ORIENTIFOLD 4-PLANE IN BRANE CONFIGURATIONS AND N=4 USP(2N(C)) AND SO(N-C) THEORY

We consider brane configurations in elliptic models representing softl y broken N = 4 USp (2N(c)) and SO(N-c) theory. We generalize the notio n of the O4-plane, so that it is compatible with the symmetry in the c overing space of the elliptic models. By using this notion of the O4 p lane, we find the curve for softly broken N = 4 USp(2N(c)) and that fo r SO(N-c) theory as infinite series expansions. For the USp case, we c an present the expansion as a polynomial. (C) 1998 Elsevier Science B. V.