Drinfeld double of quantum groups, tilting modules, and $\mathbb{Z}$-modular data associated to complex reflection groups

Abstract

Generalizing Lusztig’s work, Malle has associated to some imprimitive complex reflection group $W$ a set of “unipotent characters”, which are in bijection of the usual unipotent characters of the associated finite reductive group if $W$ is a Weyl group. He also obtained a partition of these characters into families and associated to each family a $\mathbb{Z}$-modular datum. We construct a categorification of some of these data, by studying the category of tilting modules of the Drinfeld double of the quantum enveloping algebra of the Borel of a simple complex Lie algebra. As an application, we obtain a proof of a conjecture by Cuntz at the decategorified level.