Module

ModPDensityExactness.lean

Nyll.ProCGroups.ProP.Fox.ModPDensityExactness
7 declarations indexed from sourceView source ↗

Completed mod-p Fox density and relation exactness

Finite reflected Fox exactness supplies a matching presentation word at every finite p-group quotient. The corresponding matching subsets of the compact free pro-p source are nonempty, closed, and directed under refinement. Compactness therefore produces one source element matching all completed coefficient coordinates and all target quotients. Separation identifies it as an actual presentation-kernel element whose mod-p Fox derivative is the given boundary cycle.

Combining this density result with the displayed-row span theorem proves unfiltered exactness of the completed relation matrix followed by the Fox boundary.

Declarations

ClassFieldTower.ProP.presentationModPFiniteStageRightMap_presentationWord

The reflected right projection sends a presentation word to its finite quotient class.

Source context 13 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open CrowellExactSequence
open FoxDifferential
open ProCGroups
open ProCGroups.ProC
noncomputable section
universe u
variable {p d r : ℕ} [Fact p.Prime]
variable {sourceData :
  FreeProC.EpimorphicallyFreeProCGroupOnConvergingSetData.{u, u}
    (FiniteGroupClass.pGroup p)}
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
theorem presentationModPFiniteStageRightMap_presentationWord
    (P : FiniteProPPresentation p d r sourceData G)
    (U : OpenNormalSubgroup G)
    (hU : FiniteGroupClass.pGroup p (G ⧸ (U : Subgroup G)))
    (w : FreeGroup (ULift.{u} (Fin d))) :
    presentationModPFiniteStageRightMap P U hU
        (P.quotient (FreeGroup.lift (presentationChosenGenerator P) w)) =
      QuotientGroup.mk' (presentationModPFiniteStageKernel P U hU) w
ClassFieldTower.ProP.presentationModPFiniteStageMatchSet

Raw finite-stage equality conditions on a possible lift of a completed boundary cycle.

Source context 13 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open CrowellExactSequence
open FoxDifferential
open ProCGroups
open ProCGroups.ProC
noncomputable section
universe u
variable {p d r : ℕ} [Fact p.Prime]
variable {sourceData :
  FreeProC.EpimorphicallyFreeProCGroupOnConvergingSetData.{u, u}
    (FiniteGroupClass.pGroup p)}
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
def presentationModPFiniteStageMatchSet
    (P : FiniteProPPresentation p d r sourceData G)
    (v : PresentationModPFoxCoordinates (p := p) (d := d) (G := G))
    (j : CompletedGroupAlgebra.CompletedGroupAlgebraIndexInClass G
      (FiniteGroupClass.pGroup p)) :
    Set sourceData.carrier
ClassFieldTower.ProP.presentationModPFiniteStageMatchSet_nonempty

Finite-stage exactness produces a presentation word matching a completed boundary cycle at every raw coefficient and target quotient coordinate.

Source context 13 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open CrowellExactSequence
open FoxDifferential
open ProCGroups
open ProCGroups.ProC
noncomputable section
universe u
variable {p d r : ℕ} [Fact p.Prime]
variable {sourceData :
  FreeProC.EpimorphicallyFreeProCGroupOnConvergingSetData.{u, u}
    (FiniteGroupClass.pGroup p)}
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
theorem presentationModPFiniteStageMatchSet_nonempty
    (P : FiniteProPPresentation p d r sourceData G)
    (v : PresentationModPFoxCoordinates (p := p) (d := d) (G := G))
    (hv : presentationModPFoxBoundary P v = 0)
    (j : CompletedGroupAlgebra.CompletedGroupAlgebraIndexInClass G
      (FiniteGroupClass.pGroup p)) :
    (presentationModPFiniteStageMatchSet P v j).Nonempty
ClassFieldTower.ProP.isClosed_presentationModPFiniteStageMatchSet

Each raw finite-stage matching condition is closed in the compact free pro-p source.

Source context 13 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open CrowellExactSequence
open FoxDifferential
open ProCGroups
open ProCGroups.ProC
noncomputable section
universe u
variable {p d r : ℕ} [Fact p.Prime]
variable {sourceData :
  FreeProC.EpimorphicallyFreeProCGroupOnConvergingSetData.{u, u}
    (FiniteGroupClass.pGroup p)}
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
theorem isClosed_presentationModPFiniteStageMatchSet
    (P : FiniteProPPresentation p d r sourceData G)
    (v : PresentationModPFoxCoordinates (p := p) (d := d) (G := G))
    (j : CompletedGroupAlgebra.CompletedGroupAlgebraIndexInClass G
      (FiniteGroupClass.pGroup p)) :
    IsClosed (presentationModPFiniteStageMatchSet P v j)
ClassFieldTower.ProP.presentationModPFiniteStageMatchSet_anti

Matching at a finer raw quotient stage implies matching at every coarser stage.

Source context 13 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open CrowellExactSequence
open FoxDifferential
open ProCGroups
open ProCGroups.ProC
noncomputable section
universe u
variable {p d r : ℕ} [Fact p.Prime]
variable {sourceData :
  FreeProC.EpimorphicallyFreeProCGroupOnConvergingSetData.{u, u}
    (FiniteGroupClass.pGroup p)}
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
theorem presentationModPFiniteStageMatchSet_anti
    (P : FiniteProPPresentation p d r sourceData G)
    (v : PresentationModPFoxCoordinates (p := p) (d := d) (G := G))
    {j k : CompletedGroupAlgebra.CompletedGroupAlgebraIndexInClass G
      (FiniteGroupClass.pGroup p)} (hjk : j ≤ k) :
    presentationModPFiniteStageMatchSet P v k ⊆
      presentationModPFiniteStageMatchSet P v j
ClassFieldTower.ProP.exists_presentationKernel_of_presentationModPFoxBoundary_eq_zero

Every completed mod-p boundary cycle is the Fox derivative of an actual presentation-kernel element.

Source context 13 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open CrowellExactSequence
open FoxDifferential
open ProCGroups
open ProCGroups.ProC
noncomputable section
universe u
variable {p d r : ℕ} [Fact p.Prime]
variable {sourceData :
  FreeProC.EpimorphicallyFreeProCGroupOnConvergingSetData.{u, u}
    (FiniteGroupClass.pGroup p)}
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
theorem exists_presentationKernel_of_presentationModPFoxBoundary_eq_zero
    (P : FiniteProPPresentation p d r sourceData G)
    (v : PresentationModPFoxCoordinates (p := p) (d := d) (G := G))
    (hv : presentationModPFoxBoundary P v = 0) :
    ∃ f : sourceData.carrier,
      P.quotient f = 1 ∧ presentationModPFoxDerivative P f = v
ClassFieldTower.ProP.presentationModPRelationMatrix_boundary_exact

Unfiltered exactness of the completed relation matrix followed by the mod-p Fox boundary.

Source context 13 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open CrowellExactSequence
open FoxDifferential
open ProCGroups
open ProCGroups.ProC
noncomputable section
universe u
variable {p d r : ℕ} [Fact p.Prime]
variable {sourceData :
  FreeProC.EpimorphicallyFreeProCGroupOnConvergingSetData.{u, u}
    (FiniteGroupClass.pGroup p)}
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
theorem presentationModPRelationMatrix_boundary_exact
    (P : FiniteProPPresentation p d r sourceData G) :
    Function.Exact (presentationModPRelationMatrix P)
      (presentationModPFoxBoundary P)