Mathematics and Statistics Colloquium

Calvin University

Kelsey Brouwer
Aquinas College

November 20, 2025
3:05pm   •   North Hall 276

External Rays and Paper Fortune Tellers:
An exploration of baby Julia sets and their Alterations

Julia sets describe which complex numbers have stable behavior when iterated through a map an infinite number of times. In this talk, we introduce external rays as a way of analyzing quadratic Julia sets, then adapt the technique to analyze Julia sets of the Generalized McMullen map \(z^n + a/z^n + b\), which contain homeomorphic “baby” copies of quadratic Julia sets and their altered preimages. Through this adaptation we are able to describe the dynamics of these altered preimages for the first time.