RENDICONTI DELL'ISTITUTO DI MATEMATICA DELL'UNIVERSITAÌ€ DI TRIESTE
Abstract
Maxwell theory may be regarded as a prototype of gauge theory and generalized to nonabelian gauge theory. We briefly sketch the history of the gauge theories, from Maxwell to Yang-Mills theory, and the identification of gauge fields with connections on fibre bundles. We introduce the notion of instanton and consider the moduli spaces of such objects. Finally, we discuss some modern techniques for studying the topology of these moduli spaces.