S_1~5中的一类Ⅱ型洛伦兹等参超曲面

A class of lorentzian isoparametric hypersurfaces of form II in S_1~5

研究洛伦兹空间型S1^5中的Ⅱ型洛伦兹等参超曲面，给出了S1^5中最小多项式为λ^2的洛伦兹等参超曲面-↑M的解析表达式.证明了这种超曲面-↑M局部的被三个一元函数C1（t），C2（t），C3（t）所唯一确定，并且S1^5中任何Ⅱ型洛伦兹等参超曲面局部地与最小多项式为λ^2的某个洛伦兹等参超曲面-M的平行超曲面叠合.

In the paper, the isoparametric hypersurfaces in the Lorentzian sphere S1^5 are studied. It is proved that any Lorentzian isoparametric hypersurfaceof type Ⅱ in S1^5 is locally congruent to a parallel hypersurface of a Lorentzian isoparametric -↑M with minimal polynomial λ^2, and -↑M is determined uniquely by three functions C1（t）, C2（t） and C3（t）. Lorentzian isoparametric hypersurface -↑M with minimal polynomial λ^2 in S1^5 the analytic expression is given.