# Members & Guests

## Prof. Dr. Kai-Uwe Bux

Universität Bielefeld

E-mail: kaiuwe.bux(at)gmail.com
Telephone: +49 521 106 4988
Homepage: https://www.math.uni-bielefeld.de/~bux/

## Project

8Parabolics and invariants

## Publications within SPP2026

We consider the coset poset associated with the families of proper subgroups, proper subgroups of finite index, and proper normal subgroups of finite index. We investigate under which conditions those coset posets have contractiblegeometric realizations.