Improper actions and higher connectivity at infinity (Q1567114)

Summary: Given an improper action (= cell stabilizers are infinite) of a group \(G\) on a CW-complex \({\mathcal X}\), we present criteria, based on connectivity at infinity properties of the cell stabilizers under the action of \(G\) that imply connectivity at infinity properties for \(G\). A refinement of this idea yields information on the topology at infinity of Artin groups, and it gives significant progress on the question of which Artin groups are duality groups.