When: 
Tuesday, March 7, 2017 - 12:15pm - 1:15pm
Where: 
Pardee 217
Presenter: 
Bruce E. Sagan, Michigan State University
Price: 
All are welcome and pizza will be served in Pardee 218 before the talk.

Let t be a positive integer and let G be a combinatorial graph with vertices

V and edges E. A proper coloring of G from a set with t colors is a function c :

V  {1, 2, …, t} such that if uv ϵ E then c(u) c(v), that is, the endpoints

of an edge must be colored differently. These are the colorings considered in

the famous Four Color Theorem. The chromatic polynomial of G, P(G; t), is

the number of proper colorings of G from a set with t colors. It turns out that

this is a polynomial in t with many amazing properties. One can characterize

the degree and coefficients of P(G; t). There are also connections with acyclic

orientations of G, hyperplane arrangements, symmetric functions, and Chern

classes in algebraic geometry. This talk will survey some of these results.

Sponsored by: 
Department of Mathematics

Contact information

Name: 
c. jayne trent
Phone: 
610-330-5267
Email: 
trentj@lafayette.edu