“…[2,3,4,6,7,9]). In particular, there are some complete affirmative answers if M is one of the following: (a) a curve [7], (b) a surface in E 3 [2], (c) a hypersurface in E 4 [6,9]. On the other hand, since there is no assumption of completeness for submanifolds in Conjecture 1, in a sense it is a problem in local differential geometry.…”