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JMB Journal of Microbiolog and Biotechnology

OPEN ACCESS eISSN 0454-8124
pISSN 1225-6951
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Original Article

Kyungpook Mathematical Journal 2008; 48(2): 183-194

Published online June 23, 2008

Copyright © Kyungpook Mathematical Journal.

Conformally Flat Totally Umbilical Submanifolds in Some Semi-Riemannian Manifolds

Stanis law Ewert-Krzemieniewski

Institute of Mathematics, Szczecin University of Technology, Al. Piast´ow 17, 70310 Szczecin, Poland

Abstract

We prove that totally umbilical submanifold $M$ of an extended quasi-recurren manifold is also extended quasi-recurrent. If, moreover, $M$ is conformally flat then, locally, $M$ is isometric to the manifold with known metric. Some curvature properties of such submanifold are investigated. Making use of these results we shall prove the existence of totally umbilical submanifold being pseudosymmetric in the sense of Ryszard Deszcz and satisfying some other curvature conditions.

Keywords: submanifold, recurrent, quasi-recurrent, extended quasirecurrent, conformally flat, totally umbilical, umbilic, Ricci symmetric, Riccipseudosymmetric, pseudosymmetric, pseudosymmetry