Li Du’s scientific contributions

... For example, it is shown in [7] that triharmonic CMC surfaces M 2 r with diagonalizable shape operator in E 3 q , or S 3 r +1 (c), or H 3 r (c) are minimal and the same conclusions hold true for hypersurfaces in E 6 q , or S 6 r +1 (c), or H 6 r (c) (cf. [15]). Recently, Du [14] proved that hypersurfaces with at most four distinct principal curvatures in E n+1 q are minimal provided that multiplicity of the zero principle curvature is at most one. ...

Reference:

On minimality and scalar curvature of CMC triharmonic hypersurfaces in pseudo-Riemannian space forms