An Integral Inequality for Compact Spacelike Hypersurfaces in De Sitter Space and Applications to the Case of Constant Mean Curvature Sebastian Montiel Indiana University Mathematics Journal 1988 text pdf 10.1512/iumj.1988.37.37045 10.1512/iumj.1988.37.37045 en Indiana Univ. Math. J. 37 (1988) 909 - 917 state-of-the-art mathematics http://iumj.org/access/