Math 525: Algebraic Number Theory

This is the information page for Math 525, Fall 2002.

Text: A Classical Introduction to Modern Number Theory, 2nd edition, by K. Ireland and M. Rosen. Supplemental material on algebraic number fields will be drawn from "Algebraic Number Theory" by Stewart and Tall.

I do not expect to cover the complete text in a single semester. Instead I plan to discuss Chapters 5-12, with supplemental material on algebraic number fields as time permits. Many of the standard results in algebraic number theory can also be regarded as results in algebraic K-theory, so algebraic topologists may be interested in this course.

Homework

Assignment Chapter Problems Date Due
1 5 1, 6, 10, 14, 16, 22, 23, 24, 25 September 10
2 6 1,2,3,4,5,6,7,23 September 19
3 6 11, 15, 18
7 6, 7, 8, 18, 21, 22, 23 September 26
4 8 3, 4, 5, 9, 11, 12 Thursday, October 10
5 8 13, 16, 17, 18, 27 Thursday, October 17
6 9 2, 3, 4, 5, 6 [(a) only], 7 [-7-3w only], 8 [143 only], 13, 14 Tuesday, October 29
7 9 27, 28, 29, 30, 33, 45 Thursday, November 7
8 handout (8 problems) Tuesday, November 26
9 handout (7 problems) Thursday, December 12

Tests

Test Material Location Date and Time
1 Chapters 5-7 LN 2205 October 2, 7-9 PM
2 Chapters 8-9 LN2205 November 13, 7-9PM
3
Final Exam Entire Course SW325 December 17, 2-4 PM

What to know for the final exam:

  1. Statement, proof, and applications of quadratic reciprocity. The proof to know is the second one, which is really the same as the third one. You need not learn the details of the first proof.
  2. Basic properties of finite fields, Gauss and Jacobi sums. For example, you may ignore Jacobi sums involving more than 2 characters.
  3. Properties of the rings Z[w] and Z[i]: units, primes, quotient fields, and norms.
  4. Statement and application of cubic and biquadratic reciprocity. Of course this includes the definition of the relevant reside symbols. You need not know the proofs of these results.
  5. General facts about the ring of integers in an number field. For example, you should be able to prove that the ring of integers, considered as an additive abelian group, is free of rank equal to the degree of the extension.
  6. Quadratic and cyclotomic fields: know what the rings of integers are, and why. You need not memorize the discussion of the ring of integers in cyclotomic fields, but you should be able to, for example, compute the discriminant.
  7. Unique factorization of ideals: Know the result and its applications. You need not learn the 9-step proof.
  8. Applications to solving equations when unique factorization is known. For example, assuming unique factorization in the relevant ring, you should be able to show that the only positive integer solutions of y^2 + 4 = x^3 are x = 5, y = 11 and x = 2, y = 2. (This is a fairly time-consuming problem, and were it on the test, it would be packaged in parts, with hints.)
  9. You need not know the statement, proof, or applications of the Eisenstein Reciprocity Law.
Note that the emphasis in the exam will be on the material since the second test.