Leon Takhtajan


Department of Mathematics
Stony Brook University

office: Math Tower 5-111
phone: (631) 632-8287
e-mail: leon.takhtajan@stonybrook.edu

MAT 536: Complex Analysis
Spring 2021
Schedule & Homework

Schedule


Dates Sections covered and assigned reading
Homework
Feb 4 & Feb 9 Complex numbers. Complex differentials and holomorphic functions, Cauchy-Riemann equations. Elementary theory of power series.
Ch.1 and Ch.2, §§1.1-1.4 and §§2.1-2.4.
HW 1 due: Feb 11
Feb 11 & Feb 16 The exponential and trigonometric functions. The logarithm. Holomorphic functions as mappings. Conformality.
Ch.2, § 2.5 and §§3.1-3.4, Ch.3, §§ 2.1-2.4.
HW 2 due: Feb 18
Feb 18 & Feb 23 Fractional linear transformations. Elementary conformal mappings. Complex integration.
Ch.3, §§3.1-3.5 and §§4.1-4.2, notes on Zhukovsky function and Ch. 4, §§1.1-1.3.
HW 3 due: Feb 23
Extra Credit due: Feb 25
Feb 25 & Mar 2 Complex integration. Goursat and Cauchy theorems. Cauchy integral formula and power series. Cauchy’s inequalities and consequences: Liouville's theorem and fundamental theorem of algebra.
Ch.4, §§1.1-1.5 and §2.3.

Presentation in class will differ from Ahlfors; I will simplify exposition in the textbook.
HW 4 due: Mar 4
  p. 108: 2, 3, 4, 5*, 6*, 7, 8 and p. 120: 1-3 in Ahlfors' book.
Mar 4 & Mar 9 Morera's theorem and Weierstrass theorem on uniform limits of holomorphic functions. Local properties of holomorphic functions. Index of a point with respect to a closed curve and strong form of Cauchy integral formula. Open mapping theorem and maximum modulus principle.
Ch.4, §§2.1-2.2, §§3.1-3.4 and Ch.5, §1.1.

Presentation in class will differ from Ahlfors. I will simplify some details in the textbook.
HW 5 due: Mar 11
Mar 11 & Mar 16 Maximum modulus principle and Schwarz lemma and conformal autmorphisms of the Riemann sphere, the complex plane and the unit disk.
Ch.4, §3.4.

HW 6 due: Mar 18
Mar 23 & Mar 25 The general form of Cauchy theorem. The residue theorem, the residue at infinity and sum of residues theorem.
Ch.4, §§4.1-4.6 and §5.1.

Presentation in class will differ from Ahlfors, we will prove a homotopy version of Cauchy theorem.
HW 7 due: Mar 25
Mar 30 & Apr. 1 The residue theorem cont. The argument principle and Rouche's theorem. Hurwitz theorem as application of Rouche theorem. Different proofs of Jensen's formula.
Shabat notes §3.3, Ahlfors Ch.4, §§5.1-5.2 and Ch.5, §3.1, and notes on the Blackboard.
HW 8 due: Apr 1
Apr 6 & Apr 8 Evaluation of definite integrals. Jordan lemma. Introduction to Euler gamma function and Riemann zeta function.
Shabat notes §3.3, Ahlfors Ch.4, §5.3 and Ch.5, §1.1.

Presentation in class will differ from Ahlfors, we will introduce the gamma function by the Mellin transform.
HW 9 due: Apr 8
Apr 13 & Apr 15 The Laurent series. Partial fractions and factorization, Mittag-Leffler and Weierstrass theorems.
Ch.5, §§1.1-1.3 and §§2.1-2.3.
HW 10 due: Apr 15
Apr 20 & Apr 22 Order and genus of entire function. Hadamard and Picard theorems (without a proof). Normal families, Montel theorem, the Riemann mapping theorem.
Ch.5, §§3.2 and §§5.1-5.5, Ch.6, §1.1. & Ch.8, §3.1.

Our exposition will be somewhat different from Ahlfors: we will do only what is necessary for the proof of the Riemann mapping theorem.
HW 11 due: Apr 23
Apr 27 & Apr 29 The Riemann mapping theorem: Riemann's original proof. Boundary behavior. Schwarz reflection principle. Modular λ-function and Picard theorem.
Ch.6, §§1.2.-1.4.
HW 12 due: Apr 30
May 4 & May 6 Harmonic functions. Functions with mean-value property. Harnack's principle. The Dirichlet problem and subharmonic functions.
Ch.4, §§6.1.-6.5, Ch.6, §§3.1-3.2 and §§4.1-4.2.
HW 13 due: May 7