Internal Holonomy Groups of Yang-Mills Fields

Classical Yang-Mills potentials define a Lie group, the internal holonomy group, which is analogous to the ordinary holonomy group defined by the Christoffel symbols in general relativity. The internal holonomy group is an important tool for the dissection and study of the Yang-Mills equations and of local gauge theory in general. A number of theorems on internal holonomy groups is presented, together with some applications.