关键词: laguerre metric, laguerre form, laguerre tensor, laguerre second fundamental form, laguerre isopararmetric hypersurface

Abstract: Let x : M → R ⁿ be an umbilical free hypersurface with non-zero principal curvatures, then x is associated with a Laguerre metric g, a Laguerre tensor L, a Laguerre form C, a Laguerre second fundamental form B, which are invariants of x under Laguerre transformation group. A classical theorem of Laguerre geometry states that M（n > 3） is characterized by g and B up to Laguerre equivalence. A Laguerre isopararmetric hypersurface is defined by satisfying the conditions that C = 0 and all the eigenvalues of B with respect to g are constant. It is easy to see that all Laguerre isopararmetric hypersurfaces are Dupin hypersurfaces. In this paper, we established a complete classification for all Laguerre isopararmetric hypersurfaces with three distinct principal curvatures in R⁷. 

Key words: laguerre metric, laguerre form, laguerre tensor, laguerre second fundamental form, laguerre isopararmetric hypersurface