The null blow-up of a surface in Minkowski 3-space and intersection in the spacelike Grassmann
The author studies smoothly immersed compact orientable surfaces \(Q\) in a 3 dimensional Minkowski space and decomposes them into a disjoint union \(D^ +\cup D^ 0\cup D^ -\), where the induced metric is positive definite on \(D^ +\), degenerated on \(D^ 0\), and indefinite on \(D^ - \). He constructs a Gauss map for \(D^ 0\) into the compactified spacelike Grassmannian, e.g.: \(D^ 0\to S^ 1\times S^ 1\). Spacelike loops are studied, a degree formula is established, examples and applications are given.
scientific article; zbMATH DE number 59883