Generalized Robertson–Walker spacetimes extend the notion of Robertson–Walker
spacetimes, by allowing for spatial non-homogeneity. A survey is presented, with main focus …

This paper deals with the study of perfect fluid spacetimes. It is proven that a perfect fluid
spacetime is Ricci recurrent if and only if the velocity vector field of perfect fluid spacetime is …

We set a type of semi-symmetric metric connection on the Lorentzian manifolds. It is proved
that a Lorentzian manifold endowed with a semi-symmetric metric ρ ρ-connection is a GRW …

A perfect-fluid space-time of dimension n≥ 4, with (1) irrotational velocity vector field and (2)
null divergence of the Weyl tensor, is a generalised Robertson-Walker space-time with an …

A generalized Robertson–Walker (GRW) space-time is the generalization of the classical
Robertson–Walker space-time. In the present paper, we show that a Ricci simple manifold …

The derivation-commutator R⋅CC⋅R of a semi-Riemannian manifold (M,g), \dimM≧4,
formed by its Riemann-Christoffel curvature tensor R and the Weyl conformal curvature …

The main goal of this paper is to study the properties of generalized Ricci recurrent perfect
fluid spacetimes and the generalized Ricci recurrent (generalized Robertson–Walker …

In the literature of Riemannian geometry there are many conditions for the equivalency of
semisymmetric (resp., pseudosymmetric) and Ricci-semisymmetric (resp., Ricci …

A survey on generalized Einstein metric conditions Page 36 AMS/IP Studies in Advanced
Mathematics Volume 49, 2011 A Survey on Generalized Einstein Metric Conditions Ryszard …

Abstract The Morris-Thorne wormhole is a spherically symmetric solution of Einstein field
equations with cosmological constant. The present article aims to investigate the geometric …