Math 113: Complex Function Theory

Spring 2013, TuTh 1-2:30, Science Center 309

My name: Andrew Cotton-Clay (please call me Andy)

Office: Science Center 527

Office Hours: Wed 1:15-2:15 and Thu 2:45-3:45 or by appointment.

E-mail: acotton at math

Course Assistants:
Felix Wong, fwong at college
Anirudha Balasubramanian, balasubramanian at college

CA Sections and Office Hours:
Felix: Section Th 4-5, location TBA; Office hours W 9-11 PM in Winthrop D Hall
Anirudha: TBA

Syllabus: Math 113 Syllabus

Course iSite: Math 113 iSite (Look for Felix's lecture notes here!)


Problem Sets:

Due Feb 7
Due Feb 14
Due Feb 21
Due Feb 28
Due Mar 7
Midterm Practice Problems (solutions)
The midterm will cover chapters 1-9 of the textbook [BN], excluding material we did not cover (e.g. only Morera's theorem from chapter 7). The set of practice problems is representative of the sort of problem that will appear on the midterm, but is longer by a problem or two.
Due Mar 28
Due Apr 4
Due Apr 11 or 16
Due Apr 18 or 23
Due Apr 25 or 30


Lectures:

Tue 1/29: BN 1.1-2. Algebra and geometry of the complex numbers. Roots of unity.
Thu 1/31: BN 1.3-4, 2.2-3. Stereographic projection exchanges circles and circles & lines. Inversion and coordinates at infinity on the Riemann sphere. Radius of convergence for power series and derivatives of power series.
Tue 2/5: Uniqueness properties for power series (remainder of BN 2.3). Cauchy-Riemann equations; proof that these plus continuous partials implies holomorphic: see BN 3.1. CR equations equivalent to derivative matrix commutes with rotation by pi/2. Holomorphic polynomials in x and y are precisely those which can be written in terms of z and z-bar with no z-bars: BN 2.1.
Thu 2/7: Exponential, trigonometric, and logarithm functions of a complex variable: see BN 3.2 for the first two and BN 8.2 (excluding the theorem) for the logarithm. Line integrals of complex functions and the fundamental theorem of such: see BN 4.1.
Tue 2/12: BN 4.2 and 5.1: Closed curve theorem, Cauchy's integral theorem, and proof that holomorphic functions on a disk are analytic with radius of convergence at least the radius of the disk (BN 6.1-2).
Thu 2/14: BN 5.2 and beginning of 6.3. Example of integral from 0 to infinity of (sin x)/x via closed curve theorem. Liouville theorem and generalizations, fundamental theorem of algebra, uniqueness theorem for holomorphic functions, and mean value theorem.
Tue 2/19: BN 6.3 and beginning of 7.1: Maximum and minimum modulus theorems via mean value theorem and via power series. Open mapping theorem. BN 1.4 and 8.1: Topological details for the general closed curve theorem (different method than book).
Thu 2/21: More topological details for general closed curve theorem. Definition of connected; proof it's the same as piecewise linearly connected for open sets in C. Piecewise linear model for the first homology of C in terms of formal sums of triangles, edges, and points. BN 7.2: Morera's theorem, limits of holomorphic functions, and Riemann Zeta function is holomorphic for Re(z)>1.
Tue 2/26: Open sets on Riemann sphere are sets whose intersection with C is open, plus, if the set includes infinity, it includes a neighborhood of infinity: i.e. all z with |z|>R, for some R. Conclusion of theorem that the closed curve theorem applies to open sets U in C such that C-hat minus U is connected. BN 7.2: More applications of Morera's theorem: the Gamma function is holomorphic for Re(z)>0, and removal of singularities. BN 9.1: Removable singularities, poles, and essential singularities. Casorati-Weierstrass theorem. BN 9.2: Laurent expansions: definition and convergence.
Thu 2/28: BN 9.2: Laurent expansions and proof they exist for functions defined in an annulus. Definition of meromorphic functions, and their nature as holomorphic maps to the Riemann sphere; proof that holomorphic maps from the Riemann sphere to itself are rational functions (not in the book). BN 10.1: Definition of the residue of a function at a pole in terms of its Laurent expansion and in terms of the integral of the function around a small loop.