Module

ClosedSpan.lean

Nyll.ProCGroups.ProP.Fox.ClosedSpan
5 declarations indexed from sourceView source ↗

Closed generation of completed kernel Fox rows

Continuity and crossed-product identities turn the inverse image of the displayed-row span into a closed normal subgroup. Since the displayed relators closed-normally generate the kernel, every kernel row lies in their closed coefficient span.

Declarations

ClassFieldTower.ProP.kernelRowsInDisplayedClosedSpan

Kernel elements whose completed Fox rows lie in the displayed closed span.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open ProCGroups
open FoxDifferential
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 kernelRowsInDisplayedClosedSpan
    (P : FiniteProPPresentation p d r sourceData G) :
    Subgroup sourceData.carrier where
  carrier := {x |
    x ∈ P.quotient.toMonoidHom.ker ∧
      presentationFoxDerivative P x ∈ displayedRelatorFoxRowClosedSpan P}
  one_mem' := by
    constructor
    · simp
    · rw [ScalarCrossedHom.map_one]
      exact (displayedRelatorFoxRowClosedSpan P).zero_mem
  mul_mem' := by
    intro x y hx hy
    constructor
    · exact P.quotient.toMonoidHom.ker.mul_mem hx.1 hy.1
    · rw [ScalarCrossedHom.map_mul]
      exact (displayedRelatorFoxRowClosedSpan P).add_mem hx.2
        ((displayedRelatorFoxRowClosedSpan P).smul_mem _ hy.2)
  inv_mem' := by
    intro x hx
    constructor
    · exact P.quotient.toMonoidHom.ker.inv_mem hx.1
    · rw [ScalarCrossedHom.map_inv]
      exact (displayedRelatorFoxRowClosedSpan P).neg_mem
        ((displayedRelatorFoxRowClosedSpan P).smul_mem _ hx.2)
ClassFieldTower.ProP.kernelRowsInDisplayedClosedSpan_normal

The row-controlled kernel subgroup is normal in the free source.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open ProCGroups
open FoxDifferential
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 kernelRowsInDisplayedClosedSpan_normal
    (P : FiniteProPPresentation p d r sourceData G) :
    (kernelRowsInDisplayedClosedSpan P).Normal where
  conj_mem n hn g := by
    rcases hn with ⟨hnker, hnrow⟩
    constructor
    · change P.quotient (g * n * g⁻¹) = 1
      change P.quotient n = 1 at hnker
      simp [hnker]
    · rw [ScalarCrossedHom.map_conj]
      change P.quotient n = 1 at hnker
      have hcoeff :
          zcCompletedGroupAlgebraScalar
              (FiniteGroupClass.pGroup p) P.quotient.toMonoidHom
              (g * n * g⁻¹) = 1 := by
        simp [hnker]
      rw [hcoeff, one_smul]
      simpa only [add_sub_cancel_left] using
        (displayedRelatorFoxRowClosedSpan P).smul_mem
          (zcCompletedGroupAlgebraScalar
            (FiniteGroupClass.pGroup p) P.quotient.toMonoidHom g)
          hnrow
ClassFieldTower.ProP.isClosed_kernelRowsInDisplayedClosedSpan

The row-controlled kernel subgroup is topologically closed.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open ProCGroups
open FoxDifferential
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_kernelRowsInDisplayedClosedSpan
    (P : FiniteProPPresentation p d r sourceData G) :
    IsClosed ((kernelRowsInDisplayedClosedSpan P : Subgroup sourceData.carrier) :
      Set sourceData.carrier)
ClassFieldTower.ProP.displayedRelators_subset_kernelRowsInDisplayedClosedSpan

Every displayed relator belongs to the row-controlled kernel subgroup.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open ProCGroups
open FoxDifferential
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 displayedRelators_subset_kernelRowsInDisplayedClosedSpan
    (P : FiniteProPPresentation p d r sourceData G) :
    Set.range P.relator ⊆ kernelRowsInDisplayedClosedSpan P
ClassFieldTower.ProP.kernelFoxRow_mem_displayedRelatorFoxRowClosedSpan

Every completed kernel row belongs to the closed coefficient span of the displayed finite row family.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open ProCGroups
open FoxDifferential
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 kernelFoxRow_mem_displayedRelatorFoxRowClosedSpan
    (P : FiniteProPPresentation p d r sourceData G)
    (x : P.quotient.toMonoidHom.ker) :
    kernelFoxRow P x ∈ displayedRelatorFoxRowClosedSpan P