Certain conditions for a Riemannian manifold to be isometric with a sphere:Dedicated to Professor Kentaro Yano on his fiftieth birthday

Integral formulas in Riemannian geometry

In this paper we give some examples of a quasi Einstein manifold (QE)n. Next we prove the existence of (QE)n manifolds. Then we study some properties of a quasi Einstein manifold. Finally the hypersurfaces of a Euclidean space have been studied.

On quasi Einstein manifolds

We show that an n-dimensional generalized Robertson–Walker (GRW) space-time with divergence-free conformal curvature tensor exhibits a perfect fluid stress–energy tensor for any f(R) gravity model....

Cosmological perfect-fluids in f(R) gravity

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

Generalized Robertson-Walker spacetimes — A survey

The object of the present paper is to study a type of Riemannian manifold called generalized quasi Einstein manifold

On Generalized Quasi Einstein Manifolds

Quasi Einstein manifold is a simple and natural generalization of an Einstein manifold. The object of the present paper is to study some geometric properties of generalized quasi Einstein manifolds. Two non-trivial examples have been constructed to prove the existence of a generalized quasi Einstein manifold.

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On generalized quasi einstein manifolds

We consider a semisymmetric metric connection in an almost Kenmotsu manifold with its characteristic vector field ξ belonging to the (k, μ)′-nullity distribution and (k, μ)-nullity distribution respectively. We first obtain the expressions of the curvature tensor and Ricci tensor with respect to the semisymmetric metric connection in an almost Kenmotsu manifold with ξ belonging to (k, μ)′and (k, μ)-nullity distribution respectively. Then we characterize an almost Kenmotsu manifold with ξ belonging to (k, μ)′-nullity distribution admitting a semisymmetric metric connection.

Gopal Chandra Ghosh

Papers

On quasi Einstein manifolds

On Generalized Quasi Einstein Manifolds

On generalized quasi einstein manifolds

On a Semi-symmetric Metric Connection in an Almost Kenmotsu Manifold with Nullity Distributions

Generalized Ricci solitons on contact metric manifolds