When sharing cake between two people, the envy-free recommendation is for one person to cut the cake, making the two pieces as equal as possible, while the other person picks their preferred piece. With this agreement, both people can feel fairly treated.

So how can you share a cake equally with three people so that no one feels any envy about a piece they didn’t get? This recently discovered, multi-step process of cutting and choosing three pieces of cake is demonstrated by mathematician Dr. Hannah Fry for Numberphile.

Related reading: A Discrete and Bounded Envy-Free Cake Cutting Protocol for Any Number of Agents.

Next: The Scientific Way to Cut a Cake.

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