Introduction

In this chapter we state, for later reference, a few basic results and definitions concerning free groups and the elements of the theory of unitary representations for discrete groups. The reader may go over these results quickly to become familiar with the notation and terminology, and return to this chapter later on, when the results are used in the succeeding chapters. Some of the more technical results of Sections 2 and 3 are actually used only occasionally, and should not be considered prerequisites to understand or appreciate most of these notes.