arXiv subjects

Khushwant Singh

Publications and source records attributed to Khushwant Singh.

4 recordsLinked to original sources

arXiv2020

B.-Y. Chen's inequality for $CR$-warped products in a locally conformal Kaehler space form

n this paper, we obtain a geometric inequality between the length of the second fundamental form and the length of Lee form in terms of the warping function for a CR-warped product submanifold in a locally conformal Kaehler space form. The equality case is also investigated. Furthermore, the inequality is discussed for the important subclass of locally conformal Kaehler manifolds i.e., Vaisman manifold.

math.DG↗

arXiv2012

Some inequalities on hemi-slant product submanifolds in a cosymplectic manifold

Recently, M. Atcken studied Contact CR-warped prod- uct submanifolds in cosymplectic space forms and established gen- eral sharp inequalities for CR-warped products in a cosymplectic manifold [1]. In the present paper, we obtain an inequality for the squared norm of the second fundamental form in terms of constant ?$ϕ$-sectional curvature for hemi-slant products in cosymplectic mani- folds. An inequality for hemi-slant warped products in a cosymplectc manifold is also given. The equality case is considered.

math.DG↗

arXiv2012

Warped product contact CR-submanifolds of globally framed f-manifolds with Lorentz metric

In the present paper, we study globally framed f-manifolds in the particular setting of indefinite S-manifolds for both spacelike and timelike cases. We prove that if $M = N^{\perp} \times_f N^T$ is a warped CR-submanifold such that $N^{\perp}$ is $ϕ$?-anti-invariant and NT is $ϕ$?-invariant, then M is a CR-product. We show that the second fundamental form of a contact CR warped product of a indefinite S space form satisfies a geometric inequality, $\|h\|^2 \geq p{3\|\nabla lnf\|^2 - \triangle lnf + (c + 2)k + 1}$.

math.DG↗

arXiv2012

Slant submanifolds of lorentzian almost contact manifolds

In this paper we study slant submanifolds of Lorentzian almost contact manifolds. We have taken the submanifold as a space like and then defined the slant angle on a submanifold and thus we extended the results of A. Lotta (Slant submanifolds in contact geometry [8]) and M. A. Khan et. al. (Slant submanifolds of Lorentzian Paracontact manifolds [7]) in this new setting.

math.DG↗