Lightlike hypersurfaces of indefinite Sasakian manifolds (Q1428343)

This paper is mainly covered by section 3: A brief review of light-like immersions, and section 4: Light-like hypersurfaces. There, the Gauss and Weingarten formulas are adapted to apply to indefinite metrics, especially here for indefinite Sasakian manifolds. The authors prove that there are no totally umbilical light-like hypersurfaces of indefinite Sasakian space forms with \(c \neq 1\). Here, \(c\) denotes the value of the sectional curvature.