NEW CURVES FROM BRANES

We consider configurations of Neveu-Schwarz fivebranes, Dirichlet four branes and an orientifold sixplane in type IIA string theory. Upon lif ting the configuration to M-theory and proposing a description of how to include the effects of the orientifold sixplane we derive the curve s describing the Coulomb branch of N = 2 gauge theories with orthogona l and symplectic gauge groups, product gauge groups of the form circle times(i) SU(k(i)) circle times SO(N) and circle times(i) SU(k(i)) cir cle times Sp(N). We also propose new curves describing theories with u nitary gauge groups and matter in the symmetric or antisymmetric repre sentation. (C) 1998 Published by Elsevier Science B.V.