$\delta$(3)-ideal null 2-type hypersurfaces in Euclidean spaces
  In the theory of finite type submanifolds, null 2-type submanifolds are the most simple ones, besides 1-type submanifolds (cf. e.g., [3, 12]). In particular, the classification problems of null 2-type hypersurfaces are quite interesting and of fundamentally important. In this paper, we prove that every $\delta$(3)-ideal null 2-type hypersurface in a Euclidean space has constant mean curvature and constant scalar curvature. 
Bang-Yen Chen and Yu Fu
math.DG