The center of crossed products over simple rings
The center of crossed products over simple rings
Let $R*G$ be the crossed product of an arbitrary group $G$ over a simple ring $R$. Since $G$ acts on $Z(R)$ and $R$ is simple, $Z(R)$ is a $G$-field and the fixed field $Z(R)^{G}$ of $G$ is contained in $Z(R*G)$. The main result of this paper exhibits a distinguished basis …