Time:  12  1:20 p.m. 
Room: 
DH 1209

Speaker: 
James Cummings Associate Professor Department of Mathematical Sciences Carnege Mellon University 
Title: 
Compactness for chromatic numbers of graphs

Abstract:  Let G be a graph with chromatic number kappa. Must it have
a subgraph of size kappa with chromatic number kappa?
This seemingly innoccuous question turns out to be hard. I will try to explain why. 