NONLINEAR RENORMALIZATION-GROUP EQUATION FOR MATRIX MODELS

An exact renormalization group equation is derived for the free energy of matrix models. The renormalization group equation turns out to be nonlinear for matrix models, as opposed to vector models, where it is linear. An algorithm for determining the critical coupling constant an d the critical exponent is obtained. As concrete examples, one-matrix models with one and two coupling constants are analyzed and the exact values of the critical coupling constant and the associated critical e xponent are found.