Almost finiteness and homology of certain non-free actions

Abstract

We show that Cantor minimal $\mathbb{Z}⋊{\mathbb{Z}}_2$-systems and essentially free amenable odometers are almost finite. We also compute the homology groups of Cantor minimal $\mathbb{Z}⋊{\mathbb{Z}}_2$-systems and show that the associated transformation groupoids satisfy the HK conjecture if and only if the action is free.

12 pages. Minor corrections. Accepted in Groups, Geometry and Dynamics