Module

GradedPieces.lean

Nyll.ProCGroups.GolodShafarevich.GradedPieces
8 declarations indexed from sourceView source ↗

Truncated augmentation dimensions

This file packages the finite-dimensional quotients of a mod-p completed group algebra used by the truncated Golod--Shafarevich inequality. The shifted definition uses truncated subtraction, so shifts beyond the cutoff give the zero quotient without side conditions in downstream statements.

Declarations

ClassFieldTower.ProP.finite_modPCompletedGroupAlgebra

For a finite profinite group, its mod-p completed group algebra is a finite type. This is kept as a theorem so no noncanonical global instance is installed.

Source context 9 commands

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

namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open ProCGroups
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
omit [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G] in
theorem finite_modPCompletedGroupAlgebra [Finite G] :
    Finite (ModPCompletedGroupAlgebra p G)
ClassFieldTower.ProP.shiftedClosedAugmentationSubmodule

The subspace killed at cutoff N after a filtration shift shift.

Source context 8 commands

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

namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open ProCGroups
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
def shiftedClosedAugmentationSubmodule (N shift : ℕ) :
    Submodule (ZMod p) (ModPCompletedGroupAlgebra p G)
ClassFieldTower.ProP.ShiftedAugmentationTruncation

The completed group algebra truncated at N, with filtration shift shift.

Source context 8 commands

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

namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open ProCGroups
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
abbrev ShiftedAugmentationTruncation (N shift : ℕ)
ClassFieldTower.ProP.truncatedAugmentationDimension

Dimension of the unshifted truncation Λ / I^(N+1).

Source context 8 commands

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

namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open ProCGroups
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
def truncatedAugmentationDimension (N : ℕ) : ℕ
ClassFieldTower.ProP.shiftedTruncatedAugmentationDimension

Dimension of the truncation after an arbitrary filtration shift.

Source context 8 commands

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

namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open ProCGroups
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
def shiftedTruncatedAugmentationDimension (N shift : ℕ) : ℕ
ClassFieldTower.ProP.truncatedAugmentationDimensionStar

Nat-safe shifted dimension: A (N-shift) inside the cutoff and zero outside it.

Source context 8 commands

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

namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open ProCGroups
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
def truncatedAugmentationDimensionStar (N shift : ℕ) : ℕ
ClassFieldTower.ProP.closedAugmentationPower_zero_eq_top
Source context 9 commands

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

namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open ProCGroups
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
omit [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G] in
theorem closedAugmentationPower_zero_eq_top :
    closedAugmentationPower p G 0 = ⊤
ClassFieldTower.ProP.shiftedTruncatedAugmentationDimension_eq_star

The quotient definition of a shifted dimension agrees with its Nat-safe piecewise form.

Source context 9 commands

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

namespace ClassFieldTower.ProP
open CompletedGroupAlgebra
open ProCGroups
noncomputable section
universe u
variable {p : ℕ} [Fact p.Prime]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
omit [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G] in
theorem shiftedTruncatedAugmentationDimension_eq_star (N shift : ℕ) :
    shiftedTruncatedAugmentationDimension (p := p) (G := G) N shift =
      truncatedAugmentationDimensionStar (p := p) (G := G) N shift