WHY MATRIX-THEORY IS HARD

Recently Sen and Seiberg gave a prescription for constructing the matr ix theory in any superstring background. We use their prescription to test the finite N matrix theory conjecture on an ALE space. Based on o ur earlier work with Shenker, we find a sharper discrepancy between ma trix theory computation and supergravity prediction. We discuss subtle ties in the light-front quantization which may lead to a resolution to the discrepancy. (C) 1998 Published by Elsevier Science B.V. All righ ts reserved.