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MTH 325: Complex Analysis


The theory of Complex Analysis came about at the end of the eighteenth century when mathematicians understood the relation between complex numbers and their geometric representation as points in the plane (the complex number z=x+iy can be identified with the point (x,y)). The theory grew very fast: most of the results we see in this class were discovered in a period of about 40 years. It evolved through a beautiful interplay between analysis, geometry and topology. It had immediate repercussions in many fields of mathematics as well as of physics. In mathematics, Complex Analysis has very varied uses in number theory (studying the distribution of prime numbers with the Riemann Zeta function), hyperbolic geometry (isometries of the hyperbolic plane are of the form $ z \mapsto (az+b)/ (cz+d)$, where z is complex), dynamical systems (ever seen a Mandlebrot set?) and many others.


In Complex Analysis, we study complex valued functions f(z) of the complex variable z. The same way we do in Calculus of functions of a real variable, we can define the derivative f' of f as a limit. When this derivative exists, f is called analytic. It turns out that analytic functions have incredibly rich properties. For instance, if a function f is analytic, that is if f' exists, then all its successive derivatives f'', f'''..... exist as well! (you can think of many examples of Calculus where this is not true. Think, for instance, of what happens to the derivative of your displacement when you put on the breaks in a car). A central part of complex analysis is integration, reminiscent of path integration in vector Calculus. Complex variable integration techniques can yield spectacular shortcuts to solutions of complicated Calculus problems.


Complex analytic functions have a fundamental geometric property. If you look at analytic functions as transformations of the plane into itself, they preserve the angles between intersecting curves. Hence eighteenth century mathematicians used complex functions to solve the problem of making geographical maps that preserved angles. This simple property, called conformality, is central to many results in complex analysis, and gives this field of analysis its unique geometric flavor.


This course is a joint offering of the mathematics departments of Smith College and Mount Holyoke College.


next up previous contents
Next: MTH 333: Topics in Up: Some Detailed Course Descriptions Previous: MTH 307: Topics in   Contents
Nicholas Horton 2006-08-27