Decategorified Heegaard Floer theory and actions of both $E$ and $F$

Abstract

We define larger variants of the vector spaces one obtains by decategorifying bordered (sutured) Heegaard Floer invariants of surfaces. We also define bimodule structures on these larger spaces that are similar to, but more elaborate than, the bimodule structures that arise from decategorifying the higher actions in bordered Heegaard Floer theory introduced by Rouquier and the author. In particular, these new bimodule structures involve actions of both odd generators $E$ and $F$ of $\mathfrak{gl}(1|1)$, whereas the previous ones only involved actions of $E$. Over $\mathbb{F}_2$, we show that the new bimodules satisfy the necessary gluing properties to give a 1+1 open-closed TQFT valued in graded algebras and bimodules up to isomorphism; in particular, unlike in previous related work we have a gluing theorem when gluing surfaces along circles as well as intervals. Over the integers, we show that a similar construction gives two partially-defined open-closed TQFTs with two different domains of definition depending on how parities are chosen for the bimodules. We formulate conjectures relating these open-closed TQFTs with the $\mathfrak{psl}(1|1)$ Chern--Simons TQFT recently studied by Mikhaylov and Geer--Young.