A Complete Characterization of Group-Strategyproof Mechanisms of Cost-Sharing

Abstract. We study the problem of designing group-strategyproof costsharing mechanisms. The players report their bids for getting serviced and the mechanism decides a set of players that are going to be serviced and how much each one of them is going to pay. We determine three conditions: Fence Monotonicity, Stability of the allocation and Validity of the tie-breaking rule that are necessary and sufficient for group-strategyproofness, regardless of the cost function. Consequently Fence Monotonicity characterizes group-strategyproof cost-sharing schemes closing an inportant open problem. Finally, we use our results to prove that there exist families of cost functions, where any group-strategyproof mechanism has unbounded approximation ratio.

• Type: Conference
• Year: 2010
• Where: ESA
• Authors: Emmanouil Pountourakis, Angelina Vidali
• Keywords: Algorithms, Cost Functions, ESA 2010, Fence Monotonicity, Group-strategyproof Costsharing Mechanisms