ON SURFACES IN THE 3-DIMENSIONAL LORENTZ-MINKOWSKI SPACE

Let M(s)2 be a surface in the 3-dimensional Lorentz-Minkowski space L3 and denote by H its mean curvature vector field. This paper locally classifies those surfaces verifying the condition DELTA-H = lambda-H, where lambda is a real constant. The classification is done by proving that M(s)2 has zero mean curvature everywhere or it is isoparametric, i.e., its shape operator has constant characteristic polynomial.