On the separability problem for circulant S-rings

A Schur ring (S-ring) over a group $G$ is said to be separable if every of its similaritities is induced by an isomorphism. A criterion is established for an S-ring to be separable in the case where the group $G$ is cyclic. Using this criterion, it is proved that any S-ring over a cyclic $p$-group is separable and that the class of separable circulant S-rings is closed with respect to duality.