Published online by Cambridge University Press: 18 January 2013
We study the space of irreducible representations of a crossed product ${C}^{\ast } $-algebra
${\mathop{A\rtimes }\nolimits}_{\sigma } G$, where
$G$ is a finite group. We construct a space
$\widetilde {\Gamma } $ which consists of pairs of irreducible representations of
$A$ and irreducible projective representations of subgroups of
$G$. We show that there is a natural action of
$G$ on
$\widetilde {\Gamma } $ and that the orbit space
$G\setminus \widetilde {\Gamma } $ corresponds bijectively to the dual of
${\mathop{A\rtimes }\nolimits}_{\sigma } G$.