Futurama theorem

Etymology
From "" (2010), season 6, episode 10 of . The episode and the theorem were written by the mathematician.

Proper noun

 * 1)  A theorem which proves that, given a mind swap machine that can't be used on the same pair of people more than once, it is possible to reverse any number of mind swaps by introducing two more people that did not have their minds swapped with anyone before.