Module

Basic.lean

Nyll.ProCGroups.FoxDifferential.Completed.FiniteStage.Stage.Derivative.Quotient.Basic
15 declarations indexed from sourceView source ↗

Fox differential: stage — derivative — quotient — basic

The principal declarations in this module are:

  • foxAlgebraicStageQuotientLift

The finite-stage lift descended to the source quotient \(F/[N,N]N^n\).

  • foxAlgebraicStageQuotientCoefficient

Coefficient homomorphism for the finite-stage quotient crossed homomorphism.

  • foxAlgebraicStageQuotientLift_mk

Evaluation of the descended finite-stage lift on a representative.

  • foxAlgebraicStageQuotientLift_right

The right component of the descended finite-stage lift is the quotient map from \(F/[N,N]N^n\) to \(F/N\).

Declarations

FoxDifferential.foxAlgebraicStageQuotientLift

The finite-stage lift descended to the source quotient \(F/[N,N]N^n\).

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
def foxAlgebraicStageQuotientLift :
    FreeGroup X ⧸ foxCommutatorPowerSubgroup (F := FreeGroup X) N n →*
      FoxAlgebraicStageSemidirect (X := X) N n
FoxDifferential.foxAlgebraicStageQuotientLift_mk

Evaluation of the descended finite-stage lift on a representative.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageQuotientLift_mk (w : FreeGroup X) :
    foxAlgebraicStageQuotientLift (X := X) N n
        (QuotientGroup.mk'
          (foxCommutatorPowerSubgroup (F := FreeGroup X) N n) w) =
      foxAlgebraicStageLift (X := X) N n w
FoxDifferential.foxAlgebraicStageQuotientLift_right

The right component of the descended finite-stage lift is the quotient map from \(F/[N,N]N^n\) to \(F/N\).

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageQuotientLift_right
    (q : FreeGroup X ⧸ foxCommutatorPowerSubgroup (F := FreeGroup X) N n) :
    (foxAlgebraicStageQuotientLift (X := X) N n q).right =
      foxCommutatorPowerQuotientMapToNormalQuotient (F := FreeGroup X) N n q
FoxDifferential.foxAlgebraicStageQuotientCoefficient

Coefficient homomorphism for the finite-stage quotient crossed homomorphism.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
def foxAlgebraicStageQuotientCoefficient :
    (FreeGroup X ⧸ foxCommutatorPowerSubgroup (F := FreeGroup X) N n) →*
      foxAlgebraicStageTargetGroupAlgebra (X := X) N n
FoxDifferential.foxAlgebraicStageQuotientDerivativeVector

The finite-stage derivative vector descended to \(F/[N,N]N^n\), bundled with its scalar Fox--Leibniz law.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
def foxAlgebraicStageQuotientDerivativeVector :
    ScalarCrossedHom
      (foxAlgebraicStageQuotientCoefficient (X := X) N n)
      (foxAlgebraicStageCoordinateVector (X := X) N n) where
  toFun q := (foxAlgebraicStageQuotientLift (X := X) N n q).left
  map_mul' := by
    intro q r
    simp only [scalarCrossedAction_apply, map_mul,
      FoxAlgebraicStageSemidirect.mul_left,
      foxAlgebraicStageQuotientLift_right,
      foxAlgebraicStageQuotientCoefficient, MonoidHom.coe_comp,
      Function.comp_apply, MonoidAlgebra.of_apply]
FoxDifferential.foxAlgebraicStageQuotientDerivativeVector_mk

Evaluation of the descended derivative vector on a representative.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageQuotientDerivativeVector_mk (w : FreeGroup X) :
    foxAlgebraicStageQuotientDerivativeVector (X := X) N n
        (QuotientGroup.mk'
          (foxCommutatorPowerSubgroup (F := FreeGroup X) N n) w) =
      foxAlgebraicStageDerivativeVector (X := X) N n w
FoxDifferential.foxAlgebraicStageQuotientDerivative

A coordinate of the descended finite-stage derivative on the source quotient.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
def foxAlgebraicStageQuotientDerivative (i : X)
    (q : FreeGroup X ⧸ foxCommutatorPowerSubgroup (F := FreeGroup X) N n) :
    foxAlgebraicStageTargetGroupAlgebra (X := X) N n
FoxDifferential.foxAlgebraicStageQuotientDerivative_mk

Evaluation of a descended derivative coordinate on a representative.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageQuotientDerivative_mk (i : X) (w : FreeGroup X) :
    foxAlgebraicStageQuotientDerivative (X := X) N n i
        (QuotientGroup.mk'
          (foxCommutatorPowerSubgroup (F := FreeGroup X) N n) w) =
      foxAlgebraicStageDerivative (X := X) N n i w
FoxDifferential.foxAlgebraicStageQuotientCoefficient_apply

The finite Fox-stage quotient coefficient is evaluated by projecting the group coordinate and reducing the coefficient.

