Resumen de The mean curvature of the second fundamental form

Stephan Haesen, Steven Verpoort, Leopold Verstraelen

• The critical points of the area functional of the second fundamental form of Riemannian surfaces in three-dimensional semi-Riemannian manifolds are determined. They are characterized by the vanishing of a scalar function, which will be called the mean curvature of the second fundamental form. A property which involves this new mean curvature is distinctive for totally umbilical surfaces