Perturbative and Non-Perturbative Results for $N=2$ Heterotic Strings

Abstract

In this paper we summarize our recent work about perturbative and non-perturbative effects in four-dimensional heterotic strings with $N=2$ space-time supersymmetry.Comment: Contribution for the Proceedings of the `Spring Workshop on String Theory, Gauge Theory and Quantum Gravity', Trieste, April 199