Learn About Fair Division
Fair division means dividing resources in a way that's provably fair for everyone involved. Since Hugo Steinhaus first described the “cake cutting” problem in 1944, researchers in Economics, Mathematics, and Computer Science have developed hundreds of methods for mathematically fair sharing.
Most of these methods are math theories but a few are quite useful for everyday things as well. For example, settling inheritance disputes, deciding fair rent between roommates, or splitting up chores. Some methods are even used to settle resource disputes between countries!
Should I be using these methods?
Maybe! Here are a few tools that use fair division methods:
- New York Times's Divide Your Rent Fairly
- This website's Resource Splitting Tool for divisible resources like cakes, time spans, physical space.
In everyday activities, it's probably best to talk things through and reach a mutual agreement with others. Fair division methods are most suited for situations where people can't agree but we still want everyone gets a fair share.
If you are curious to learn the logic behind provably fair solutions, I've developed a fun, interactive course. You'll get to explore the famous cake cutting problem, which is the heart of the fair division field. Please check it out!
Division with the Selfridge-Conway Method
Let's see how to create an envy-free outcome.
Here is the problem again:
The cake is split using the Selfridge-Conway Method.
Due to the trimming step, the cake has been cut into more pieces than before.
Although a bit more involved than before, this solution is both proportional and envy-free!
For an explanation as to why this is guaranteed to be envy-free, see the wikipedia page for the Selfridge-Conway Method.