R₁^m+1中拟迷向类空超曲面

Let f:M^m → R₁^m+1 be an umbilic-free spacelike hypersurface. Four basic conformal invariants of M^m are the conformal metric g, the conformal 1-form C, the conformal second fundamental form B, and the conformal Blaschke tensor A. M^m is called the para-isotropic spacelike hypersurface, if A + μB=λg for some constant μ and smooth function λ. We not only constructed examples which are para-isotropic spacelike hypersurfaces but also classified completely all para-isotropic spacelike hypersurfaces under the conformal transformal group of R₁^m+1 in this paper.