Results 11 to 20 of about 1,215 (136)

Some remarks on quasi generalized CR-null geometry in indefinite nearly cosymplectic manifolds

International Journal of Mathematics and Mathematical Sciences, Volume 2016, Issue 1, 2016., 2016
In [21], the authors initiated the study of quasi generalized CR (QGCR)-null submanifolds. In this paper, attention is drawn to some distributions on ascreen QGCR-null submanifolds in an indefinite nearly cosymplectic manifold.
Massamba, Fortuné, Ssekajja, Samuel
core   +3 more sources

A Classification of a Totally Umbilical Slant Submanifold of Cosymplectic Manifolds [PDF]

Abstract and Applied Analysis, 2012
We study slant submanifolds of a cosymplectic manifold. It is shown that a totally umbilical slant submanifold 𝑀 of a cosymplectic manifold 𝑀 is either an anti-invariant submanifold or a 1−dimensional submanifold.
Siraj Uddin, Cenap Ozel, Viqar Azam Khan
doaj   +5 more sources

Planar Pseudo-geodesics and Totally Umbilic Submanifolds [PDF]

The Journal of Geometric Analysis, 2023
AbstractWe study totally umbilic isometric immersions between Riemannian manifolds. First, we provide a novel characterization of the totally umbilic isometric immersions with parallel normalized mean curvature vector, i.e., those having nonzero mean curvature vector and such that the unit vector in the direction of the mean curvature vector is ...
Steen Markvorsen, Matteo Raffaelli
openalex   +6 more sources

ON TOTALLY UMBILICAL SUBMANIFOLDS OF SOME CLASS RIEMANNIAN MANIFOLDS [PDF]

Demonstratio Mathematica, 1983
The authors study totally umbilical submanifolds M with parallel mean curvature vector in pseudo-Riemannian manifolds N, such that the curvature tensor R of M satisfies \(R(X,Y)\cdot R=0\), while N carries a generalized curvature tensor \(\tilde T\) with \(\tilde R\)(X,Y)\(\cdot \tilde T=0\), \(\tilde R\) being the curvature of N.
Adam Adamów, Ryszard Deszcz
openalex   +3 more sources

Generalized Robertson-Walker Space-Time Admitting Evolving Null Horizons Related to a Black Hole Event Horizon. [PDF]

Int Sch Res Notices, 2016
A new technique is used to study a family of time‐dependent null horizons, called “Evolving Null Horizons” (ENHs), of generalized Robertson‐Walker (GRW) space‐time (M¯,g¯) such that the metric g¯ satisfies a kinematic condition. This work is different from our early papers on the same issue where we used (1 + n)‐splitting space‐time but only some ...
Duggal KL.
europepmc   +2 more sources

On totally umbilical submanifolds of Finsler spaces [PDF]

Annales Polonici Mathematici, 2010
The authors define totally umbilical submanifolds of Finsler manifolds using the second fundamental form introduced by Q. He and Y. B. Shen. They study totally umbilical submanifolds of Finsler manifolds establishing some simpler equations related to curvatures of Finsler submanifolds and the curvatures of the ambient space.
Qun He, Wei Yang, Wei Zhao
openalex   +2 more sources

TOTALLY UMBILICAL CR-SUBMANIFOLDS OF A KAEHLER MANIFOLD

Tamkang Journal of Mathematics, 1993
In the present paper we study totally umbilical CR-submanifolds of a Kaehler manifold. A classification theorem for a $D^\perp$-totally umbilical CR-submanifold is proved. The conditions under which a CR- submanifold becomes a CR-product are obtained, and finally a theorem for a CR-submanifold to be a proper CR-product is also ...
Syed Mahmood Haider, Vakeel A. Khan, Shamshad Husain   +2 more
openalex   +4 more sources

Pseudo-totally umbilical lightlike submanifolds

Hacettepe Journal of Mathematics and Statistics, 2022
We introduce the geometry of pseudo-totally umbilical lightlike submanifold $M$ of a semi-Riemannian manifold $\bar{M}$. In line with the above, we give a complete classification of pseudo-totally umbilical $1$-lightlike submanifolds, such as the lightlike hypersurfaces and half-lightlike submanifolds.
Samuel Ssekajja
openalex   +4 more sources

TOTALLY UMBILICAL CR-SUBMANIFOLDS OF KÄHLER MANIFOLDS [PDF]

TRU Mathematics, 1985
The authors prove the following important result. Any connected non totally geodesic but totally umbilical proper CR-submanifold of dimension greater than 4 in a Kähler manifold is a Sasakian manifold.
TOSHITAKA TOYONARI, Hiroaki Nemoto
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Totally umbilical submanifolds of a Kaehlerian manifold [PDF]

Journal of the Mathematical Society of Japan, 1967
Masafumi Okumura
openalex   +4 more sources