**Prof. Ted Suffridge**

University of Kentucky

**"Hadamard Products and Space Capsules"**

**Abstract:**

The Hadamard product of two analytic functions, and given by power series

and

is

There is no clear geometric connection among the properties of and . The interesting paper of G.
Pólya and I.J. Schoenberg that appeared in the Pacific Journal of Mathematics in 1958 suggested that there are some
interesting connections. For example, they conjectured that the family of analytic functions that map the unit disk
onto convex domains is preserved under Hadamard products. This conjecture was proved by Ruscheweyh and
Sheil-Small in 1973. In this talk, we will survey the known geometric properties of Hadamard products. The talk
will include the definition and a discussion of "primes" under this product as well as some recent results of
Ruscheweyh and Suffridge. What does this have to do with space capsules? We will show that the if maps the
unit disk onto an infinite strip and maps the unit disk onto an infinite wedge, then maps maps the disk
onto a region that resembles a space capsule.

#### Friday, October 26, 2001

3:00 PM in 335 Jabara Hall

Please join us for refreshments before the lecture at 2:30p.m. in room 353 Jabara Hall.

[ Fall 2001]