On pseudo semi-projective symmetric manifolds

In this paper we introduce a new tensor named semi-projec\-tive curvature tensor which generalizes the projective curvature tensor. First we deduce some basic geometric properties of semi-projective curvature tensor. Then we study pseudo semi-projective symmetric manifolds \linebreak $(PSPS)_{n}$ which recover some known results of Chaki \cite{mcc3}. We provide several interesting results. Among others we prove that in a $(PSPS)_{n}$ if the associated vector field $\rho$ is a unit parallel vector field, then either the manifold reduces to a pseudosymmetric manifold or pseudo projective symmetric manifold. Moreover we deal with semi-projectively flat perfect fluid and dust fluid spacetimes respectively. As a consequence we obtain some important theorems. Next we consider the decomposability of $(PSPS)_{n}$. Finally, we construct a non-trivial Lorentzian metric of $(PSPS)_4$. KCI Citation Count: 0