Title: On the Pseudo-Riemannian spaces with a special structure of a curvature tensor
Abstract: The paper treats pseudo-Riemannian spaces with the Riemann tensor of a particular structure. Riemann tensor's structure is defined by combinations of special symmetric and skew symmetric tensors. It is proved for every type of these spaces that the latter commute with Ricci tensor. The research is carried out in tensor form, without any limitations on a sign of a metric.