Module

Augmentation.lean

Nyll.ProCGroups.FoxDifferential.Completed.ProCIntegerCoefficients.Augmentation
17 declarations indexed from sourceView source ↗

Fox differential: completed — \(\mathbb{Z}_C\) coefficients — augmentation

The principal declarations in this module are:

  • zcCompletedGroupAlgebraTopIndex

The canonical trivial group quotient used to read the completed augmentation.

  • zcCompletedGroupAlgebraAugmentationFamily

The finite coefficient coordinate of the completed augmentation \(\mathbb{Z}_C\llbracket H\rrbracket \to \mathbb{Z}_C\).

  • zcCompletedGroupAlgebraTopIndex_le

The canonical trivial quotient is below every finite quotient index.

  • zcCompletedGroupAlgebraAugmentationFamily_compatible

The finite coefficient coordinates of the completed augmentation are compatible.

Declarations

FoxDifferential.zcCompletedGroupAlgebraTopIndex

The canonical trivial group quotient used to read the completed augmentation.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
abbrev zcCompletedGroupAlgebraTopIndex : CompletedGroupAlgebraIndexInClass H C
FoxDifferential.zcCompletedGroupAlgebraTopIndex_le

The canonical trivial quotient is below every finite quotient index.

Source context 10 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
omit [IsTopologicalGroup H] in
theorem zcCompletedGroupAlgebraTopIndex_le
    (U : CompletedGroupAlgebraIndexInClass H C) :
    zcCompletedGroupAlgebraTopIndex C H ≤ U
FoxDifferential.zcCompletedGroupAlgebraAugmentationFamily

The finite coefficient coordinate of the completed augmentation \(\mathbb{Z}_C\llbracket H\rrbracket \to \mathbb{Z}_C\).

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
def zcCompletedGroupAlgebraAugmentationFamily
    (x : ZCCompletedGroupAlgebra C H) (i : ProCIntegerIndex C) :
    ProCIntegerStage C i
FoxDifferential.zcCompletedGroupAlgebraAugmentationFamily_compatible

The finite coefficient coordinates of the completed augmentation are compatible.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem zcCompletedGroupAlgebraAugmentationFamily_compatible
    (x : ZCCompletedGroupAlgebra C H) {i j : ProCIntegerIndex C} (hij : i ≤ j) :
    proCIntegerTransition (C := C) hij
        (zcCompletedGroupAlgebraAugmentationFamily C H x j) =
      zcCompletedGroupAlgebraAugmentationFamily C H x i
FoxDifferential.zcCompletedGroupAlgebraAugmentation

The completed augmentation \(\mathbb{Z}_C\llbracket H\rrbracket \to \mathbb{Z}_C\), obtained by augmenting every finite stage \((\mathbb{Z}/n\mathbb{Z})[H/U]\) at the canonical trivial quotient of \(H\).

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
def zcCompletedGroupAlgebraAugmentation :
    ZCCompletedGroupAlgebra C H →+* ZCCoeff C where
  toFun x :=
    Subtype.mk
      (zcCompletedGroupAlgebraAugmentationFamily C H x)
      (by
        intro i j hij
        exact zcCompletedGroupAlgebraAugmentationFamily_compatible C H x hij)
  map_zero' := by
    ext i
    change zcCompletedGroupAlgebraAugmentationFamily C H
        (0 : ZCCompletedGroupAlgebra C H) i = 0
    simp only [zcCompletedGroupAlgebraAugmentationFamily,
        zcCompletedGroupAlgebraProjection_zero, map_zero]
  map_one' := by
    ext i
    change zcCompletedGroupAlgebraAugmentationFamily C H
        (1 : ZCCompletedGroupAlgebra C H) i = 1
    simp only [zcCompletedGroupAlgebraAugmentationFamily, zcCompletedGroupAlgebraProjection_one,
        map_one]
  map_add' x y := by
    ext i
    change zcCompletedGroupAlgebraAugmentationFamily C H (x + y) i =
      zcCompletedGroupAlgebraAugmentationFamily C H x i +
        zcCompletedGroupAlgebraAugmentationFamily C H y i
    simp only [zcCompletedGroupAlgebraAugmentationFamily, zcCompletedGroupAlgebraProjection_add,
        map_add]
  map_mul' x y := by
    ext i
    change zcCompletedGroupAlgebraAugmentationFamily C H (x * y) i =
      zcCompletedGroupAlgebraAugmentationFamily C H x i *
        zcCompletedGroupAlgebraAugmentationFamily C H y i
    simp only [zcCompletedGroupAlgebraAugmentationFamily, zcCompletedGroupAlgebraProjection_mul,
        map_mul]
FoxDifferential.proCIntegerProj_zcCompletedGroupAlgebraAugmentation

Projecting the completed augmentation gives the corresponding finite-stage augmentation.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem proCIntegerProj_zcCompletedGroupAlgebraAugmentation
    (i : ProCIntegerIndex C) (x : ZCCompletedGroupAlgebra C H) :
    proCIntegerProj (C := C) i (zcCompletedGroupAlgebraAugmentation C H x) =
      zcCompletedGroupAlgebraAugmentationFamily C H x i
FoxDifferential.proCIntegerProj_zcCompletedGroupAlgebraAugmentation_eq_stage

The completed augmentation can be read after projecting to any finite group quotient stage, not only the canonical trivial quotient used in its definition.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem proCIntegerProj_zcCompletedGroupAlgebraAugmentation_eq_stage
    (i : ZCCompletedGroupAlgebraIndex C H) (x : ZCCompletedGroupAlgebra C H) :
    proCIntegerProj (C := C) i.1 (zcCompletedGroupAlgebraAugmentation C H x) =
      modNCompletedGroupAlgebraStageAugmentationInClass i.1.modulus H C i.2
        (zcCompletedGroupAlgebraProjection C H i x)
FoxDifferential.zcCompletedGroupAlgebraAugmentation_groupLike

The completed augmentation sends every group-like element to \(1\).

