Speaker
Maya Sankar (Stanford)
Date
Mon, Nov 4 2024, 1:00pm
Location
384H

A Cayley graph G is a highly symmetric graph whose vertex set is a finite group Gamma. A rather surprising theorem, due to Payan, shows that, if Gamma is (Z/2Z)^n, then G cannot have chromatic number exactly 3. (In other words, if G is 3-colorable then G is also 2-colorable.) I'll show you a new elementary proof of Payan's theorem, and tell you about the oldest result in topological combinatorics along the way. Come find out how I got away with putting a commutative diagram in a combinatorics paper!