ON ALGEBRAIC AND GEOMETRIC DIMENSIONS FOR GROUPS WITH TORSION

Abstract

Various notions of dimension for discrete groups are compared. A group is exhibited that acts with finite stabilizers on an acyclic 2-complex in such a way that the fixed point subcomplex for any non-trivial finite subgroup is contractible, but such that the group does not admit any such action on a contractible 2-complex. This group affords a counterexample to a natural generalization of the Eilenberg–Ganea conjecture.