# Applications of Four Color Theorem [duplicate]

I tried finding real life applications for the Four Color Theorem (except for coloring maps) but couldn't find anything useful and well illustrated. For example I found this:

Graph coloring problems are widely applicable to the problem of scheduling.

Consider a university, where you are trying to schedule times for all of the final exams. Some students are taking more than one class, so you want to make sure they don't have two exams scheduled at the same time. However, you want your exam writing period to be as short as possible, to run as many exams concurrently as you can.

You can represent this as a graph coloring problem: construct a graph in which each class is a vertex, and there is an edge between vertices any time a two classes contain the same student. Your colors will represent different exam timeslots. The minimum number with which you can color that graph is the smallest number of timeslots you need to write all your exams.

source: jmite on cs.se.

However, I don't really get how it works! Also if you could give more examples related with graph theory and four color theorem

• Frankly, I'm not sure that the four color theorem has any real life applications. Commented Dec 13, 2016 at 10:14
• The quoted text comes from this answer. If you're going to quote text, you must attribute the source. Commented Dec 13, 2016 at 12:22