Introduction

In this introductory chapter, we discuss ideas and results from combinatorics (especially graph theory) and algebra (fields and vector spaces) that will be used later. Analytical tools, as well as the elements of polynomial theory, which are sometimes used in this book, are not specifically mentioned or defined, believing, as we do, that the reader will be familiar with them. In accordance with the goals of this book, vector spaces are described in a very limited way. The emphasis of this book is on matrix theory and computation, and not on linear algebra in general.