On 3-Dimensional Riemannian ...-Spaces.
On -dimensional Lie groups as quasi-Kähler manifolds with Killing Norden metric.
On a Class of Generalized quasi-Einstein Manifolds with Applications to Relativity
Quasi Einstein manifold is a simple and natural generalization of Einstein manifold. The object of the present paper is to study some properties of generalized quasi Einstein manifolds. We also discuss with space-matter tensor and some properties related to it. Two non-trivial examples have been constructed to prove the existence of generalized quasi Einstein spacetimes.
On a class of Ricci-recurrent manifolds.
On a variational theory of light rays on Lorentzian manifolds
In this Note, by using a generalization of the classical Fermat principle, we prove the existence and multiplicity of lightlike geodesics joining a point with a timelike curve on a class of Lorentzian manifolds, satisfying a suitable compactness assumption, which is weaker than the globally hyperbolicity.
On canonical screen for lightlike submanifolds of codimension two
In this paper we study two classes of lightlike submanifolds of codimension two of semi-Riemannian manifolds, according as their radical subspaces are 1-dimensional or 2-dimensional. For a large variety of both these classes, we prove the existence of integrable canonical screen distributions subject to some reasonable geometric conditions and support the results through examples.
On certain Einstein space-time
On complete linear Weingarten hypersurfaces in locally symmetric Riemannian manifolds
Our aim is to apply suitable generalized maximum principles in order to obtain characterization results concerning complete linear Weingarten hypersurfaces immersed in a locally symmetric Riemannian manifold, whose sectional curvature is supposed to obey standard constraints. In this setting, we establish sufficient conditions to guarantee that such a hypersurface must be either totally umbilical or an isoparametric hypersurface with two distinct principal curvatures one of which is simple.
On complete spacelike hypersurfaces with in locally symmetric Lorentz spaces
In this note, we investigate -dimensional spacelike hypersurfaces with in locally symmetric Lorentz space. Two rigidity theorems are obtained for these spacelike hypersurfaces.
On conformally flat Lorentz parabolic manifolds
We introduce conformally flat Fefferman-Lorentz manifold of parabolic type as a special class of Lorentz parabolic manifolds. It is a smooth (2n+2)-manifold locally modeled on (Û(n+1, 1), S 2n+1,1). As the terminology suggests, when a Fefferman-Lorentz manifold M is conformally flat, M is a Fefferman-Lorentz manifold of parabolic type. We shall discuss which compact manifolds occur as a conformally flat Fefferman-Lorentz manifold of parabolic type.
On Conjugate and Focal Points in Semi-Riemannian Geometry.
On equivariant harmonic maps defined on a Lorentz manifold
In this paper, we prove by using the minimax principle that there exist infinitely many -equivariant harmonic maps from a specific Lorentz manifold to a compact Riemannian manifold.
On Existence and Comparison of Conjugate Points in Riemannian and Lorentzian Geometry.
On finite type closed curves on the pseudo-hyperbolic space .
On generalized curvature tensors on some Riemannian manifolds
On geometry of flat complete strictly causal Lorentzian manifolds.
On Hb-flat Hyperbolic Kaehlerian Spaces
On homogeneous conformally symmetric pseudo-Riemannian manifolds
On Isometric Immersions of the Hyperbolic Plane Into the Lorentz-Minkowski Space and the Monge-Ampère Equation of a Certain Type.
On Maximal Geodesic-Diameter and Causality in Lorentz Manifolds.