Canonical bases of the oriented skein category
Yaolong Shen
TL;DR
This work develops a diagrammatic framework for the oriented skein category $\mathcal{OS}(z,t)$, introducing a bar involution and Kazhdan-Lusztig type canonical bases on all morphism spaces. The canonical bases arise from a positive-crossing, reduced-ribbon foundation and are compatible with Lusztig's KL theory, with transition matrices independent of the parameter $t$. By specializing $z$ to $q-q^{-1}$, the quantized walled Brauer algebra $\mathfrak B_{m|n}(q,t)$ is realized as a morphism space in $\mathcal{OS}(q-q^{-1},t)$ and inherits a bar involution and a canonical basis indexed by matchings. The results show positivity in low ranks and suggest deeper connections with quantum group representations via mixed Schur-Weyl duality and HOMFLY-PT skein theory, providing a diagrammatic route to KL-type structures in these algebras.
Abstract
We develop a bar involution and canonical basis for every morphism space of the oriented skein category through a diagrammatic approach. In particular, our construction gives rise to Kazhdan-Lusztig type bases on quantized walled Brauer algebras.
