1. The calculation of conformal mapping of an arbitrary simply connected domain to the standard disk.
2. Calculation of 2-Hurwitz numbers of genus 0.
Links:
[1] http://www.mpim-bonn.mpg.de/taxonomy/term/39
[2] http://www.mpim-bonn.mpg.de/node/3444
[3] http://www.mpim-bonn.mpg.de/node/5312