“…Remarkably, most known group-strategyproof mechanisms for non-submodular cost functions nevertheless rely on cross-monotonic cost-sharing methods and use a simple mechanism given by Moulin [27] that guarantees groupstrategyproofness. Cross-monotonic cost-sharing methods have been suggested for TSP, Minimal Spanning Tree, and Steiner Tree [22,23], Steiner Forest [24,25], Facility Location [9,26,29], Multi-Commodity-Rent-or-Buy [6], Single-Source-Rent-or-Buy [18,29], Set Cover [9], and Multicast [2,10,11]. Only the methods for Minimal Spanning Trees achieve budget-balance.…”