Table of Contents
Preface to the Second Edition v
Preface to the First Edition vii
List of Figures ix
List of Tables xi
1 Logic and Proofs 1
1.1 Introduction 1
1.2 Statement, Connectives and Truth Tables 2
1.3 Relations between Statements 5
1.4 Quantifiers 6
1.5 Methods of Proof 9
1.6 Exercises 11
2 Set Theory 13
2.1 Initial Concepts 13
2.2 Relations between Sets 15
2.3 Operations Defined on Sets -or New Sets from Old 16
2.4 Exercises 19
3 Cartesian Products, Relations, Maps and Binary Operations 23
3.1 Introduction 23
3.2 Cartesian Product 23
3.3 Maps 29
3.4 Binary Operations 37
3.5 Exercises 51
4 The Integers 55
4.1 Introduction 55
4.2 Elementary Properties 55
4.3 Divisibility 61
4.4 The Fundamental Theorem of Arithmetic 67
4.5 Congruence Modulo n and the Algebraic System (Zn,+, ) 69
4.6 Linear Congruences in Z and Linear Equations in Zn 75
4.7 Exercises 80
5 Groups 85
5.1 Introduction 85
5.2 Definitions and Elementary Properties 86
5.3 Alternative Axioms for Groups 93
5.4 Subgroups 96
5.5 Cyclic Groups 109
5.6 Exercises 113
6 Further Properties of Groups 117
6.1 Introduction 117
6.2 Cosets 117
6.3 Isomorphisms and Homomorphisms 123
6.4 Normal Subgroups and Factor Groups 134
6.5 Direct Product of Groups 145
6.6 Exercises 152
7 The Symmetric Groups 157
7.1 Introduction 157
7.2 The Cayley Representation Theorem 157
7.3 Permutations as Products of Disjoint Cycles 159
7.4 Even and Odd Permutations o 166
7.5 The Simplicity of An176
7.6 Exercises 180
8 Rings, Integral Domains and Fields 183
8.1 Rings 183
8.2 Ring Homomorphisms, Ring Isomorphisms, and Ideals 192
8.3 Isomorphism Theorems 198
8.4 Direct Product and Direct Sum of Rings 199
8.5 Principal Ideal Domains and Unique Factorization Domains 207
8.6 Embedding an Integral Domain in a Field 211
8.7 The Characteristic, of an Integral Domain 214
8.8 Exercises 217
9 Polynomial Rings 225
9.1 Introduction 225
9.2 The Ring of Power Series with Coefficients in a Commutative Unital Ring R 226
9.3 The Ring of Polynomials with Coefficients in a Commutative Unital Ring 228
9.4 The Division Algorithm and Applications 234
9.5 Irreducibility and Factorization of Polynomials 240
9.6 Polynomials over Q 245
9.7 Irreducible Polynomials over R and C 250
9.8 Quotient Rings of the Form F[x]/(f), F a Field 253
9.9 Exercises 259
10 Field Extensions 263
10.1 Introduction 263
10.2 Definitions and Elementary Results 263
10.3 Algebraic and Transcendental Elements 267
10.4 Algebraic Extensions 270
10.5 Finite Fields 276
10.6 Exercises 284
11 Latin Squares and Magic Squares 289
11.1 Introduction 289
11.2 Magic Squares 294
11.3 Exercises 296
12 Group Actions, the Class Equation, and the Sylow Theorems 299
12.1 Group Actions 299
12.2 The Class Equation of a Finite Group 303
12.3 The Sylow Theorems 304
12.4 Applications of the Sylow Theorems 307
12.5 Exercises 322
13 Finitely Generated Abelian Groups 327
13.1 Introduction and Preliminary Results 327
13.2 Direct Sum of Abelian Groups 330
13.3 Free Abelian Groups 332
13.4 Finite Abelian Groups 336
13.5 The Structure of the Group of Units of Zn 340
13.6 Exercises 345
14 Semigroups and Automata 347
14.1 Introduction 347
14.2 Semigroups 347
14.3 The Semigroup of Relations on a Set 364
14.4 Green's Relations 367
14.5 Semigroup Actions 377
14.6 Automata Theory 385
14.7 Exercises 399
15 Isometries 407
15.1 Isometrics of Rn 407
15.2 Finite Subgroups of the Isometry Group of Rn 412
15.3 The Classification of the Finite Subgroups of SO(3) 416
15.4 The Platonic Solids 421
15.5 Exercises 428
16 Pólya-Burnside Enumeration 431
16.1 Introduction 431
16.2 A Theorem of Pólya 434
16.3 Enumeration Examples 436
16.4 Exercises 440
17 Group Codes 445
17.1 Introduction 445
17.2 Group Codes 451
17.3 Construction of Group Codes 454
17.4 At the Receiving End 457
17.5 Nearest Neighbor Decoding for Group Codes 457
17.6 Hamming Codes 460
17.7 Exercise 463
18 Polynomial Codes 467
18.1 Definitions and Elementary Results 467
18.2 BCH Codes 472
18.3 Decoding for a BCH Code 477
15.1 Exercises 482
Appendix A Rational, Real, and Complex Numbers 485
A.1 Introduction 485
A.2 The Order Relation on the Real Number System 486
A.3 Decimal Representation of Rational Numbers 489
A.4 Complex Numbers 492
A.5 The Polar Form of a Complex Number 495
A.6 Exercises 499
Appendix B Linear Algebra 503
B.1 Vector Spaces 503
B.2 Linear Transformations 513
B.3 Determinants 525
B.4 Eigenvalues and Eigenvectors 536
B.5 Exercises 541
Index 545