An intrinsic characterization of a class of minimal surfaces in constant curvature manifolds

Let X be an iV-manifold of constant sectional curvature.A class of minimal surfaces in X, called exceptional minimal surfaces, will be defined in terms of the structure of their normal bundles.It will be shown that these surfaces can be characterized intrinsically in a way that generalizes the Ricci condition for minimal surfaces in Euclidean 3-space.It will also be shown that these surfaces are rigid when N is even and belong to 1-parameter families of isometric surfaces when N is odd.