THE HETEROTIC PREPOTENTIAL FROM 11 DIMENSIONS

We compactify M-theory in the Horava-Witten formulation on S-1/Z(2) x K3 x T-2. Focusing on the moduli-space of vector multiplets of the res ulting four-dimensional N = 2 theory, we determine the prepotential as an expansion in two dimensionless parameters which both scale as kapp a(2/3). We determine the prepotential completely to relative order kap pa(4/3) and compare the expression with the results obtained for the p erturbative string theories. We find complete agreement to relative or der kappa(4/3) between the strong and weak coupling regimes. The sourc es of higher order perturbative and non-perturbative corrections to th e prepotential are also briefly discussed from the M-theory perspectiv e.