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Elements of Number Theory 2003 ed. [Kietas viršelis]

4.23/5 (35 ratings by Goodreads)
  • Formatas: Hardback, 256 pages, aukštis x plotis: 234x156 mm, weight: 1240 g, XII, 256 p., 1 Hardback
  • Serija: Undergraduate Texts in Mathematics
  • Išleidimo metai: 13-Dec-2002
  • Leidėjas: Springer-Verlag New York Inc.
  • ISBN-10: 0387955879
  • ISBN-13: 9780387955872
Kitos knygos pagal šią temą:
  • Formatas: Hardback, 256 pages, aukštis x plotis: 234x156 mm, weight: 1240 g, XII, 256 p., 1 Hardback
  • Serija: Undergraduate Texts in Mathematics
  • Išleidimo metai: 13-Dec-2002
  • Leidėjas: Springer-Verlag New York Inc.
  • ISBN-10: 0387955879
  • ISBN-13: 9780387955872
Kitos knygos pagal šią temą:
This book is intended to complement my Elements oi Algebra, and it is similarly motivated by the problem of solving polynomial equations. However, it is independent of the algebra book, and probably easier. In Elements oi Algebra we sought solution by radicals, and this led to the concepts of fields and groups and their fusion in the celebrated theory of Galois. In the present book we seek integer solutions, and this leads to the concepts of rings and ideals which merge in the equally celebrated theory of ideals due to Kummer and Dedekind. Solving equations in integers is the central problem of number theory, so this book is truly a number theory book, with most of the results found in standard number theory courses. However, numbers are best understood through their algebraic structure, and the necessary algebraic concepts­ rings and ideals-have no better motivation than number theory. The first nontrivial examples of rings appear in the number theory of Euler and Gauss. The concept of ideal-today as routine in ring the­ ory as the concept of normal subgroup is in group theory-also emerged from number theory, and in quite heroic fashion. Faced with failure of unique prime factorization in the arithmetic of certain generalized "inte­ gers" , Kummer created in the 1840s a new kind of number to overcome the difficulty. He called them "ideal numbers" because he did not know exactly what they were, though he knew how they behaved.

Recenzijos

From the reviews:









"Solving equations in integers is the central problem of number theory, so this book is truly a number theory book, with most of the results found in standard number theory courses. The book is clearly written, well organized and is a very pleasurable reading: it is an excellent and very useful undergraduate textbook. However, thanks to the many examples and exercises, it is well suitable for independent study, as well." (Lįszlo Megyesi, Acta Scientiarum Mathematicarum, Vol. 71, 2005)



"In this carefully crafted undergraduate number theory text, Stillwell walks the reader through the main topics that belong in any introduction to number theory but he does so in a way that highlights the beguiling nature of number theory problems and keeps their rich history alive. This book has some additional features that will draw you to order it for your courses. Stillwell presents a compelling argument for studying the ancient and modern problems of number theory ." (Gwynneth G. H. Coogan, Mathematical Reviews, 2004 j)



"A solid systematic introduction to (algebraic) number theory which is truly elementary in the sense that a bright young undergraduate could make rapid unaided progress through this book. There are lots of goodies in the sidelines and the attention to clarity of writing and to pedagogic care give it a high rank amongst competing texts. Stillwells book makes a very positive contribution to the coherence of the subject, which adds to the satisfaction of studying it." (John Baylis, The Mathematical Gazette, Vol. 88 (512), 2004)



"Stillwell has taken very careful aim at his target audience and hit them squarely between the eyes. the author has done a wonderful job of conveying his obvious love of the subject to the reader. The author covers basic classical number theory. Each chapter opens with a substantial preview stating the central concepts whichare about to appear. In short, this book is a delight to read and is ideally suited to a beginning course in number theory." (Ralph H. Buchholz, The Australian Mathematical Society Gazette, Vol. 31 (1), 2004)



"The book is a concise introduction to number theory and some related algebra, with an emphasis on solving equations in integers. The historical development has been followed where it helps to motivate the introduction of new concepts, but modern proofs have been used where they are simpler, more natural, or more interesting. Also, this is the only elementary number theory book that includes significant applications of ideal theory." (Zentralblatt für Didaktik der Mathematik, February, 2003)



"The text would be suitable for the standard elementary number theory course. could serve as an introduction to algebraic number theory. has a number of unusual and attractive features. there is much in this book that would make it an appealing choice for a group of able mathematics majors. the book under review provides a valuable and original alternative to the many current texts on introductory number theory." (David W. Boyd, SIAM Review, Vol. 46 (2), 2004)

