Module

ResidualUniversalProperty.lean

Nyll.ProCGroups.ProC.MaximalQuotients.ResidualUniversalProperty
2 declarations indexed from sourceView source ↗

The canonical residual quotient is maximal pro-C

The actual residual quotient has the required pro-C basis. Every continuous map to a pro-C group factors through its residual core, and surjectivity of the quotient projection gives uniqueness of this factorization.

Declarations

ProCGroups.ProC.residualQuotient_totallyDisconnectedSpace
Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

namespace ProCGroups.ProC
universe u
attribute [local instance] proCResidualCore_isClosed
theorem residualQuotient_totallyDisconnectedSpace
    {C : FiniteGroupClass.{u}}
    {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
    [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G] :
    TotallyDisconnectedSpace (G ⧸ proCResidualCore C G)
ProCGroups.ProC.isMaximalProCQuotient_residualCore

The canonical residual-core projection satisfies the maximal pro-C universal property. The quotient's separation properties are supplied from closedness of the actual core, rather than assumed.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

namespace ProCGroups.ProC
universe u
attribute [local instance] proCResidualCore_isClosed
attribute [local instance] residualQuotient_totallyDisconnectedSpace
theorem isMaximalProCQuotient_residualCore
    {C : FiniteGroupClass.{u}}
    {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
    [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
    (hForm : FiniteGroupClass.Formation C) (hHer : FiniteGroupClass.Hereditary C) :
    IsMaximalProCQuotient C (QuotientGroup.mk' (proCResidualCore C G))