Exotic group C*-algebras

Abstract: Let $\Gamma$ be a discrete group. When $\Gamma$ is nonamenable, the reduced and full group $C$-algebras differ and it is generally believed that there should be many intermediate $C$-algebras, however few examples are known. In this paper we give new constructions and compare existing constructions of intermediate group $C$*-algebras for both generic and specific groups $\Gamma$.