On the string interpretation of M(atrix) theory

It has been proposed recently that, in the framework of M(atrix) theory, N=8 supersymmetric U(N) Yang-Mills theory in 1+1 dimensions (SYM_{1+1}) gives rise to type IIA long string configurations. We point out that the quantum moduli space of SYM_{1+1} gives rise to two quantum numbers, which fit very well into the M(atrix) theory. The two quantum numbers become familiar if one switches to a IIB picture, where they represent configurations of D--strings and fundamental strings. We argue that, due to the $SL(2,Z)$ symmetry, of the IIB theory, such quantum numbers must represent configurations that are present also in the IIA framework.