Vanishing branches of the fibre identity #
Non-Eulerian patterns kill every master summand in their fibre: the odd-degree vertex is a block of odd parity.
theorem
RS.masterSummand_vanish_of_not_eulerian
{R : ℕ}
(f : EdgeRankParameter R)
(P : DelignePackage (SkeinObj f))
{k ℓ : ℕ}
(e' : P.ω.obj { arity := 1 } ⟶ stdSuperPair k ℓ)
(W : ClosedFragment)
(c : MixedColouring k ℓ (edgeCount W + edgeCount W))
(s : Finset W.Flag)
(hclosed : ∀ g ∈ s, W.pairing g ∈ s)
(hfibre : colourFlags W c = s)
(hnotE : ¬{ flags := s, pairing_mem := hclosed }.Eulerian)
:
Non-Eulerian vanishing: a colouring whose pattern is a closed non-Eulerian subset has vanishing master summand.
theorem
RS.masterSummand_vanish_of_impure
{R : ℕ}
(f : EdgeRankParameter R)
(P : DelignePackage (SkeinObj f))
{k ℓ : ℕ}
(e' : P.ω.obj { arity := 1 } ⟶ stdSuperPair k ℓ)
(W : ClosedFragment)
(c : MixedColouring k ℓ (edgeCount W + edgeCount W))
(himpure : ¬PairPure c)
:
Impure vanishing: a colouring with a mixed-parity pair has vanishing master summand.
theorem
RS.masterSummand_vanish_of_not_closed
{R : ℕ}
(f : EdgeRankParameter R)
(P : DelignePackage (SkeinObj f))
{k ℓ : ℕ}
(e' : P.ω.obj { arity := 1 } ⟶ stdSuperPair k ℓ)
(W : ClosedFragment)
(c : MixedColouring k ℓ (edgeCount W + edgeCount W))
(s : Finset W.Flag)
(hfibre : colourFlags W c = s)
(hnc : ¬∀ g ∈ s, W.pairing g ∈ s)
:
Non-closed vanishing: a colouring whose pattern is not pairing-closed has vanishing master summand.
The entry of a non-partner odd pair vanishes.
theorem
RS.masterSummand_vanish_of_not_diagonal
{k ℓ R : ℕ}
(f : EdgeRankParameter R)
(P : DelignePackage (SkeinObj f))
(e' : P.ω.obj { arity := 1 } ⟶ stdSuperPair k ℓ)
(W : ClosedFragment)
(c : MixedColouring k ℓ (edgeCount W + edgeCount W))
(hpure : PairPure c)
(hnd : ¬Diagonal W c)
:
Off-diagonal vanishing: a pure non-diagonal colouring has vanishing master summand.