Module

ModPFilteredExactness.lean

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

Filtered packaging for the mod-p Fox complex

The coordinate module is filtered coordinatewise by closed augmentation powers. A displayed relator of Zassenhaus depth at least ν j gives a row of depth at least ν j - 1; this makes the relation matrix filtered when its source is given the corresponding shifted filtration. The Fox boundary raises coordinate depth by one.

The final theorem packages these filtration bounds with the underlying unfiltered exactness and the identification of the boundary range. It does not assert strictness of either filtered map.

Declarations

ClassFieldTower.ProP.presentationModPFoxCoordinateFiltration

The coordinatewise closed-augmentation filtration on mod-p Fox vectors.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open FoxDifferential
open ProCGroups
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]
def presentationModPFoxCoordinateFiltration (n : ℕ) :
    Submodule (ModPCompletedGroupAlgebra p G)
      (PresentationModPFoxCoordinates (p := p) (d := d) (G := G)) where
  carrier := {v | ∀ i, v i ∈ closedAugmentationPower p G n}
  zero_mem' i := (closedAugmentationPower p G n).zero_mem
  add_mem' {v w} hv hw i :=
    (closedAugmentationPower p G n).add_mem (hv i) (hw i)
  smul_mem' a v hv i := by
    change a * v i ∈ closedAugmentationPower p G n
    exact (closedAugmentationPower p G n).mul_mem_left a (hv i)
ClassFieldTower.ProP.mem_presentationModPFoxCoordinateFiltration_iff

Membership in the coordinate filtration is coordinatewise membership.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open FoxDifferential
open ProCGroups
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]
theorem mem_presentationModPFoxCoordinateFiltration_iff
    (n : ℕ)
    (v : PresentationModPFoxCoordinates (p := p) (d := d) (G := G)) :
    v ∈ presentationModPFoxCoordinateFiltration (p := p) (d := d) (G := G) n ↔
      ∀ i, v i ∈ closedAugmentationPower p G n
ClassFieldTower.ProP.presentationModPWeightedRelationSourceFiltration

The source filtration shifted by the prescribed Zassenhaus depth ν of each displayed relator.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open FoxDifferential
open ProCGroups
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]
def presentationModPWeightedRelationSourceFiltration
    (ν : Fin r → ℕ) (N : ℕ) :
    Submodule (ModPCompletedGroupAlgebra p G)
      (Fin r → ModPCompletedGroupAlgebra p G) where
  carrier := {a | ∀ j, a j ∈ closedAugmentationPower p G (N + 1 - ν j)}
  zero_mem' j := (closedAugmentationPower p G (N + 1 - ν j)).zero_mem
  add_mem' {a b} ha hb j :=
    (closedAugmentationPower p G (N + 1 - ν j)).add_mem (ha j) (hb j)
  smul_mem' c a ha j := by
    change c * a j ∈ closedAugmentationPower p G (N + 1 - ν j)
    exact (closedAugmentationPower p G (N + 1 - ν j)).mul_mem_left c (ha j)
ClassFieldTower.ProP.mem_presentationModPWeightedRelationSourceFiltration_iff

Membership in the weighted source filtration is the stated shifted coordinatewise condition.

Source context 10 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open FoxDifferential
open ProCGroups
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]
theorem mem_presentationModPWeightedRelationSourceFiltration_iff
    (ν : Fin r → ℕ) (N : ℕ)
    (a : Fin r → ModPCompletedGroupAlgebra p G) :
    a ∈ presentationModPWeightedRelationSourceFiltration
        (p := p) (G := G) ν N ↔
      ∀ j, a j ∈ closedAugmentationPower p G (N + 1 - ν j)
ClassFieldTower.ProP.presentationModPFoxBoundary_mem_closedAugmentationPower_succ

The mod-p Fox boundary sends coordinate depth n to augmentation depth n + 1.

Source context 11 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open FoxDifferential
open ProCGroups
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 presentationModPFoxBoundary_mem_closedAugmentationPower_succ
    (P : FiniteProPPresentation p d r sourceData G) (n : ℕ)
    {v : PresentationModPFoxCoordinates (p := p) (d := d) (G := G)}
    (hv : v ∈ presentationModPFoxCoordinateFiltration
      (p := p) (d := d) (G := G) n) :
    presentationModPFoxBoundary P v ∈ closedAugmentationPower p G (n + 1)
ClassFieldTower.ProP.presentationModPRelationMatrix_mem_coordinateFiltration

With the source shifted by the displayed-relator depths, the relation matrix preserves every target filtration depth.

Source context 11 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open FoxDifferential
open ProCGroups
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_mem_coordinateFiltration
    (P : FiniteProPPresentation p d r sourceData G)
    (ν : Fin r → ℕ)
    (hν : ∀ j, P.RelatorZassenhausDepthAtLeast (ν j) j)
    (N : ℕ) {a : Fin r → ModPCompletedGroupAlgebra p G}
    (ha : a ∈ presentationModPWeightedRelationSourceFiltration
      (p := p) (G := G) ν N) :
    presentationModPRelationMatrix P a ∈
      presentationModPFoxCoordinateFiltration
        (p := p) (d := d) (G := G) N
ClassFieldTower.ProP.presentationModP_filteredRelationBoundary_package

The filtered bounds together with the underlying exactness and the augmentation-ideal description of the boundary range. This package makes no strict filtered-lifting claim.

Source context 11 commands

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

open scoped Topology
namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open FoxDifferential
open ProCGroups
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 presentationModP_filteredRelationBoundary_package
    (P : FiniteProPPresentation p d r sourceData G)
    (ν : Fin r → ℕ)
    (hν : ∀ j, P.RelatorZassenhausDepthAtLeast (ν j) j) :
    Function.Exact (presentationModPRelationMatrix P)
        (presentationModPFoxBoundary P) ∧
      LinearMap.range (presentationModPFoxBoundary P) =
        (modPAugmentationIdeal p G :
          Submodule (ModPCompletedGroupAlgebra p G)
            (ModPCompletedGroupAlgebra p G)) ∧
      (∀ (n : ℕ)
          {v : PresentationModPFoxCoordinates (p := p) (d := d) (G := G)},
        v ∈ presentationModPFoxCoordinateFiltration
            (p := p) (d := d) (G := G) n →
          presentationModPFoxBoundary P v ∈
            closedAugmentationPower p G (n + 1)) ∧
      ∀ (N : ℕ) {a : Fin r → ModPCompletedGroupAlgebra p G},
        a ∈ presentationModPWeightedRelationSourceFiltration
            (p := p) (G := G) ν N →
          presentationModPRelationMatrix P a ∈
            presentationModPFoxCoordinateFiltration
              (p := p) (d := d) (G := G) N