PREFACE ix ACKNOWLEDGMENTS xvii
NOTATION USED IN THE TEXT xix
A SKETCH OF THE HISTORY OF ALGEBRA TO 1929 xxiii
0 Preliminaries 1
0.1 Proofs / 1
0.2 Sets / 5
0.3 Mappings / 9
0.4 Equivalences / 17
1 Integers and Permutations 23
1.1 Induction / 24
1.2 Divisors and Prime Factorization / 32
1.3 Integers Modulo n / 42
1.4 Permutations / 53
1.5 An Application to Cryptography / 67
2 Groups 69
2.1 Binary Operations / 70
2.2 Groups / 76
2.3 Subgroups / 86
2.4 Cyclic Groups and the Order of an Element / 90
2.5 Homomorphisms and Isomorphisms / 99
2.6 Cosets and Lagrange's Theorem / 108
2.7 Groups of Motions and Symmetries / 117
2.8 Normal Subgroups / 122
2.9 Factor Groups / 131
2.10 The Isomorphism Theorem / 137
2.11 An Application to Binary Linear Codes / 143
3 Rings 159
3.1 Examples and Basic Properties / 160
3.2 Integral Domains and Fields / 171
3.3 Ideals and Factor Rings / 180
3.4 Homomorphisms / 189
3.5 Ordered Integral Domains / 199
4 Polynomials 202
4.1 Polynomials / 203
4.2 Factorization of Polynomials Over a Field / 214
4.3 Factor Rings of Polynomials Over a Field / 227
4.4 Partial Fractions / 236
4.5 Symmetric Polynomials / 239
4.6 Formal Construction of Polynomials / 248
5 Factorization in Integral Domains 251
5.1 Irreducibles and Unique Factorization / 252
5.2 Principal Ideal Domains / 264
6 Fields 274
6.1 Vector Spaces / 275
6.2 Algebraic Extensions / 283
6.3 Splitting Fields / 291
6.4 Finite Fields / 298
6.5 Geometric Constructions / 304
6.6 The Fundamental Theorem of Algebra / 308
6.7 An Application to Cyclic and BCH Codes / 310
7 Modules over Principal Ideal Domains 324
7.1 Modules / 324
7.2 Modules Over a PID / 335
8 p-Groups and the Sylow Theorems 349
8.1 Products and Factors / 350
8.2 Cauchy's Theorem / 357
8.3 Group Actions / 364
8.4 The Sylow Theorems / 371
8.5 Semidirect Products / 379
8.6 An Application to Combinatorics / 382
9 Series of Subgroups 388
9.1 The Jordan-H¨older Theorem / 389
9.2 Solvable Groups / 395
9.3 Nilpotent Groups / 401
10 Galois Theory 412
10.1 Galois Groups and Separability / 413
10.2 The Main Theorem of Galois Theory / 422
10.3 Insolvability of Polynomials / 434
10.4 Cyclotomic Polynomials and Wedderburn's Theorem / 442
11 Finiteness Conditions for Rings and Modules 447
11.1 Wedderburn's Theorem / 448
11.2 The Wedderburn-Artin Theorem / 457
Appendices 471
Appendix A Complex Numbers / 471
Appendix B Matrix Algebra / 478
Appendix C Zorn's Lemma / 486
Appendix D Proof of the Recursion Theorem / 490
BIBLIOGRAPHY 492
SELECTED ANSWERS 495
INDEX 523
