D-Brane Realization of N = 2 Super Yang-Mills Theory in Four Dimensions

We develop and study a D-brane realization of 4D N = 2 super Yang-Mills theory. It is a type IIB string theory compactified on R × K3 and containing parallel 7-branes. It can also be regarded as a subsector of Vafa’s F-theory compactified on K3 × K3 and is thus dual to the heterotic string on K3× T . We show that the one-loop prepotential in this gauge theory is exactly equal to the interaction produced by classical closed string exchange. A monopole configuration corresponds to an open Dirichlet 5-brane wrapping around K3 with ends attached to two 7-branes.