AN EXACT SOLUTION TO THE O(26) SIGMA-MODEL COUPLED TO 2D QUANTUM-GRAVITY

By a mapping to the bosonic string theory, we present an exact solutio n to the O(26) sigma model coupled to 2D quantum gravity. In particula r, we obtain the exact gravitational dressing to the various matter op erators classified by the irreducible representations of O(26). We als o derive the exact form of the gravitationally, modified beta function for the original coupling constant e2. The relation between our exact solution and the asymptotic solution given by Klebanov, Kogan, and Po lyakov is discussed in various aspects.