Preface vii
Natural numbers and integers
1(21)
Natural numbers
2(1)
Induction
3(2)
Integers
5(2)
Division with remainder
7(1)
Binary notation
8(3)
Diophantine equations
11(3)
The Diophantus chord method
14(3)
Gaussian integers
17(3)
Discussion
20(2)
The Euclidean algorithm
22(21)
The gcd by subtraction
22(2)
The gcd by division with remainder
24(2)
Linear representation of the gcd
26(2)
Primes and factorization
28(2)
Consequences of unique prime factorization
30(3)
Linear Diophantine equations
33(2)
The vector Euclidean algorithm
35(3)
The map of relatively prime pairs
38(2)
Discussion
40(3)
Congruence arithmetic
43(23)
Congruence mod n
44(1)
Congruence classes and their arithmetic
45(3)
Inverses mod p
48(3)
Fermat's little theorem
51(2)
Congruence theorems of Wilson and Lagrange
53(2)
Inverses mod k
55(2)
Quadratic Diophantine equations
57(2)
Primitive roots
59(3)
Existence of primitive roots
62(1)
Discussion
63(3)
The RSA cryptosystem
66(10)
Trapdoor functions
66(3)
Ingredients of RSA
69(1)
Exponentiation mod n
70(2)
RSA encryption and decryption
72(1)
Digital signatures
73(1)
Other computational issues
74(1)
Discussion
74(2)
The Pell equation
76(25)
Side and diagonal numbers
77(1)
The equation x2 -- 2y2 = 1
78(2)
The group of solutions
80(1)
The general Pell equation and Z(√n)
81(3)
The pigeonhole argument
84(3)
Quadratic forms
87(3)
The map of primitive vectors
90(5)
Periodicity in the map of x2 -- ny2
95(4)
Discussion
99(2)
The Gaussian integers
101(16)
Z[ i] and its norm
102(1)
Divisibility and primes in Z[ i] and Z
103(2)
Conjugates
105(2)
Division in Z[ i]
107(2)
Fermat's two square theorem
109(1)
Pythagorean triples
110(3)
*Primes of the form 4n + 1
113(2)
Discussion
115(2)
Quadratic integers
117(21)
The equation y3 = x2 + 2
118(1)
The division property in Z[ √-2]
119(2)
The gcd in Z[ √-2]
121(2)
Z[ √-3] and Z[ ζ3]
123(3)
*Rational solutions of x3 + y3 = z3 + w3
126(3)
*The prime √-3 in Z[ ζ3]
129(3)
*Fermat's last theorem for n = 3
132(4)
Discussion
136(2)
The four square theorem
138(20)
Real matrices and C
139(2)
Complex matrices and H
141(2)
The quaternion units
143(2)
Z[ i,j,k]
145(2)
The Hurwitz integers
147(2)
Conjugates
149(2)
A prime divisor property
151(1)
Proof of the four square theorem
152(2)
Discussion
154(4)
Quadratic reciprocity
158(23)
Primes x2 + y2, x2 + 2y2, and x2 + 3y2
159(2)
Statement of quadratic reciprocity
161(3)
Euler's criterion
164(3)
The value of (2/q)
167(2)
The story so far
169(2)
The Chinese remainder theorem
171(2)
The full Chinese remainder theorem
173(2)
Proof of quadratic reciprocity
175(3)
Discussion
178(3)
Rings
181(15)
The ring axioms
182(2)
Rings and fields
184(2)
Algebraic integers
186(3)
Quadratic fields and their integers
189(3)
Norm and units of quadratic fields
192(2)
Discussion
194(2)
Ideals
196(25)
Ideals and the gcd
197(2)
Ideals and divisibility in Z
199(3)
Principal ideal domains
202(3)
A nonprincipal ideal of Z[ √-3]
205(2)
A nonprincipal ideal of Z[ √-5]
207(2)
Ideals of imaginary quadratic fields as lattices
209(2)
Products and prime ideals
211(3)
Ideal prime factorization
214(3)
Discussion
217(4)
Prime ideals
221(18)
Ideals and congruence
222(2)
Prime and maximal ideals
224(1)
Prime ideals of imaginary quadratic fields
225(2)
Conjugate ideals
227(2)
Divisibility and containment
229(1)
Factorization of ideals
230(1)
Ideal classes
231(2)
Primes of the form x2 + 5y2
233(3)
Discussion
236(3)
Bibliography 239(6)
Index 245