Lightlike flat geometry of spacelike submanifolds in Lorentz–Minkowski space

Abstract

In this paper, we investigate differential geometry on spacelike submanifolds in Lorentz–Minkowski space from the viewpoint of contact with lightlike hyperplanes. It is called the lightlike flat geometry which has been well established for the codimension-two case. In order to develop the theory for the general codimension-case, we introduce the notion of codimension-two spacelike canal submanifolds which is a main tool in this paper. We apply the theory of Lagrangian/Legendrian singularities to codimension-two spacelike canal submanifolds and obtain the relation with the previous results on the codimension-two case.