Results 11 to 20 of about 126 (113)
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
Some Remarks on Quasi-Generalized CR-Null Geometry in Indefinite Nearly Cosymplectic Manifolds
International Journal of Mathematics and Mathematical Sciences, 2016 Attention is drawn to some distributions on ascreen Quasi-Generalized Cauchy-Riemannian (QGCR) null submanifolds in an indefinite nearly cosymplectic manifold. We characterize totally umbilical and irrotational ascreen QGCR-null submanifolds.
Fortuné Massamba, Samuel Ssekajja
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On totally umbilical CR-submanifolds of a Kaehler manifold [PDF]
International Journal of Mathematics and Mathematical Sciences, 1993 Let M be a compact 3-dimensional totally umbilical CR-submanifold of a Kaehler manifold of positive holomorphic sectional curvature. We prove that if the length of the mean curvature vector of M does not vanish, then M is either diffeomorphic to S3 or ...
M. A. Bashir
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Totally umbilical CR-submanifolds of Semi-Riemannian Kaehler manifolds [PDF]
International Journal of Mathematics and Mathematical Sciences, 1987 We study totally umbilical CR-submanifolds of a Kaehler manifold carrying a semi-Riemannian metric. It is shown that for dimension of the totally real distribution greater than one, these submanifolds are locally decomposable into a complex and a totally
K. L. Duggal, R. Sharma
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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
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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
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Pointwise Hemislant Submanifolds in a Complex Space Form
Journal of Mathematics, Volume 2023, Issue 1, 2023., 2023 In this paper, pointwise hemislant submanifolds were introduced in a Kahler manifold. The integrability conditions for the distributions which are involved in the definition of a pointwise hemislant submanifold were investigated. In addition, the necessary and sufficient conditions were given for a pointwise hemislant submanifold to be a pointwise ...
Noura Alhouiti, Antonio Masiello
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A Variational Problem and Classification Theorem for Extremal Hypersurfaces in the Space Form
Journal of Mathematics, Volume 2022, Issue 1, 2022., 2022 The classification of the isoparametric extremal hypersurfaces in the space form is obtained in this paper. We also derived the Euler‐Lagrange equation for extremal hypersurface and obtained Simons’ type integral inequality. When the integral equality holds, we can obtain the characteristics of isoparametric extremal hypersurfaces by using this ...
Yu-Chung Chang, Efthymios G. Tsionas
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Journal of Mathematics, Volume 2021, Issue 1, 2021., 2021 In the present paper, we establish a Chen–Ricci inequality for a C‐totally real warped product submanifold Mn of Sasakian space forms M21m+ε. As Chen–Ricci inequality applications, we found the characterization of the base of the warped product Mn via the first eigenvalue of Laplace–Beltrami operator defined on the warping function and a second‐order ...
Fatemah Mofarreh +4 more
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Chen‐Ricci Inequalities with a Quarter Symmetric Connection in Generalized Space Forms
Advances in Mathematical Physics, Volume 2021, Issue 1, 2021., 2021 In this article, we obtain improved Chen‐Ricci inequalities for submanifolds of generalized space forms with quarter‐symmetric metric connection, with the help of which we completely characterized the Lagrangian submanifold in generalized complex space form and a Legendrian submanifold in a generalized Sasakian space form.
Ali H. Al-Khaldi +4 more
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