JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, cilt.488, sa.2, 2020 (SCI-Expanded)
In this paper, we consider surfaces in 4-dimensional pseudo-Riemannian space- forms with index 2. First, we obtain some of geometrical properties of such surfaces considering their relative null space. Then, we get classifications of quasi-minimal surfaces with positive relative nullity. (C) 2020 Elsevier Inc. All rights reserved.