de Sitter空间中的紧致正曲率类空子流形

Compact-Positively Curvature Space-Like Submanifoldin de Sitter Space

设Mn是de Sitter空间Spn+p(1)中具有正曲率且法从平坦的n维紧致类空子流形,给出了Mn为全脐子流形的一个充分条件.

Let M^n be a space-like submanifold in a de Sitter space Sp^n＋p（1） with compact-positively curva- ture and flat connection of normal bundle. A sufficient condition is obtained for this kind of space-like submanifold to be totally umbilical.