Maps, graphs and digraphs, coloring problems, applications.
Graphs, trees, paths and cycles, connectedness, chromatic number, planarity conditions, genus of a graph, the Five Color Theorem. Students should also be aware of Kuratowsky's Theorem, and the Four Color Theorem. If there is time, it is good to study the proof of Kuratowski's Theorem. For more detailed information visit the Math 355 Wiki page.