The top braiding through the merge #
The braiding of the last two strands commutes with the block merge: whiskering the two-strand braid inside the last block and merging equals merging and braiding on top. Abstract braided coherence first, instantiated to the powers.
theorem
RS.powMerge_topBraid
(V : SuperVect)
(a : ℕ)
:
CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.whiskerLeft (superPow V a) (topBraid V 0))
(powMerge V a 2) = CategoryTheory.CategoryStruct.comp (powMerge V a 2) (topBraid V a)
The merge-braid exchange on powers: braiding inside the last two-strand block and merging equals merging and braiding on top.
The block merge is an isomorphism.
theorem
RS.powMerge_evenMap_surjective
(V : SuperVect)
(a b : ℕ)
:
Function.Surjective ⇑(powMerge V a b).evenMap
Every power element is a merge image.
theorem
RS.powMerge_oddMap_surjective
(V : SuperVect)
(a b : ℕ)
:
Function.Surjective ⇑(powMerge V a b).oddMap
Every odd power element is a merge image.