ABSTRACT
Figure TIII.8. Nonplanar-ness personified.
24. Let G be an n-vertex rooted tree, where each vertex has either 0 or k descendants. Given a fixed k, for which values of n is this possible?
25. Give an example of a graph with largest degree equal to twice the chromatic number. Does there exist a graph with chromatic number equal to twice the largest degree? If so, give an example, and if not, explain why not.
