On semi-pseudo symmetric and semi-pseudo Ricci-symmetric lorentzian ???? −Kenmotsu manifold

Abstract

The object of this paper is to study a type of Lorentzian ???? −Kenmotsu manifold called Lorentzian ???? − Kenmotsu (????????????)௡ − manifold and Lorentzian ???? − Kenmotsu (????????????????)௡ − manifold (???? ≠ 3). An example of non-existence are also given of such manifolds. Finally, we derive an expression for pressure and density for a perfect flow in the Lorentzian ???? −Kenmotsu manifolds.