How to Prove It: A Structured ApproachMany students have trouble the first time they take a mathematics course in which proofs play a significant role. This new edition of Velleman's successful text will prepare students to make the transition from solving problems to proving theorems by teaching them the techniques needed to read and write proofs. The book begins with the basic concepts of logic and set theory, to familiarize students with the language of mathematics and how it is interpreted. These concepts are used as the basis for a step-by-step breakdown of the most important techniques used in constructing proofs. The author shows how complex proofs are built up from these smaller steps, using detailed 'scratch work' sections to expose the machinery of proofs about the natural numbers, relations, functions, and infinite sets. To give students the opportunity to construct their own proofs, this new edition contains over 200 new exercises, selected solutions, and an introduction to Proof Designer software. No background beyond standard high school mathematics is assumed. This book will be useful to anyone interested in logic and proofs: computer scientists, philosophers, linguists, and of course mathematicians. |
Contents
Introduction | 1 |
Sentential Logic | 8 |
12 Truth Tables | 14 |
13 Variables and Sets | 26 |
14 Operations on Sets | 34 |
15 The Conditional and Biconditional Connectives | 43 |
Quantificational Logic | 55 |
22 Equivalences Involving Quantifiers | 64 |
45 Closures | 202 |
46 Equivalence Relations | 213 |
Functions | 226 |
52 Onetoone and Onto | 236 |
53 Inverses of Functions | 245 |
A Research Project | 255 |
Mathematical Induction | 260 |
62 More Examples | 267 |
23 More Operations on Sets | 73 |
Proofs | 84 |
32 Proofs Involving Negations and Conditionals | 95 |
33 Proofs Involving Quantifiers | 108 |
34 Proofs Involving Conjunctions and Biconditionals | 124 |
35 Proofs Involving Disjunctions | 136 |
36 Existence and Uniqueness Proofs | 146 |
37 More Examples of Proofs | 155 |
Relations | 163 |
42 Relations | 171 |
43 More About Relations | 180 |
44 Ordering Relations | 189 |
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Common terms and phrases
a₁ An+1 Analyze the logical arbitrary element assume assumption choose conclude countable counterexample defined definition DeMorgan's law disjoint element of F equation equivalence classes equivalence relation example exercise existential F and G fact false family of sets Figure finite following proof free variables function f ƒ is one-to-one Hint Induction step inductive hypothesis Let f logical forms mathematical induction mathematicians means minimal element modus ponens natural number negation law notation ordered pairs P(xo partial order plug positive integer prime number proof by contradiction Proof Designer proof strategies prove a goal PV Q quantifier R₁ real number recursive reexpress reflexive closure Scratch Similarly smallest element Solution Theorem stand statement P(x strong induction subset Suppose F symbols symmetric closure total order transitive closure truth set truth table Uiel Venn diagrams Vx(x words write