PORTUGALIAE MATHEMATICA Vol. 51, No. 1, pp. 103108 (1994) 

On a Class of Free Galois ExtensionsX.D. Deng and G. SzetoMathematics Department, Zhongshan University,Guangzhou  PEOPLE'S REPUBLIC OF CHINA Mathematics Department, Bradley University, Peoria, Illinois 61625  U.S.A. Abstract: Let $RG_{f}$ be a projective group algebra over a commutative ring $R$, where $G$ is a finite group and $f$ is a factor set. If $RG_{f}$ is a central Galois $R$algebra with inner Galois group $G'$ induced by the basis of $RG_{f}$, then there exists a onetoone correspondence between the set of subgroups $H'$ of $G'$ such that $RH_{f}$ is Galois with a free basis induced by $H'$ and the set of Azumaya subalgebras $B$ over $R$ such that $RG=B(G(B))_{f}$, where $G(B)=\{\alpha\in G\, \alpha(b)=b\}$ for any $b$ in $B$ and $B(G(B))_{f}$ is a projective group ring over $B$. Keywords: Projective group rings and algebras; Azumaya algebras; central Galois algebras; Galois extensions. Classification (MSC2000): 16S35, 16W20 Full text of the article:
Electronic version published on: 29 Mar 2001. This page was last modified: 27 Nov 2007.
© 1994 Sociedade Portuguesa de Matemática
