NONPERTURBATIVE RESULTS ON THE POINT PARTICLE LIMIT OF N=2 HETEROTIC STRING COMPACTIFICATIONS

Using heterotic/type II string duality, we obtain exact non-perturbati ve results for the point particle limit (alpha' --> 0) of some particu lar four dimensional, N = 2 supersymmetric compactifications of hetero tic strings. This allows us to recover recent exact non-perturbative r esults on N = 2 gauge theory directly from tree-level type II string t heory, which provides a highly non-trivial, quantitative check on the proposed string duality. We also investigate to what extent the releva nt singular limits of Calabi-Yau manifolds are related to the Riemann surfaces that underlie rigid N = 2 gauge theory.