# Introduction to proofs, CSI Math 505, Spring 2017

I shall be teaching a new course Introduction to Proofs at the CUNY College of Staten Island this semester.

The course is intended for aspiring mathematics students who are learning—perhaps for the first time in a serious way—how to write mathematical proofs. I think of it as a kind of mathematical coming-of-age course, for students on the cusp, maturing into mathematicians, who aspire to communicate mathematical truths to other mathematicians in the currency of mathematics, which is: proof.

I hope to help them learn how a mathematician makes an argument in order to establish a mathematical truth.

I have written a new book specifically for the course, Proof and the art of mathematical reasoning, which I hope will be available before too long. The text will be suitable for any kind of introduction-to-proofs or transition-to-proofs course at the undergraduate level, with a variety of elementary proofs from a broad swath of mathematical topics. I shall post some excerpts later, to give you an idea of the nature of the book, but for now let me simply list the current table of contents. The book begins in chapter one with the proof that $\sqrt{2}$ is irrational. The epilogue contains a variety of logic puzzles in epistemic logic.

Preface 5
A note to the instructor 11
Chapter 1. Begin with a classic 13
Chapter 2. Multiple proofs 21
Chapter 3. Number theory and the primes 27
Chapter 4. Mathematical Induction 37
Chapter 5. Discrete mathematics and finite combinatorics 45
Chapter 6. Pick’s theorem: a case study in Pólya’s advice 57
Chapter 7. Visual proofs 67
Chapter 8. Geometry and lattice-point regular polygons 77
Chapter 9. Relations 85
Chapter 10. Graph theory 95
Chapter 11. Order theory 105
Chapter 12. Theory of games 111
Chapter 13. Set theory 129
Chapter 14. Real analysis 139
Epilogue 153
Bibliography 171