ABSTRACT
First, however, we will set the mathematical stage by exploring planar graphs a bit.
11.2 Try This! Planarity Explorations If we can draw a graph in the plane (on a piece of paper, on the blackboard, etc.) without edges crossing, then the graph is planar. A graph can be planar but be drawn in a nonplanar way-just make one of the edges curly and wild and long so that it crosses every other edge of the graph. Recall that Kn is the complete graph on n vertices, so that all possible edges are present, and that Kn,m is the complete bipartite graph with n vertices in one part and m vertices in the other part.
