On Schur rings over infinite groups. III (Q6185347)

A Schur ring over a group \(G\) is a subring of the integral group ring of \(G\) with a \(\mathbb{Z}\)-basis corresponding to a partition of \(G\) into finite subsets satisfying certain conditions. In the paper under review, the authors deal with the case \(G = \mathbb{Z} \times (\mathbb{Z}/p\mathbb{Z})\) where \(p\) is a prime. If \(p\) is a Fermat prime or a safe prime (i.e.\ \(p = 2q+1\) for another prime \(q\)) they obtain a complete classification of all Schur rings over \(G\).