On a Certain Extension of the Class of Semisymmetric Manifolds
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 conjecture about the Gauss map of complete spacelike surfaces with constant mean curvature in the Lorentz-Minkowski space.
On a Theorem of Chern and Terng on Affine Surfaces.
On acceleration and acceleration axes in dual Lorentzian space .
On almost geodesic mappings between semisymmetric Riemannian spaces.
On almost pseudo-conformally symmetric Ricci-recurrent manifolds with applications to relativity
The object of the present paper is to study almost pseudo-conformally symmetric Ricci-recurrent manifolds. The existence of almost pseudo-conformally symmetric Ricci-recurrent manifolds has been proved by an explicit example. Some geometric properties have been studied. Among others we prove that in such a manifold the vector field corresponding to the 1-form of recurrence is irrotational and the integral curves of the vector field are geodesic. We also study some global properties of such a...
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 CR-lightlike product of an indefinite Kaehler manifold.
On existence of spacelike surfaces with prescribed boundary.
On -planar mappings of (pseudo-) Riemannian manifolds
We study special -planar mappings between two -dimensional (pseudo-) Riemannian manifolds. In 2003 Topalov introduced -projectivity of Riemannian metrics, . Later these mappings were studied by Matveev and Rosemann. They found that for they are projective. We show that -projective equivalence corresponds to a special case of -planar mapping studied by Mikeš and Sinyukov (1983) and -planar mappings (Mikeš, 1994), with . Moreover, the tensor is derived from the tensor and the non-zero...
On generalized curvature tensors on some Riemannian manifolds
On geodesic mappings preserving the Einstein tensor
In this paper there are discussed the geodesic mappings which preserved the Einstein tensor. We proved that the tensor of concircular curvature is invariant under Einstein tensor-preserving geodesic mappings.
On holomorphically projective mappings from equiaffine generally recurrent spaces onto Kählerian spaces
In this paper we consider holomorphically projective mappings from the special generally recurrent equiaffine spaces onto (pseudo-) Kählerian spaces . We proved that these spaces do not admit nontrivial holomorphically projective mappings onto . These results are a generalization of results by T. Sakaguchi, J. Mikeš and V. V. Domashev, which were done for holomorphically projective mappings of symmetric, recurrent and semisymmetric Kählerian spaces.
On holomorphically projective mappings from manifolds with equiaffine connection onto Kähler manifolds
In this paper we study fundamental equations of holomorphically projective mappings from manifolds with equiaffine connection onto (pseudo-) Kähler manifolds with respect to the smoothness class of connection and metrics. We show that holomorphically projective mappings preserve the smoothness class of connections and metrics.
On holomorphically projective mappings of -Kähler manifolds
In this paper we study fundamental equations of holomorphically projective mappings of -Kähler spaces (i.e. classical, pseudo- and hyperbolic Kähler spaces) with respect to the smoothness class of metrics. We show that holomorphically projective mappings preserve the smoothness class of metrics.
On homogeneous conformally symmetric pseudo-Riemannian manifolds
On hypersurfaces in space forms satisfying particular curvature conditions of Tachibana type
On invariant operations on pseudo-Riemannian manifolds
Invariant polynomial operators on Riemannian manifolds are well understood and the knowledge of full lists of them becomes an effective tool in Riemannian geometry, [Atiyah, Bott, Patodi, 73] is a very good example. The present short paper is in fact a continuation of [Slovák, 92] where the classification problem is reconsidered under very mild assumptions and still complete classification results are derived even in some non-linear situations. Therefore, we neither repeat the detailed exposition...