arXiv · math/0603305
We characterize relatively hyperbolic groups whose reduced $C^*$-algebra is simple as those, which have no non-trivial finite normal subgroups.
G. Arzhantseva, A. Minasyan. 2006-03-13. Relatively Hyperbolic Groups are $C^*$-simple. https://arxiv.org/abs/math/0603305
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