Algebraic Number Theory
Mathematics 605A: spring 2019

Professor: Rachel Pries, e-mail: rachelpries AT gmail DOT com;
web page:; office: Weber 205A.

Lecture: MWF 10:00-11:00, Engineering E206.

Prerequisite: Math 566 or permission of professor.

Homework and reading list: Detailed information on homework

Syllabus: Spring 2019 version or Official version

Course description: The study of number theory originated in ancient civilizations such as those of China and India and was developed in great depth in Europe in the 17th and 18th centuries. Number theory is known for having problems that are easy to state yet which can only be solved using deep and complicated structures. For example, it took 300 years to find a complete proof of Fermat's Last Theorem. Number theory is a subject that's intertwined with group theory, algebraic geometry, combinatorics, and complex analysis. It's become popular recently because of its applications to coding theory and cryptography.

Number theory is a vast subject. In this course, we will emphasize its algebraic aspects. Here are some of the themes of the course.

1) Reciprocity Laws: the quadratic reciprocity law (which has over 100 proofs) tells you whether or not a number is a square modulo a prime.

2) Ideal Factorization: this topic helps you measure the failure of unique factorization in rings of integers in number fields. The proof relies on Minkowski's theorem on the geometry of lattices in the plane.

3) Kummer theory, class groups, abelian extensions of number fields, applications to Fermat's last theorem.

4) Lattice based cryptosystems: these are the only cryptosystems currently immune to quantum attacks

Grading: The course grade will be based on 40% homework, 20% presentations, 40% final project.

References: See syllabus for references. Here are links to several on-line ones:
Milne: Algebraic Number Theory
Ogglier: Introduction to Algebraic Number Theory

We will also use the following books, which are freely available to CSU students through SpringerLink:

Marcus: Algebraic number fields
Ireland-Rosen: A Classical approach to modern number theory

Here is how to find the Springer Link books. step 1: go to the CSU library page CSU library page or (on-campus only?) .
step 2: in the almost everything box, type in keywords (e.g. Everest and Ward and Introduction and Number) and click the search icon.
step 3: click on the item, look for full text available, and download.

Other links: Stein: Brief Introduction to Classical and Adelic Algebraic Number Theory
Ash: A Course in Algebraic Number Theory

The project is an opportunity to learn more about a topic in number theory that interests you or will be relevant for your future graduate work. It gives us a chance to hear about important ideas which we will not have time to cover in class. It is also a good opportunity to develop more skill at writing and speaking on mathematics.

Help: Help is always available if you have trouble with homework or lecture material. If your classmates can't answer your question, come ask me! Office hours will be Wed 11-12, Thurs 1-2, or are available by appointment.