@misc{10481/90079,
year = {2019},
url = {https://hdl.handle.net/10481/90079},
abstract = {In this paper, we develop a formula for spacelike surfaces in a 4-
dimensional Lorentzian space form which involves its mean curvature
vector  eld and the Gauss curvature of the induced metric and the
Gauss curvature of the second fundamental form associated to a non-
degenerate null normal section. By means of this formula, we stablish
several su cient conditions for compact spacelike surfaces with con-
stant Gauss curvature to have a null umbilical direction. As another
application, we give a new proof of the Liebmann rigidity theorem in
Euclidean, hemispherical and hyperbolic spaces, and in the De Sitter
spacetime.},
organization = {Spanish MINECO and ERDF
project MTM2013-47828-C2-1-P},
keywords = {Spacelike surface},
keywords = {Gauss curvature},
keywords = {Liebmann theorem},
title = {Spacelike surfaces which admit a nondegenerate null normal section in a Lorentzian space form},
doi = {10.1007/s40840-017-0557-x},
author = {Fuente Benito, Daniel de la and Palomo, Francisco J. and Romero Sarabia, Alfonso},
}