Semi-invariant submanifolds of almost cosymplectic manifolds

This thesis consists of four chapters. The first chapter is introduction. This chapter provides a general knowledge of literature. In the second chapter, we give the basic definitions and concepts. In the third chapter we introduce semi-invariant submanifolds of almost cosymplectic manifolds and we give several properties and search integrability conditions. We also focus mixed totally geodesic of semi-invariant submanifolds of an almost cosymplectic manifold. The last chapter is devoted into results and recommendations.