On boundaries of unions of sets with positive reach.
On Calabi's conjecture for complex surfaces with positive first Chern class.
On calibrations for Lawson’s cones
On canonical forms on non-holonomic and semi-holonomic prolongations of principal fibre bundles
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 Cauchy-Riemann submanifolds whose local geodesic symmetries preserve the fundamental form
We classify generic Cauchy-Riemann submanifolds (of a Kaehlerian manifold) whose fundamental form is preserved by any local geodesic symmetry.
On certain anti-invariant submanifolds of an S-manifold
On certain Einstein space-time
On certain four-dimensional almost Kähler manifolds
We study four-dimensional almost Kähler manifolds (M,g,J) which admit an opposite almost Kähler structure.
On certain groups of holomorphic maps
On certain real hypersurfaces of quaternionic projective space.
On certain structures on the frame bundle of an almost para-contact metric manifold
On Cheeger's inequality.
On Circles and Spheres in Riemannian Geometry.
On Clifford-type structures [Book]
On closed concircular almost contact Riemannian manifolds.
On Codimension-one Foliations of Constant Mean Curvature.
On compact astheno-Kähler manifolds
We prove that every compact balanced astheno-Kähler manifold is Kähler, and that there exists an astheno-Kähler structure on the product of certain compact normal almost contact metric manifolds.
On compact holomorphically pseudosymmetric Kählerian manifolds
For compact Kählerian manifolds, the holomorphic pseudosymmetry reduces to the local symmetry if additionally the scalar curvature is constant and the structure function is non-negative. Similarly, the holomorphic Ricci-pseudosymmetry reduces to the Ricci-symmetry under these additional assumptions. We construct examples of non-compact essentially holomorphically pseudosymmetric Kählerian manifolds. These examples show that the compactness assumption cannot be omitted in the above stated theorem....
On compact homogeneous symplectic manifolds
In this paper the authors study compact homogeneous spaces (of a Lie group ) on which there if defined a -invariant symplectic form . It is an important feature of the paper that very little is assumed concerning and . The essential assumptions are: (1) is connected and (2) is uniform (i.e., is compact). Further, for convenience only and with no loss of generality, it is supposed that is simply connected and contains no connected normal subgroup of , i.e., that acts almost effectively...