Source context 8 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
omit [DecidableEq X] in
theorem foxAlgebraicStageQuotientCoefficient_apply
    (q : FreeGroup X ⧸ foxCommutatorPowerSubgroup (F := FreeGroup X) N n) :
    foxAlgebraicStageQuotientCoefficient (X := X) N n q =
      MonoidAlgebra.of (ModNCompletedCoeff n)
        (foxAlgebraicStageTargetQuotient (X := X) N)
        (foxCommutatorPowerQuotientMapToNormalQuotient (F := FreeGroup X) N n q)
FoxDifferential.foxAlgebraicStageQuotientCoefficient_mk

The quotient coefficient homomorphism agrees with the free-group coefficient homomorphism on representatives.

Source context 8 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
omit [DecidableEq X] in
theorem foxAlgebraicStageQuotientCoefficient_mk (w : FreeGroup X) :
    foxAlgebraicStageQuotientCoefficient (X := X) N n
        (QuotientGroup.mk'
          (foxCommutatorPowerSubgroup (F := FreeGroup X) N n) w) =
      foxAlgebraicStageCoefficient (X := X) N n w
FoxDifferential.foxAlgebraicStageQuotientDerivative_one

The descended finite-stage derivative sends the identity word to zero componentwise.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageQuotientDerivative_one (i : X) :
    foxAlgebraicStageQuotientDerivative (X := X) N n i
        (1 : FreeGroup X ⧸ foxCommutatorPowerSubgroup (F := FreeGroup X) N n) = 0
FoxDifferential.foxAlgebraicStageQuotientDerivativeVector_of

Generator value for the descended finite-stage derivative vector.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageQuotientDerivativeVector_of (x : X) :
    foxAlgebraicStageQuotientDerivativeVector (X := X) N n
        (QuotientGroup.mk'
          (foxCommutatorPowerSubgroup (F := FreeGroup X) N n) (FreeGroup.of x)) =
      Pi.single x (1 : foxAlgebraicStageTargetGroupAlgebra (X := X) N n)
FoxDifferential.foxAlgebraicStageQuotientDerivative_of

At a generator, the descended finite-stage derivative has the corresponding component value.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageQuotientDerivative_of (i x : X) :
    foxAlgebraicStageQuotientDerivative (X := X) N n i
        (QuotientGroup.mk'
          (foxCommutatorPowerSubgroup (F := FreeGroup X) N n) (FreeGroup.of x)) =
      (Pi.single x (1 : foxAlgebraicStageTargetGroupAlgebra (X := X) N n) :
        X → foxAlgebraicStageTargetGroupAlgebra (X := X) N n) i
FoxDifferential.foxAlgebraicStageQuotientDerivativeVector_unique

The bundled descended derivative vector is uniquely determined by its values on quotient generators.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem foxAlgebraicStageQuotientDerivativeVector_unique
    (delta : ScalarCrossedHom
      (foxAlgebraicStageQuotientCoefficient (X := X) N n)
      (foxAlgebraicStageCoordinateVector (X := X) N n))
    (hbasis :
      ∀ x : X,
        delta
          (QuotientGroup.mk'
            (foxCommutatorPowerSubgroup (F := FreeGroup X) N n)
            (FreeGroup.of x)) =
          Pi.single x (1 : foxAlgebraicStageTargetGroupAlgebra (X := X) N n)) :
    delta = foxAlgebraicStageQuotientDerivativeVector (X := X) N n
FoxDifferential.existsUnique_foxAlgebraicStageQuotientDerivativeVector

Existence and uniqueness theorem for the descended finite-stage Fox derivative vector on the finite source quotient.

Source context 7 commands

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

namespace FoxDifferential
noncomputable section
open ProCGroups.InverseSystems
open ProCGroups.ProC
universe u
variable {X : Type u} [DecidableEq X]
variable (N : Subgroup (FreeGroup X)) [N.Normal] (n : ℕ)
theorem existsUnique_foxAlgebraicStageQuotientDerivativeVector :
    ∃! delta : ScalarCrossedHom
        (foxAlgebraicStageQuotientCoefficient (X := X) N n)
        (foxAlgebraicStageCoordinateVector (X := X) N n),
      ∀ x : X,
        delta
          (QuotientGroup.mk'
            (foxCommutatorPowerSubgroup (F := FreeGroup X) N n)
            (FreeGroup.of x)) =
          Pi.single x (1 : foxAlgebraicStageTargetGroupAlgebra (X := X) N n)