Model actions for almost reduced groups on UHF algebras

Abstract

For any countable discrete group $G$ with a reduced abelian subgroup of finite index, we construct an action $\hat{I}\pm$ of $G$ on the universal UHF algebra $\Qq$ using an infinite tensor product of permutation representations of $G$ and show that these actions possess some sort of Rokhlin property. The crossed product $\qag$ is then deduced to be tracially AF with a unique tracial state. We also compute the Elliott invariants in the case that $G$ is abelian.

11 pages. Comments welcome