Highest weight theory for minimal finite $W$-superalgebras and related Whittaker categories

TL;DR

This paper develops a highest weight theory for minimal finite W-superalgebras associated with basic classical Lie superalgebras, classifies finite-dimensional irreducible modules, and introduces a category O framework, highlighting new phenomena in the super case.

Contribution

It introduces the highest weight theory and Verma modules for minimal finite W-superalgebras, providing a complete classification of irreducible modules and establishing a category O, with novel features for odd parity cases.

Findings

Complete classification of finite-dimensional irreducible modules.

Introduction of Verma modules via parabolic induction.

Establishment of a highest weight category O for W-superalgebras.

Abstract

Let $\mathfrak{g}=\mathfrak{g}_{\bar0}+\mathfrak{g}_{\bar1}$ be a basic classical Lie superalgebra over $\mathbb{C}$, and $e=e_{\theta}\in\mathfrak{g}_{\bar0}$ with $-\theta$ being a minimal root of $\mathfrak{g}$. Set $U(\mathfrak{g},e)$ to be the minimal finite $W$-superalgebras associated with the pair $(\mathfrak{g},e)$. In this paper we study the highest weight theory for $U(\mathfrak{g},e)$, introduce the Verma modules and give a complete isomorphism classification of finite-dimensional irreducible modules, via the parameter set consisting of pairs of weights and levels. Those Verma modules can be further described via parabolic induction from Whittaker modules for $\mathfrak{osp}(1|2)$ or $\mathfrak{sl}(2)$ respectively, depending on the detecting parity of $\textsf{r}:=\dim\mathfrak{g}(-1)_{\bar1}$. We then introduce and investigate the BGG category $\mathcal{O}$ for $U(\mathfrak{g},e)$, establishing highest weight theory, as a counterpart of the works for finite $W$-algebras by Brundan-Goodwin-Kleshchev and Losev, respectively. In comparison with the non-super case, the significant difference here lies in the situation when $\textsf{r}$ is odd, which is a completely new phenomenon. The difficulty and complicated computation arise from there.