Module

Relators.lean

Nyll.ProCGroups.FoxDifferential.Completed.FiniteStage.Stage.Derivative.Relators
11 declarations indexed from sourceView source ↗

Fox differential: finite stage — stage — derivative — relators

The principal declarations in this module are:

  • foxAlgebraicStageLift_right_eq_one_of_mem

If a word lies in N, the finite-stage lift has trivial right component.

  • mem_ker_foxAlgebraicStageLift_iff

Membership in the kernel of the finite Fox stage lift is equivalent to vanishing of the corresponding finite-stage coordinate.

  • ker_foxAlgebraicStageLift_le_foxCommutatorPowerSubgroup_iff

The finite-stage Magnus reverse inclusion is equivalent to the derivative-zero criterion inside \(N\).

  • foxAlgebraicStageSemidirect_commutator_eq_one_of_right_one

In the finite-stage semidirect product, commutators of elements with trivial right component are trivial.

Declarations

FoxDifferential.foxAlgebraicStageLift_right_eq_one_of_mem

If a word lies in N, the finite-stage lift has trivial right component.

Source context 11 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageLift_right_eq_one_of_mem
    {a : FreeGroup X} (ha : a ∈ N) :
    (foxAlgebraicStageLift (X := X) N n a).right = 1
FoxDifferential.mem_ker_foxAlgebraicStageLift_iff

Membership in the kernel of the finite Fox stage lift is equivalent to vanishing of the corresponding finite-stage coordinate.

Source context 11 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem mem_ker_foxAlgebraicStageLift_iff
    {N : Subgroup (FreeGroup X)} [N.Normal] {n : ℕ}
    {w : FreeGroup X} :
    w ∈ (foxAlgebraicStageLift (X := X) N n).ker ↔
      w ∈ N ∧ foxAlgebraicStageDerivativeVector (X := X) N n w = 0
FoxDifferential.ker_foxAlgebraicStageLift_le_foxCommutatorPowerSubgroup_iff

The finite-stage Magnus reverse inclusion is equivalent to the derivative-zero criterion inside \(N\).

Source context 11 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem ker_foxAlgebraicStageLift_le_foxCommutatorPowerSubgroup_iff
    (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ) :
    (foxAlgebraicStageLift (X := X) N n).ker ≤
        foxCommutatorPowerSubgroup (F := FreeGroup X) N n ↔
      ∀ w : FreeGroup X,
        w ∈ N →
        foxAlgebraicStageDerivativeVector (X := X) N n w = 0 →
          w ∈ foxCommutatorPowerSubgroup (F := FreeGroup X) N n
FoxDifferential.foxAlgebraicStageSemidirect_commutator_eq_one_of_right_one

In the finite-stage semidirect product, commutators of elements with trivial right component are trivial.

Source context 12 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
omit [DecidableEq X] in
theorem foxAlgebraicStageSemidirect_commutator_eq_one_of_right_one
    (a b : FoxAlgebraicStageSemidirect (X := X) N n)
    (ha : a.right = 1) (hb : b.right = 1) :
    ⁅a, b⁆ = 1
FoxDifferential.foxAlgebraicStageLift_commutator_eq_one_of_mem

The finite-stage lift kills commutators of words in \(N\).

Source context 11 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageLift_commutator_eq_one_of_mem
    {a b : FreeGroup X} (ha : a ∈ N) (hb : b ∈ N) :
    foxAlgebraicStageLift (X := X) N n ⁅a, b⁆ = 1
FoxDifferential.foxAlgebraicStageSemidirect_pow_right_eq_one_of_right_one

Powers of a finite-stage semidirect element with trivial right component still have trivial right component.

Source context 12 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
omit [DecidableEq X] in
theorem foxAlgebraicStageSemidirect_pow_right_eq_one_of_right_one
    (a : FoxAlgebraicStageSemidirect (X := X) N n)
    (ha : a.right = 1) (m : ℕ) :
    (a ^ m).right = 1
FoxDifferential.foxAlgebraicStageSemidirect_pow_left_of_right_one

Powers of a finite-stage semidirect element with trivial right component scale the left component by the exponent.

Source context 12 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
omit [DecidableEq X] in
theorem foxAlgebraicStageSemidirect_pow_left_of_right_one
    (a : FoxAlgebraicStageSemidirect (X := X) N n)
    (ha : a.right = 1) (m : ℕ) :
    (a ^ m).left = m • a.left
FoxDifferential.foxAlgebraicStageSemidirect_pow_char_eq_one_of_right_one

The \(n\)-th power of a finite-stage semidirect element with trivial right component is trivial over \(\mathbb{Z}/n\mathbb{Z}\).

Source context 12 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
omit [DecidableEq X] in
theorem foxAlgebraicStageSemidirect_pow_char_eq_one_of_right_one
    (a : FoxAlgebraicStageSemidirect (X := X) N n)
    (ha : a.right = 1) :
    a ^ n = 1
FoxDifferential.foxAlgebraicStageLift_pow_eq_one_of_mem

The finite-stage lift kills \(n\)-th powers of words in \(N\).

Source context 11 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageLift_pow_eq_one_of_mem
    {a : FreeGroup X} (ha : a ∈ N) :
    foxAlgebraicStageLift (X := X) N n (a ^ n) = 1
FoxDifferential.foxCommutatorPowerRelatorSet_subset_ker_foxAlgebraicStageLift

The finite Fox commutator-power relators lie in the kernel of the finite-stage lift.

Source context 11 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxCommutatorPowerRelatorSet_subset_ker_foxAlgebraicStageLift :
    foxCommutatorPowerRelatorSet (F := FreeGroup X) N n ⊆
      (foxAlgebraicStageLift (X := X) N n).ker
FoxDifferential.foxCommutatorPowerSubgroup_le_ker_foxAlgebraicStageLift

The finite Fox commutator-power subgroup lies in the kernel of the finite-stage lift.

Source context 11 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
open scoped commutatorElement
universe u v
variable (ℓ : ℕ) [Fact (0 < ℓ)]
variable {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
variable {H : Type v} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxCommutatorPowerSubgroup_le_ker_foxAlgebraicStageLift :
    foxCommutatorPowerSubgroup (F := FreeGroup X) N n ≤
      (foxAlgebraicStageLift (X := X) N n).ker