Math 530, Algebraic Number Theory

Spring 2026
Time and Place:
MWF 2:00-2:50pm in 336 Davenport Hall.

Instructor: William Chen
Email: wyc@illinois.edu
Office: 51 CAB (Computing Applications Building)
Office Hours: TENTATIVELY: Tuesdays 3-4pm, Thursdays 1-2pm

Textbook: James Milne, Algebraic Number Theory
Supplemental text: Marcus, Number Fields


Course Description

This is a graduate course in algebraic number theory. We will develop the theory of rings of integers of number fields. Some topics we will cover include: class groups and finiteness of the class number, Dirichlet’s unit theorem, cyclotomic extensions and applications to Fermat’s Last Theorem. Other potential topics include local fields, global fields, Dedekind zeta functions and the class number formula.


Course Policies

Grading: Your course grade will be based on homework (40%), one midterm exam (30%), and a final exam (30%)
Weekly homework: These will typically be due on Friday before class, to be submitted via gradescope. Late homework will not be accepted, but your lowest two homework scores will be dropped. Collaboration on homework is encouraged. However, you must write up your solutions individually and understand them completely.
In-class midterms:
One 50-minute exam to be held in our usual classroom.
Final exam:
TBA
Missed exams:
There will be no makeup exams. If your circumstances are truly extraordinary, I may excuse you from an exam, in which case your average will be determined by your other exams and homeworks.
Cheating: No.
Disabilities: Students with disabilities who require reasonable accommodations should see me as soon as possible. In particular, any accommodation on exams must be requested at least a week in advance and will require a letter from DRES.


Schedule

Jan 21 - Introduction. The Gaussian integers, primes as sums of 2 squares. [Notes]
Jan 23 - Rings of integers, norm and trace.

Mar 13 - Midterm Exam (tentative)
<Spring break>