The geometric invariants \(\Sigma^*\) of a group refine finiteness properties: a point in \(\Sigma^{1}(G)\) can be thought of as a direction toward infinity along which the group \(G\) is finitely generated, a point in \(\Sigma^{2}(G)\) corresponds to a direction toward infinity in which \(G \) is finitely presented, and so on for higher invariants. Our main objectives concern the geometric invariants of arithmetic groups. Since arithmetic groups are lattices in locally compact groups we also want to develop the theory of higher \(\Sigma\)-invariants of locally compact groups (recently discovered by Schick and Bux) and elucidate the relationship of the geometric invariants of lattices and their ambient locally compact groups.
Publications
Team Members
Prof. Dr. Kai-Uwe Bux
Project leader
Universität Bielefeld
kaiuwe.bux(at)gmail.com
Dr. Dorian Chanfi
Researcher
JLU Gießen
dorian.chanfi(at)math.uni-giessen.de
Prof. Dr. Stefan Witzel
Project leader
JLU Gießen
stefan.witzel(at)math.uni-giessen.de