Complex Analysis I

Fall Semester 2026



Instructor: Matt Kerr
Office: Cupples I, Room 114
e-mail: matkerr [at] math.wustl.edu
Office Hours: Mon/Wed 1-2

Course Outline:
  • Basics on complex functions and topology
  • Formal and convergent power series
  • Conformal maps and fractional linear transformations
  • Complex integration and Cauchy's theorem
  • Properties of analytic and harmonic functions
This is the first half of the year-long Ph.D. qualifying course in complex variables. This semester we will cover the first four to five chapters of the classic book by Ahlfors (3rd edition), with various embellishments from other points of view, especially the systematic use of power and Laurent series as in the books by Cartan and Lang (see below). The central result is the homology version of Cauchy's theorem.

The second semester course (Math 5122) will finish Ahlfors, covering (among other things) elliptic functions, the Riemann mapping theorem, the big Picard theorem, and the prime number theorem. Additional topics of study will include modular forms and several complex variables.

Prerequisites (for undergraduates): Math 4111, 4171, and 4181, or permission of instructor.

Class Schedule:

Lectures are on Monday, Wednesday and Friday from 12PM--12:50PM in Cupples II Room L015. First class is Monday Aug. 24 and last class is Monday Dec. 7, with holidays on Monday Sep. 7, Monday Oct. 5, and Wed/Fri Nov. 25/27.

Midterm Exam 1: Friday Oct. 16 (in class)
Midterm Exam 2: Monday Nov. 16 (in class)
Final Exam: Wednesday Dec. 16, 10:30AM--12:30PM, in the same classroom.

Assignments:

There will be a weekly homework due on Thursday by 11:59PM (starting the second week), to be turned in via Gradescope. I am available for help in office hours. (Regarding late homework, see the Grading Policy below.) The assignments will be distributed through Gradescope, and solutions posted on Canvas. Make sure you can do the problems I don't assign.

HW 1: (I.A) #3, 4; (I.B) #1, 2, 5

Grader: Calvin Reedy, c.m.reedy [at] wustl.edu

Lecture Notes:

Will be posted here on the day of the lecture. The hope is that this makes taking notes optional.

I. Holomorphic functions
A. Complex numbers
B. Complex functions
C. Topology of the complex plane
D. Power series

Books:

Lars Ahlfors, Complex Analysis (3rd Ed.); McGraw-Hill

is the recommended textbook, which means I will follow it at least half the time and some of the problems I assign will come from it. Buy, check out, or borrow a copy.

If you would like to read more adventurously than Ahlfors and/or my lecture notes, here are some suggestions. First, there are many other excellent standard texts, including

John B. Conway, Functions of One Complex Variable; Springer

Robert Greene and Steven Krantz, Function Theory of One Complex Variable; AMS

and the second half of

Walter Rudin, Real and Complex Analysis (3rd Ed.); McGraw-Hill.

For a point of view based in formal and convergent power series (convenient for locally computing composition inverses and solutions of differential equations) you can consult

Henri Cartan, Elementary Theory of Analytic Functions of One and Several Complex Variables; Addison-Wesley

Serge Lang, Complex Analysis (3rd Ed.); Springer.

For a view toward several complex variables there is

Raghavan Narasimhan and Yves Nievergelt, Complex Analysis in One Variable; Birkhauser ;

and the beautiful expository monograph

Steven Krantz, Complex Analysis: the Geometric Viewpoint; MAA

treats theorems in complex analysis through the prism of differential geometry. Finally,

Harvey Cohn, Conformal Mapping on Riemann Surfaces; Dover

leads (with lots of beautiful pictures and physical intuition) into Riemann surfaces and complex algebraic geometry.

A copy of each of these books has been placed on the reserve shelf behind the help/front desk of Olin Library. If you go to the front desk and ask for one of the books, you can check it out for use in the library for 3 hours.
Grading Policy:

Your final grade for the semester is determined as follows: HW 20%, Midterm 1 20%, Midterm 2 20%, final exam 40%. I will drop the lowest two grades you receive on homework. You may not use AI in any stage of preparation of your homework. On the other hand, I would encourage you to discuss problems with me and with other students.

Homework and examination grades will be regularly updated on Canvas.

Grades are typically curved in a course like this but will never be less than the following scale:

A+ A A- B+ B B- C+ C C- D F
TBA 90+ [85,90) [80,85) [75,80) [70,75) [65,70) [60,65) [55,60) [50,55) [0,50)

If you are a graduate student, a letter grade of B is required to pass; if you are an undergraduate taking this class Pass/Fail, you must earn a C- to pass.

All work submitted under your name is expected to be your own; please make sure to document any ideas that come from another source.