中文摘要：

考虑伪欧氏空间E^5_1中具有三个不同主曲率的非退化Lorentz型双调和超曲面M^4_1.假定其形状算子可对角化,证明了M^4_1是极小的.

英文摘要：

The nondegenerate biharmonic hypersurfaces with three distinct principal curvatures in pseudo-Euclidean space E^5_1 were considered and, under the assumption that the shape operator can be diagonalized, it was proved that such hypersurfaces are minimal.