# Bernd Kawohl: On Reuleaux and Cohn-Vossen, or buttons and balls that cannot run away

**Time: **
Thu 2022-10-20 15.00 - 16.00

**Location: **
Institut Mittag-Leffler, Seminar Hall Kuskvillan and Zoom

**Video link: **
Meeting ID: 921 756 1880

**Participating: **
Bernd Kawohl (University of Cologne)

**Abstract:**

My lecture centers around convex sets of constant width and the biographies of two scientists from the 19th and 20th century, Franz Reuleaux and Stefan Cohn-Vossen. While some of it is at the level of mathematical entertainment (how to drill a square hole?), it will also contain a deep and only partially answered questions and some aspects on the history of mathematics. To be very specific, geometric aspects of the following nonlinear PDE for the boundary of a convex closed set in Euclidean 3-space will be addressed: \(\min\{ \kappa_1,\kappa_2\}=1\).