Stability of C^*-algebra associated with the twisted CCR

The $C^{\ast }$-algebra associated with the twisted CCR constructed by W. Pusz and S.L. Woronowicz is considered. It is proved that the $C^{\ast }$-algebras corresponding to different values of parameter $0<=\mu <1$ are isomorphic. It is proved that Fock representation is faithful on both *-algebra and $C^{\ast }$-algebra levels.