$\mathcal{W}$-absorbing actions of finite groups on the Razak-Jacelon algebra

Abstract

We say that a countable discrete group action $\alpha$ on a C${}^{\ast }$-algebra $A$ is \textit{$\mathcal{W}$-absorbing} if there exist a C${}^{\ast }$-algebra $B$ and an action $\beta$ on $B$ such that $\alpha$ is cocycle conjugate to $\beta \otimes {\mathrm{id}}_{\mathcal{W}}$ on $B\otimes \mathcal{W}$ where $\mathcal{W}$ is the Razak-Jacelon algebra. In this paper, we completely classify outer $\mathcal{W}$-absorbing actions of finite groups on $\mathcal{W}$ up to conjugacy and cocycle conjugacy.

27 pages