by
    intro x y
    exact map_add (completedGroupAlgebraToInClassRingHom (R := R) (G := G) C ) x y
CompletedGroupAlgebra.completedGroupAlgebraInClassRingEquiv_apply

The comparison equivalence is evaluated by the underlying all-finite or \(C\)-indexed comparison map.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraInClassRingEquiv_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraCarrier R G) :
    completedGroupAlgebraInClassRingEquiv (R := R) (G := G) C hForm hG x =
      completedGroupAlgebraToInClass (R := R) (G := G) C x
CompletedGroupAlgebra.completedGroupAlgebraInClassRingEquiv_symm_apply

The comparison equivalence is evaluated by the underlying all-finite or \(C\)-indexed comparison map.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraInClassRingEquiv_symm_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraInClass C R G) :
    (completedGroupAlgebraInClassRingEquiv (R := R) (G := G) C hForm hG).symm x =
      completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x
CompletedGroupAlgebra.completedGroupAlgebraInClassAlgEquiv

For a pro-\(C\) group, the all-finite and \(C\)-indexed completed group algebras are the same \(R\)-algebra.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraInClassAlgEquiv
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    CompletedGroupAlgebraCarrier R G ≃ₐ[R] CompletedGroupAlgebraInClass C R G
CompletedGroupAlgebra.completedGroupAlgebraInClassAlgEquiv_apply

The comparison equivalence is evaluated by the underlying all-finite or \(C\)-indexed comparison map.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraInClassAlgEquiv_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraCarrier R G) :
    completedGroupAlgebraInClassAlgEquiv (R := R) (G := G) C hForm hG x =
      completedGroupAlgebraToInClass (R := R) (G := G) C x
CompletedGroupAlgebra.completedGroupAlgebraInClassAlgEquiv_symm_apply

The comparison equivalence is evaluated by the underlying all-finite or \(C\)-indexed comparison map.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraInClassAlgEquiv_symm_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraInClass C R G) :
    (completedGroupAlgebraInClassAlgEquiv (R := R) (G := G) C hForm hG).symm x =
      completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x
CompletedGroupAlgebra.completedGroupAlgebraInClassHomeomorph

The comparison equivalence is an equivalence of topological spaces.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
def completedGroupAlgebraInClassHomeomorph
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    CompletedGroupAlgebraCarrier R G ≃ₜ CompletedGroupAlgebraInClass C R G where
  toEquiv := (completedGroupAlgebraInClassRingEquiv (R := R) (G := G) C hForm hG).toEquiv
  continuous_toFun := continuous_completedGroupAlgebraToInClass (R := R) (G := G) C
  continuous_invFun := continuous_completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG
CompletedGroupAlgebra.completedGroupAlgebraInClassHomeomorph_apply

The comparison homeomorphism is evaluated by the underlying all-finite or \(C\)-indexed comparison map.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraInClassHomeomorph_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraCarrier R G) :
    completedGroupAlgebraInClassHomeomorph (R := R) (G := G) C hForm hG x =
      completedGroupAlgebraToInClass (R := R) (G := G) C x
CompletedGroupAlgebra.completedGroupAlgebraInClassHomeomorph_symm_apply

The comparison homeomorphism is evaluated by the underlying all-finite or \(C\)-indexed comparison map.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraInClassHomeomorph_symm_apply
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) (x :
        CompletedGroupAlgebraInClass C R G) :
    (completedGroupAlgebraInClassHomeomorph (R := R) (G := G) C hForm hG).symm x =
      completedGroupAlgebraFromInClass (R := R) (G := G) C hForm hG x
CompletedGroupAlgebra.completedGroupAlgebraToInClass_surjective

Surjectivity of the induced map is obtained from surjectivity on the underlying quotient or dense algebraic model, together with closedness of the image in the completed target.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraToInClass_surjective
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    Function.Surjective (completedGroupAlgebraToInClassRingHom (R := R) (G := G) C )
CompletedGroupAlgebra.completedGroupAlgebraFromInClass_surjective

Surjectivity of the induced map is obtained from surjectivity on the underlying quotient or dense algebraic model, together with closedness of the image in the completed target.

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
open ProCGroups.Completion
universe u v w
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable (R : Type u) [CommRing R] [TopologicalSpace R] [IsTopologicalRing R]
theorem completedGroupAlgebraFromInClass_surjective
    (C : ProCGroups.FiniteGroupClass.{v})
    (hForm : ProCGroups.FiniteGroupClass.Formation C) (hG : HasOpenNormalBasisInClass C G) :
    Function.Surjective (completedGroupAlgebraFromInClassRingHom (R := R) (G := G) C hForm hG)