Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Note to Quasi from Bill
Posted:
Jun 20, 2013 7:38 PM


I don't seem to be able to post a reply or contact google for help. So I am answering your comments in a separate post. My comments are indented.
What are MA vertices?
mutually adjacent vertices. Then connect vertex 5 to each of the first four. No. Any noncomplete graph with 5 vertices is 4colorable. Not if the graph is nonplanar.
If there are no forceable sets of four vertices the graph must be 4 colorable. Except that I've already shown you a counterexample.
Is your example planar? bill