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem zcCompletedGroupAlgebraAugmentation_groupLike (h : H) :
    zcCompletedGroupAlgebraAugmentation C H (zcGroupLike C H h) = 1
FoxDifferential.zcCompletedGroupAlgebraAugmentation_boundary

The completed Fox boundary has augmentation zero.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem zcCompletedGroupAlgebraAugmentation_boundary
    {G : Type u} [Group G] (ψ : G →* H) (g : G) :
    zcCompletedGroupAlgebraAugmentation C H
        (zcCompletedGroupAlgebraBoundary C ψ g) = 0
FoxDifferential.zcCompletedGroupAlgebraAugmentationIdeal

The completed augmentation ideal, defined as the kernel of \(\mathbb{Z}_C\llbracket H\rrbracket \to \mathbb{Z}_C\).

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
def zcCompletedGroupAlgebraAugmentationIdeal :
    Ideal (ZCCompletedGroupAlgebra C H)
FoxDifferential.ZCCompletedGroupAlgebraAugmentationIdeal

The completed augmentation ideal is bundled as a subtype.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
abbrev ZCCompletedGroupAlgebraAugmentationIdeal : Type u
FoxDifferential.mem_zcCompletedGroupAlgebraAugmentationIdeal_iff

A completed integer group-algebra element lies in the completed augmentation ideal iff the completed augmentation sends it to zero.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem mem_zcCompletedGroupAlgebraAugmentationIdeal_iff
    {C : ProCGroups.FiniteGroupClass.{u}}
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
    {H : Type u} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
    {x : ZCCompletedGroupAlgebra C H} :
    x ∈ zcCompletedGroupAlgebraAugmentationIdeal C H ↔
      zcCompletedGroupAlgebraAugmentation C H x = 0
FoxDifferential.zcCompletedGroupAlgebraStandardAugmentationIdeal_le_augmentationIdeal

The algebraic standard-generator ideal is contained in the completed augmentation ideal.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem zcCompletedGroupAlgebraStandardAugmentationIdeal_le_augmentationIdeal :
    zcCompletedGroupAlgebraStandardAugmentationIdeal C H ≤
      zcCompletedGroupAlgebraAugmentationIdeal C H
FoxDifferential.zcCompletedGroupAlgebraBoundary_mem_augmentationIdeal

The completed Fox boundary lies in the completed augmentation ideal.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem zcCompletedGroupAlgebraBoundary_mem_augmentationIdeal
    {G : Type u} [Group G] (ψ : G →* H) (g : G) :
    zcCompletedGroupAlgebraBoundary C ψ g ∈
      zcCompletedGroupAlgebraAugmentationIdeal C H
FoxDifferential.exact_zcToCompletedGA_of_surj_of_standardAugmentationIdeal_eq_augmentationIdeal

If the completed augmentation kernel is the algebraic standard-generator ideal, then a surjective completed Fox boundary gives exactness at \(\mathbb{Z}_C\llbracket H\rrbracket\).

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem exact_zcToCompletedGA_of_surj_of_standardAugmentationIdeal_eq_augmentationIdeal
    {G : Type u} [Group G] (ψ : G →* H) (hψ : Function.Surjective ψ)
    (hstandard :
      zcCompletedGroupAlgebraStandardAugmentationIdeal C H =
        zcCompletedGroupAlgebraAugmentationIdeal C H) :
    Function.Exact
      (zcToCompletedGroupAlgebra C ψ :
        ZCCompletedDifferentialModule C ψ → ZCCompletedGroupAlgebra C H)
      (zcCompletedGroupAlgebraAugmentation C H :
        ZCCompletedGroupAlgebra C H → ZCCoeff C)
FoxDifferential.exact_zcToCompletedGA_iff_standardAugmentationIdeal_eq_augmentationIdeal_of_surj

For a surjective coefficient group map, exactness of the algebraic completed Fox tail is equivalent to the algebraic standard-generator ideal already being the completed augmentation ideal. This isolates the closed-range obstruction for infinite completed group algebras.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem exact_zcToCompletedGA_iff_standardAugmentationIdeal_eq_augmentationIdeal_of_surj
    {C : ProCGroups.FiniteGroupClass.{u}}
    [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
    {H : Type u} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
    {G : Type u} [Group G] (ψ : G →* H) (hψ : Function.Surjective ψ) :
    Function.Exact
        (zcToCompletedGroupAlgebra C ψ :
          ZCCompletedDifferentialModule C ψ → ZCCompletedGroupAlgebra C H)
        (zcCompletedGroupAlgebraAugmentation C H :
          ZCCompletedGroupAlgebra C H → ZCCoeff C) ↔
      zcCompletedGroupAlgebraStandardAugmentationIdeal C H =
        zcCompletedGroupAlgebraAugmentationIdeal C H
FoxDifferential.zcCompletedGroupAlgebraAugmentation_surjective

The completed augmentation \(\mathbb{Z}_C\llbracket H\rrbracket \to \mathbb{Z}_C\) is surjective.

Source context 9 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.Completion
open ProCGroups.ProC
universe u
section Augmentation
variable (C : ProCGroups.FiniteGroupClass.{u})
variable [ProCGroups.FiniteGroupClass.ContainsTrivialQuotients C]
variable (H : Type u) [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
theorem zcCompletedGroupAlgebraAugmentation_surjective :
    Function.Surjective (zcCompletedGroupAlgebraAugmentation C H)