摘要
Let M be a surface in Euclidean space R3.It is known that when the curvature K of M is a constant, M is locally isometric to either a sphere or a plane, and was generalized by many authors. Thomas proved that an Einstein hypersurface in the （n+1）-dimensional Euclidean space Rn+1（n≥3） is locally a sphere. S.Y.
