A lower bound for scheduling mechanisms. Elias Koutsoupias and Angelina Vidali, 18th ACM-SIAM Symposium on Discrete Algorithms (SODA'07)

We study the mechanism design problem of scheduling tasks on n unrelated machines in which the machines are the players of the mechanism. The problem was proposed and studied in the seminal paper of Nisan and Ronen, where it was shown that the approximation ratio of mechanisms is between 2 and $n$. We improve the lower bound to $1 + \sqrt{2}$ for 3 or more machines.