Module

FinitePresentationExistence.lean

Nyll.GaloisCohomology.ProP.FinitePresentationExistence
1 declaration indexed from sourceView source ↗

Constructing finite minimal pro-p presentations

A finitely generated pro-p group with finite-dimensional H² has an actual finite minimal presentation. The free source is constructed by completion, its epimorphism is minimal by equality of generator ranks, and the closed kernel is normally generated using H².

Imports39
Imported by3

Declarations

ClassFieldTower.ProP.hasFiniteMinimalPresentation_of_finiteDimensional_h2

Finite generation and finite-dimensional H² supply an actual finite minimal pro-p presentation, including the free source, quotient map, and finite relator family.

Source context 6 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open ProCGroups ProCGroups.FreeProC ProCGroups.Generation ProCGroups.FiniteGeneration
open ProCGroups.Presentations ClassFieldTower.Cohomology
noncomputable section
universe u
theorem hasFiniteMinimalPresentation_of_finiteDimensional_h2
    {p : ℕ} [Fact p.Prime]
    {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
    [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
    (hG : ProC.HasPGroupOpenNormalBasis p G)
    (hfg : TopologicallyFinitelyGenerated G)
    [FiniteDimensional (ZMod p) (continuousCohomologyZModPLifted p G 2)] :
    HasFiniteMinimalPresentation p G