ProCGroups.FoxDifferential.Completed.Residue.FreeGroup.Boundary
The principal declarations in this module are:
residueFreeGroupFoxBoundaryThe residue Fox boundary/Euler map \(v \mapsto \sum_i v_i * ([\psi(x_i)]-1)\). -residueFreeGroupFoxBoundary_applyThe residue free-group Fox boundary is evaluated on the canonical generators and then extended linearly to the residue coordinate module. -residueFreeGroupFoxBoundary_singleThe residue Fox boundary sends a coordinate basis vector to the corresponding augmentation generator.
imports
Definition
FoxDifferential.residueFreeGroupFoxBoundary
def residueFreeGroupFoxBoundary (n : ℕ) (ψ : FreeGroup X →* H) :
ResidueFreeFoxCoordinates n H X →ₗ[ResidueGroupRing n H] ResidueGroupRing n H where
toFun v :=
∑ i : X,
v i *
(MonoidAlgebra.of (ModNCompletedCoeff n) H (ψ (FreeGroup.of i)) - 1)
map_add' := by
intro v w
simp only [Pi.add_apply, MonoidAlgebra.of_apply, add_mul, Finset.sum_add_distrib]
map_smul' := by
intro r v
simp only [Pi.smul_apply, smul_eq_mul, MonoidAlgebra.of_apply, mul_assoc, RingHom.id_apply,
Finset.mul_sum]The residue Fox boundary/Euler map \(v \mapsto \sum_i v_i * ([\psi(x_i)]-1)\).
omit [DecidableEq X] in
theorem residueFreeGroupFoxBoundary_apply
(n : ℕ) (ψ : FreeGroup X →* H) (v : ResidueFreeFoxCoordinates n H X) :
residueFreeGroupFoxBoundary n ψ v =
∑ i : X,
v i *
(MonoidAlgebra.of (ModNCompletedCoeff n) H (ψ (FreeGroup.of i)) - 1)The residue free-group Fox boundary is evaluated on the canonical generators and then extended linearly to the residue coordinate module.
Show Lean proof
rfl
@[simp]
theorem residueFreeGroupFoxBoundary_single (n : ℕ) (ψ : FreeGroup X →* H) (i : X) :
residueFreeGroupFoxBoundary n ψ
(Pi.single i (1 : ResidueGroupRing n H)) =
residueGroupRingBoundary n ψ (FreeGroup.of i)The residue Fox boundary sends a coordinate basis vector to the corresponding augmentation generator.
Show Lean proof
by
rw [residueFreeGroupFoxBoundary_apply]
rw [Finset.sum_eq_single i]
· simp only [Pi.single_eq_same, MonoidAlgebra.of_apply, one_mul, residueGroupRingBoundary]
rfl
· intro j _ hji
simp only [Pi.single_eq_of_ne hji, MonoidAlgebra.of_apply, zero_mul]
· simp only [Finset.mem_univ, not_true_eq_false, Pi.single_eq_same, MonoidAlgebra.of_apply,
one_mul,
IsEmpty.forall_iff]