Mathematics – Combinatorics
Scientific paper
2010-06-18
Electronic J. of Combinatorics, R45 16(1), 2009
Mathematics
Combinatorics
15 pages
Scientific paper
Albertson conjectured that if graph $G$ has chromatic number $r$, then the crossing number of $G$ is at least that of the complete graph $K_r$. This conjecture in the case $r=5$ is equivalent to the four color theorem. It was verified for $r=6$ by Oporowski and Zhao. In this paper, we prove the conjecture for $7 \leq r \leq 12$ using results of Dirac; Gallai; and Kostochka and Stiebitz that give lower bounds on the number of edges in critical graphs, together with lower bounds by Pach et.al. on the crossing number of graphs in terms of the number of edges and vertices.
Albertson Michael O.
Cranston Daniel W.
Fox Jacob
No associations
LandOfFree
Crossings, colorings, and cliques does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Crossings, colorings, and cliques, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Crossings, colorings, and cliques will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-261353