quasi
Posts:
12,067
Registered:
7/15/05


Re: A New Graph Coloring Conjecture.
Posted:
Jun 26, 2013 4:06 AM


Bill wrote:
>I took a second look at your graph information. When I say >those virtually invisible dots, I had enough to analyze the >graoh for FFS. I found one. It is vetices 1 7 8 9. Not a K4.
Right, the subgraph determined by vertices 1,7,8,9 is not a K4, but it's not what you call a forced 4set, since it's 3colorable.
As I previously noted, if a graph with 4 vertices is not 3colorable, then it must be complete (that is, it must be isomorphic to K4).
quasi

