User joe zeng - MathOverflow most recent 30 from http://mathoverflow.net 2013-06-19T00:55:19Z http://mathoverflow.net/feeds/user/27459 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/110337/are-there-any-non-planar-graphs-containing-only-k3-3-as-a-subgraph-that-are-not Are there any non-planar graphs containing only K(3,3) as a subgraph that are not 4-colourable? Joe Zeng 2012-10-22T14:58:14Z 2012-11-23T04:59:32Z <p>It's obvious why any graph containing K(5) wouldn't be 4-colourable, but what about graphs containing only instances of K(3,3) to assert their non-planarity?</p> <p>(Edit: By a graph "containing" another graph, I mean having it as a subgraph. Sorry for being unclear. Although now that I think about it, perhaps the word "minor" is better.)</p> http://mathoverflow.net/questions/110337/are-there-any-non-planar-graphs-containing-only-k3-3-as-a-subgraph-that-are-not/110774#110774 Comment by Joe Zeng Joe Zeng 2012-11-23T05:00:43Z 2012-11-23T05:00:43Z This answer helped me clear up my own misconceptions about the problem. Thanks for the detailed explanation. http://mathoverflow.net/questions/110337/are-there-any-non-planar-graphs-containing-only-k3-3-as-a-subgraph-that-are-not/110340#110340 Comment by Joe Zeng Joe Zeng 2012-10-26T15:03:08Z 2012-10-26T15:03:08Z I did in fact mean subgraph initially, but the problem of minors is probably more meaningful. http://mathoverflow.net/questions/110337/are-there-any-non-planar-graphs-containing-only-k3-3-as-a-subgraph-that-are-not Comment by Joe Zeng Joe Zeng 2012-10-26T14:45:55Z 2012-10-26T14:45:55Z Gerry Myerson's interpretation is correct. Sorry for being unclear.