Extending the notion of property T of finite von Neumann algebras to general yon Neu- mann algebras, we define and study in this paper property T** for (possibly non-unital) C*-algebras. We obtain several results...Extending the notion of property T of finite von Neumann algebras to general yon Neu- mann algebras, we define and study in this paper property T** for (possibly non-unital) C*-algebras. We obtain several results of property T** parallel to those of property T for unital C*-algebras. Moreover, we show that a discrete group F has property T if and only if the group C*-algebra C*(F) (or equivalently, the reduced group C*-algebra C*(F)) has property T**. We also show that the compact operators K(g2) has property T** but co does not have property T**.展开更多
文摘Extending the notion of property T of finite von Neumann algebras to general yon Neu- mann algebras, we define and study in this paper property T** for (possibly non-unital) C*-algebras. We obtain several results of property T** parallel to those of property T for unital C*-algebras. Moreover, we show that a discrete group F has property T if and only if the group C*-algebra C*(F) (or equivalently, the reduced group C*-algebra C*(F)) has property T**. We also show that the compact operators K(g2) has property T** but co does not have property T**.