摘要

In this paper we improve the axiom of r-planes(r-spheres) for lightlike submanifolds given by Kumar, Rani and Nagaich. Moreover we introduce another axiom called axiom of r-submanifolds. We prove that if a lightlike submanifold (M,g,S(TM),S(TM perpendicular to)) of a semi-Riemannian manifold ((M) over bar, (g) over bar) satisfies axiom of r-submanifolds, then it is a real space form. We also use Jacobi equation and obtain some related results to totally umbilical lightlilce submanifold of semi-Riemannian manifold.

  • 出版日期2014