# On generalized quasi-Einstein GRW space-times

## TL;DR

This paper investigates generalized quasi-Einstein GRW space-times, showing they have constant scalar curvature and reduce to Einstein or perfect fluid space-times, expanding understanding of their geometric and physical properties.

## Contribution

It demonstrates that generalized quasi-Einstein GRW space-times necessarily have constant scalar curvature and simplifies to known space-times, clarifying their structure.

## Key findings

- Generalized quasi-Einstein GRW space-times have constant scalar curvature.
- Such space-times reduce to Einstein or perfect fluid space-times.
- The results extend the classification of GRW space-times.

## Abstract

Recently, it is proven that generalized Robertson-Walker space-times in all orthogonal subspaces of Gray's decomposition but one(unrestricted) are perfect fluid space-times. GRW space-times in the unrestricted subspace are identified by having constant scalar curvature. Generalized quasi-Einstein GRW space-times have a constant scalar curvature. It is shown that generalized quasi-Einstein GRW space-times reduce to Einstein space-times or perfect fluid space-times.