A Simons type formula for surfaces with parallel mean curvature

Abstract

We prove a Simons type equation for non-minimal surfaces with parallel mean curvature vector (pmc surfaces) in $M^n(c)\times \mathbb{R}$, where $M^n(c)$ is an $n$-dimensional space form. Then, we use this equation in order to characterize complete non-minimal pmc surfaces with non-negative Gaussian curvature.

This paper has been withdrawn by the authors because equation 3.13 (the Simons type equation) is a particular case of formula 2.8 in [S.-Y. Cheng and S.-T. Yau, Hypersurfaces with constant scalar curvature, Math. Ann. 225(1977), 195--204