The object of the present paper is to study weakly cyclic Z symmetric spacetimes. At first we prove that a weakly cyclic Z symmetric spacetime is a quasi Einstein spacetime. Then we study (WCZS) 4 spacetimes satisfying the condition div C= 0. Next we consider conformally flat (WCZS) 4 spacetimes. Finally, we characterise dust fluid and viscous fluid (WCZS) 4 spacetimes. © 2016, Akadémiai Kiadó, Budapest, Hungary.

U C DE

C A MANTICA

L G MOLINARI

Y J SUH

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Acta Mathematica Hungarica

Fulltext

Journal of Mathematical Physics

Erratum to "A condition for a perfect-fluid space-time to be a generalized Robertson-Walker space-time" [J. Math. Phys. 57, (2016), 022508]

The object of the present paper is to study weakly cyclic Z symmetric manifolds. Some geometric properties have been studied. We obtain a sufficient condition for a weakly cyclic Z symmetric manifold to be a quasi Einstein manifold. Next we consider conformally flat weakly cyclic Z symmetric manifolds. Then we study Einstein (WCZS)n (n &gt; 2). Also we study decomposable (WCZS)n (n &gt; 2). We prove the equivalency of semisymmetry and Weyl-semisymmetry in a (WCZS)n (n &gt; 2). Finally, we give an example of a (WCZS)4. © 2014, Akadémiai Kiadó, Budapest, Hungary.

On weakly cyclic Z symmetric manifolds

We consider a conformally flat almost pseudo-Ricci symmetric spacetime. At first we show that a conformally flat almost pseudo-Ricci symmetric spacetime can be taken as a model of the perfect fluid spacetime in general relativity and cosmology. Next we show that if in a conformally flat almost pseudo-Ricci symmetric spacetime the matter distribution is perfect fluid whose velocity vector is the vector field corresponding to 1-form B of the spacetime, the energy density and the isotropic pressure are not constants. We also show that a conformally flat almost pseudo-Ricci symmetric spacetime is the Robertson-Walker spacetime. Finally we give an example of a conformally flat almost pseudo-Ricci symmetric spacetime with non-zero non-constant scalar curvature admitting a concircular vector field. © 2012 Springer Science+Business Media, LLC.

International Journal of Theoretical Physics

On Conformally Flat Almost Pseudo-Ricci Symmetric Spacetimes

It is shown that a general relativistic space-time with covariant-constant energy-momentum tensor is Ricci symmetric. Two particular types of such general relativistic space-times are considered and the nature of each is determined.

Journal	Data powered by TypesetActa Mathematica Hungarica
Publisher	Data powered by TypesetSpringer Netherlands
ISSN	0236-5294