INTERACTION OF F-STRING AND D-STRING IN THE MATRIX MODEL

We study a configuration of a parallel F-(fundamental) and D-string in IIB string theory by considering its T-dual configuration in the matr ix model description of M-theory. We show that certain nonperturbative features of string theory such as O (e(-1/gs)) effects due to soliton loops, the existence of bound state (1,1) strings and manifest S-dual ity, can be seen in matrix models. We discuss certain subtleties that arise in the large-N limit when membranes are wrapped around compact d imensions.