Mind Switches in Futurama and Stargate
  Let P be a permutation expressed as a product of nontrivial disjoint cycles. When writing P as a product of distinct transpositions none equal to a factor of P, what is the smallest number of transpositions that can be used? We answer this question and give applications to mind-switching problems that have arisen in connection with the popular sci-fi television series Futurama and Stargate SG-1. 
Ron Evans, Lihua Huang
math.GR math.CO