Module

Topology.lean

Nyll.ProCGroups.CompletedGroupAlgebra.OpenFiniteQuotientTopology.OpenFiniteLimit.Topology
8 declarations indexed from sourceView source ↗

Completed Group Algebra / Open Finite Quotient Topology / Open Finite Limit / Topology

This module transports the discrete topological-ring structures of the open-finite quotient stages through the single two-parameter inverse limit, and records compactness and separation results.

Declarations

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
variable (R : Type u) [CommRing R] [TopologicalSpace R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
instance (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Ring ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K)
CompletedGroupAlgebra.completedGroupAlgebraOpenFiniteQuotientStage_isTopologicalRing

Each two-parameter finite quotient stage is a topological ring for its discrete topology.

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
variable (R : Type u) [CommRing R] [TopologicalSpace R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
local instance (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Ring ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K) := by
  change Ring (CompletedGroupAlgebraOpenQuotientStage R G K)
  infer_instance
theorem completedGroupAlgebraOpenFiniteQuotientStage_isTopologicalRing
    (R : Type u) (G : Type v) [CommRing R] [TopologicalSpace R] [Group G]
    [TopologicalSpace G] [IsTopologicalGroup G]
    (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    letI : TopologicalSpace (CompletedGroupAlgebraOpenQuotientStage R G K) :=
      completedGroupAlgebraOpenFiniteQuotientStageTopology R G K
    IsTopologicalRing (CompletedGroupAlgebraOpenQuotientStage R G K) := by
  let : TopologicalSpace (CompletedGroupAlgebraOpenQuotientStage R G K) :=
    completedGroupAlgebraOpenFiniteQuotientStageTopology R G K
  have : DiscreteTopology (CompletedGroupAlgebraOpenQuotientStage R G K) :=
    completedGroupAlgebraOpenFiniteQuotientStage_discrete R G K
  infer_instance
CompletedGroupAlgebra.completedGroupAlgebraOpenFiniteQuotientStage_fintype

Each open-finite quotient stage is finite for compact topological coefficients.

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
variable (R : Type u) [CommRing R] [TopologicalSpace R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
local instance (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Ring ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K) := by
  change Ring (CompletedGroupAlgebraOpenQuotientStage R G K)
  infer_instance
theorem completedGroupAlgebraOpenFiniteQuotientStage_fintype
    (R : Type u) (G : Type v) [CommRing R] [TopologicalSpace R] [Group G]
    [TopologicalSpace G] [IsTopologicalGroup G] [IsTopologicalRing R] [CompactSpace R]
    (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Nonempty (Fintype (CompletedGroupAlgebraOpenQuotientStage R G K))
CompletedGroupAlgebra.instIsTopologicalRingCompletedGroupAlgebraOpenFiniteQuotientSystemX

Each open-finite quotient stage has its discrete topological-ring structure.

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
variable (R : Type u) [CommRing R] [TopologicalSpace R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
local instance (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Ring ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K) := by
  change Ring (CompletedGroupAlgebraOpenQuotientStage R G K)
  infer_instance
instance instIsTopologicalRingCompletedGroupAlgebraOpenFiniteQuotientSystemX
    (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    IsTopologicalRing
      ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K)
CompletedGroupAlgebra.instIsTopologicalRingCompletedGroupAlgebraOpenFiniteQuotientLimit

The open-finite quotient limit inherits its topological-ring structure from the generic ring-valued inverse limit.

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
variable (R : Type u) [CommRing R] [TopologicalSpace R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
local instance (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Ring ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K) := by
  change Ring (CompletedGroupAlgebraOpenQuotientStage R G K)
  infer_instance
instance instIsTopologicalRingCompletedGroupAlgebraOpenFiniteQuotientLimit :
    IsTopologicalRing (CompletedGroupAlgebraOpenFiniteQuotientLimit R G)
CompletedGroupAlgebra.completedGroupAlgebraOpenFiniteQuotientLimit_compactSpace

The open-finite quotient limit is compact for compact topological coefficients.

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
variable (R : Type u) [CommRing R] [TopologicalSpace R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
local instance (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Ring ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K) := by
  change Ring (CompletedGroupAlgebraOpenQuotientStage R G K)
  infer_instance
theorem completedGroupAlgebraOpenFiniteQuotientLimit_compactSpace
    [IsTopologicalRing R] [CompactSpace R] :
    CompactSpace (CompletedGroupAlgebraOpenFiniteQuotientLimit R G)
CompletedGroupAlgebra.completedGroupAlgebraOpenFiniteQuotientLimit_t2Space

The open-finite quotient limit is Hausdorff.

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
variable (R : Type u) [CommRing R] [TopologicalSpace R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
local instance (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Ring ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K) := by
  change Ring (CompletedGroupAlgebraOpenQuotientStage R G K)
  infer_instance
theorem completedGroupAlgebraOpenFiniteQuotientLimit_t2Space :
    T2Space (CompletedGroupAlgebraOpenFiniteQuotientLimit R G)
CompletedGroupAlgebra.completedGroupAlgebraOpenFiniteQuotientLimit_totallyDisconnectedSpace

The open-finite quotient limit is totally disconnected.

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
variable (R : Type u) [CommRing R] [TopologicalSpace R]
variable (G : Type v) [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
local instance (K : CompletedGroupAlgebraOpenQuotientIndex R G) :
    Ring ((completedGroupAlgebraOpenFiniteQuotientSystem R G).X K) := by
  change Ring (CompletedGroupAlgebraOpenQuotientStage R G K)
  infer_instance
theorem completedGroupAlgebraOpenFiniteQuotientLimit_totallyDisconnectedSpace :
    TotallyDisconnectedSpace (CompletedGroupAlgebraOpenFiniteQuotientLimit R G)