On some property of the tangency relation of sets.
On some pseudo-symmetric Riemann spaces.
On some rational fibrations with nonvanishing Massey products over homogeneous spaces
The main result of this brief note asserts, incorrectly, that there exists a rational fibration whose total space admits nonzero Massey products. The methods used would be appropriate for showing results of this kind, if the circumstances were to allow for it. Unfortunately the author makes a simple, but nonetheless fatal, computational error in his calculation that ostensibly shows the existence of a nonzero Massey product (p. 249, 1.13: . In fact, for any rational fibration the total space...
On some relations between curvature and metric tensors in Riemannian spaces
The paper generalizes results of H. H. Hacisalihoglu and A. Kh. Amirov [Dokl. Akad. Nauk, Ross. Akad. Nauk 351, No. 3, 295-296 (1996; Zbl 0895.53038) and Sib. Mat. Zh. 39, No. 4, 1005-1012 (1998; Zbl 0913.53019)] on the existence and uniqueness of a Riemannian metric on a domain in given prescribed values for some of the components of the Riemann curvature tensor and initial values of the metric and its partial derivatives. The authors establish the construction (existence and uniqueness) of a...
On some Ricci-flat metrics of cohomogeneity two on complex line bundles.
On some Riemannian manifolds admitting a metric semi-symmetric connection
On some spaces of linear functionals on the algebras for locally compact groups
On some special surfaces connected with convex surfaces of the Lobachevskij space.
On some special vector fields.
On some strictly almost analytic vector fields in tangent bundles
On some structures defined by algebraic equations
On some symplectic quotients of Schubert varieties.
On some type of curvature conditions
In this paper we present a review of recent results on semi-Riemannian manifolds satisfying curvature conditions of pseudosymmetry type.
On some types of slant curves in contact pseudo-Hermitian 3-manifolds
We study slant curves in contact Riemannian 3-manifolds with pseudo-Hermitian proper mean curvature vector field and pseudo-Hermitian harmonic mean curvature vector field for the Tanaka-Webster connection in the tangent and normal bundles, respectively. We also study slant curves of pseudo-Hermitian AW(k)-type.
On Sp(2) and Sp(2) · Sp(1) structures in 8-dimensional vector bundles.
Let ξ be an oriented 8-dimensional vector bundle. We prove that the structure group SO(8) of ξ can be reduced to Sp(2) or Sp(2) · Sp(1) if and only if the vector bundle associated to ξ via a certain outer automorphism of the group Spin(8) has 3 linearly independent sections or contains a 3-dimensional subbundle. Necessary and sufficient conditions for the existence of an Sp(2)- structure in ξ over a closed connected spin manifold of dimension 8 are also given in terms of characteristic classes.
On space forms of Grassmann manifolds.
On Spacelike Hypersurfaces with Constant Mean Curvature in the de Sitter Space.
On space-times with commutative parings of vector fields.
On special almost geodesic mappings of type of spaces with affine connection
N. S. Sinyukov [5] introduced the concept of an almost geodesic mapping of a space with an affine connection without torsion onto and found three types: , and . The authors of [1] proved completness of that classification for .By definition, special types of mappings are characterized by equations where is the deformation tensor of affine connections of the spaces and .In this paper geometric objects which preserve these mappings are found and also closed classes of such spaces...
On special Berwald metrics.