But we do believe that our readers may find it helpful to have available to them, in easily digestible form, some suggestions as to how to raise their expectations of success in tackling a mathematical exercise. That is our main purpose in including Chapter 9. We would like to say a few words here about our notation and terminology and our expository conventions. Second, we adopt certain conventions and practices in this text to help you to appreciate the significance of the material. Third, despite our informal approach, we always introduce you to the correct mathematical term.
Corollaries are less important assertions which follow fairly quickly from the previous theorem.
Conjectures , on the other hand, are hypotheses which may or may not be true, but which we have some rational grounds for believing. It may also be helpful to say a word about the use of the letters of our alphabet, or the Greek alphabet, to represent mathematical concepts like numbers, functions, points, angles, and so on. By the same token we cannot reserve, in the strict sense, any letter throughout an article, much less a book, so that it always ref6rs to the same concept. As a final remark in this Preface, it is a pleasure to acknowledge the essential assistance given to us by Kent Pedersen in assembling the Index. Now you're ready to start, and we hope you have an interesting and enjoyable journey through our text.