Minimal and harmonic unit vector fields in G(2)(Cm+2) and its dual space

The complex two-plane Grassmannian G(2)(Cm+2) carries a Kahler structure J and also a quaternionic Kahler structure J. For m greater than or equal to 3 we consider the classes of connected real hypersurfaces (M, g) with norma l bundle M-perpendicular to such that J(M-perpendicular to) and J(M-perpend icular to) are invariant under the action of the shape operator. We prove t hat the corresponding unit Hopf vector herds on these hypersurfaces always define minimal immersions of (M, g), and harmonic maps from (M,g), into the unit tangent sphere bundle (T1M,g(s)) with Sasaki metric gs. The radial un it vector fields corresponding to the tubular hypersurfaces are also minima l and harmonic. Similar results hold for the dual space G(2)(Cm+2)*. 1991 M athematics Subject Classification: 53C20, 53C25, 53C35, 53C40, 53C42, 53C55 , 58E20.