On the lightlike submanifolds of indefinite sasakian manifolds

This thesis consists of four chapters.After introduction, in the second chapter, we give basic materials such as degenerate subspaces, Semi-Riemannian manifolds, distributions, vector bundles, lightlike submanifolds and indefinite Sasakian manifolds which will be useful for other chapters. In the third chapter, we introduce transversal lightlike submanifolds of indefinite Sasakian manifolds and give examples. We also investigate the geometry of leaves and obtain a geometric condition for the induced connection to be a metric connection. Moreover, we study totally contact umbilical transversal lightlike submanifolds and obtain a classification theorem. In the fourth chapter, we introduce screen transversal lightlike submanifolds of indefinite Sasakian manifolds. We give examples, study the geometry of leaves of their distributions and show that any real lightlike curve of an indefinite Sasakian manifold is an example of screen transversal lightlike submanifolds. Finally we study the geometry of totally contact umbilical screen transversal lightlike submanifolds of indefinite Sasakian manifold KEYWORDS: Lightlike Submanifold, İndefinite Sasakian manifold, Transversal lightlike submanifold, Screen transversal lightlike submanifold.