Isometric immersions of two-dimensional Riemannian manifolds in pseudo- Euclidean space (Q1062292)

The main result of this paper is the following theorem: Every complete two-dimensional Riemannian manifold M of class \(C^ r(C^{\alpha})\) (1\(\leq r\leq \infty)\), conformally equivalent to a manifold of constant nonnegative curvature, admits an isometric immersion of the same class in an isotropic hypercone of the pseudo-Euclidean space \(E^{n,1}\) (4\(\leq n\leq 7)\).