Generalized polynomial functors

Abstract: We define Schur categories, $\Gamma^d \mathcal C$, associated to a $\Bbbk$-linear category $\mathcal C$, over a commutative ring $\Bbbk$. The corresponding representation categories, $\mathbf{rep}\, \Gamma^d\mathcal C$, generalize categories of strict polynomial functors. Given a $\Bbbk$-superalgebra $A$, we show that for certain categories $\mathcal{V} = \boldsymbol{\mathcal V}_A$, $\boldsymbol{\mathcal E}_A$ of $A$-supermodules, there is a Morita equivalence between $\mathbf{rep}\, \Gamma^d\mathcal{V}$ and the category of supermodules over a generalized Schur superalgebra of the form $S^A(m|n,d)$ and $S^A(n,d)$, respectively. We also describe a formulation of generalized Schur-Weyl duality from the viewpoint of the category $\mathbf{rep}\, \Gamma^d \boldsymbol{\mathcal E}_A$.