In ([1]), T. Adati and K. Matsumoto defined para-Sasakian and special para-Sasakian manifolds which are considered as special cases of an almost paracontact manifold introduced by I. Sato and K. Matsumoto ([10]). In the same paper, the authors studied conformally symmetric para-Sasakian manifolds and they proved that an ndimensional (n>3) conformally symmetric para-Sasakian manifold is conforma...

When the Levi-form vanishes at boundary points of a pseudo-convex manifold, more delicate invariants are required to describe the function theoretic properties of the manifold. These are introduced here; the proof of the main theorem and other results, which will be described in more detail elsewhere, are described.

The tangent bundle as a 4n-manifold is equipped with an almost hypercomplex pseudo-Hermitian structure and it is characterized with respect to the relevant classifications. A number of 8-dimensional examples of the considered type of manifold are received from the known explicit examples in that manner.

The motive of this work is to investigate pseudo Z symmetric spacetimes. At first we present some basic properties spacetimes showing that the 1-forms A and B scalars a b associated with spacetime agree specific relation. Next explore conditions under which be GRW quasi-Einstein respectively. Also provide results on Ricci

Lie algebra involutions and their fixed-point subalgebras give rise to symmetric spaces real forms of complex algebras, are well-studied in the context symmetrizable Kac-Moody algebras. In this paper we study a generalization. Namely, introduce concept pseudo-involution, an automorphism which is only required act involutively on stable Cartan subalgebra, pseudo-fixed-point natural substitute fo...