Families of Gauss indicatrices on Lorentzian hypersurfaces in pseudo-spheres in semi-Euclidean 4-space

摘要

We consider the one-parameter families of Gauss indicatrices on Lorentzian hypersurfaces in pseudo-spheres in semi-Euclidean 4-space with index 2 and give the types of singularities of the Lorentzian hypersurfaces by the contact theory.