The geometry of lightlike hypersurfaces of the de Sitter space
arXiv:math/9807013
Abstract
It is proved that the geometry of lightlike hypersurfaces of the de Sitter space S^{n+1}_1 is directly connected with the geometry of hypersurfaces of the conformal space C^n. This connection is applied for a construction of an invariant normalization and an invariant affine connection of lightlike hypersurfaces as well as for studying singularities of lightlike hypersurfaces.
LaTeX, 32 pages;, to be published in Acta Appl.Math., 1998