is a semi-Riemannian manifold of dimension
is said to be semisymmetric if
, and Ricci-semisymmetric if
is the Riemann-Christoffel curvature tensor and
is the Ricci tensor on the manifold. In general the first condition implies the second, but not conversely. In this paper the authors construct a class of Ricci-semisymmetric warped products which are not semisymmetric. Examples of Ricci-semisymmetric, non-semisymmetric hypersurfaces in semi-Euclidean space
are given as well.