Graph Theory Seminar - Thomas Perrett

Title: Chromatic roots and minor closed classes of graphs

Abstract: The real and complex roots of chromatic polynomials, which we call chromatic roots, have been studied since the 1940s yet there are simply stated problems which remain open. In particular it is not well understood how structural properties of graphs affect their chromatic roots. In this talk we present recent work on the following question: For a minor-closed class of graphs, what is the infimum of the non-trivial real chromatic roots of the graphs in that class?