Representations of Brauer category and categorification

Abstract

We study representations of the locally unital and locally finite dimensional algebra $B$ associated to the Brauer category $\mathcal B(\delta_0)$ with defining parameter $\delta_0$ over an algebraically closed field $K$ with characteristic $p\neq 2$. The Grothendieck group $K_0(B\text{-mod}^\Delta)$ will be used to categorify the integrable highest weight $\mathfrak {sl}_{K}$-module $ V(\varpi_{\frac{\delta_0-1}{2}})$ with the fundamental weight $\varpi_{\frac{\delta_0-1}{2}}$ as its highest weight, where $B$-mod$^\Delta$ is a subcategory of $B$-lfdmod in which each object has a finite $\Delta$-flag, and $\mathfrak {sl}_{K}$ is either $\mathfrak{sl}_\infty$ or $\hat{\mathfrak{sl}}_p$ depending on whether $p=0$ or $2\nmid p$. As $\mathfrak g$-modules, $\mathbb C\otimes_{\mathbb Z} K_0(B\text{-mod}^\Delta)$ is isomorphic to $ V(\varpi_{\frac{\delta_0-1}{2}})$, where $\mathfrak g$ is a Lie subalgebra of $\mathfrak {sl}_{K}$ (see Definition~4.2). When $p=0$, standard $B$-modules and projective covers of simple $B$-modules correspond to monomial basis and so-called quasi-canonical basis of $V(\varpi_{\frac{\delta_0-1}{2}}) $, respectively.