De Grey pitched the problem of finding the minimal five-color graph to Terence Tao, a mathematician at the University of California, Los Angeles, as a potential Polymath problem. Polymath began about ...

The graph below shows the total number of publications each year in Graph Coloring and Chromatic Number. References [1] On the Chromatic Number of (P5, C5, Cricket)-Free Graphs .

After more than 70 years of intransigence, one of the most stubborn numbers in math has finally budged. In a four-page proof posted in late September, David Conlon and Asaf Ferber provided the most ...

This graph cannot be colored with just three colors, but four will do the trick. Black dots denote that the pattern can be repeated on an infinite plane. (Image credit: Aubrey de Gray/arXiv/CC by 4.0) ...