Limitations of VCG-based mechanisms

GROWRANGE: Anytime VCG-Based Mechanisms

We introduce anytime mechanisms for distributed optimization with self-interested agents. Anytime mechanisms retain good incentive properties even when interrupted before the optimal solution is computed, and provide better quality solutions when given additional time. Anytime mechanisms can solve easy instances of a hard problem quickly and optimally, while providing approximate solutions on v...

Approximations by Computationally-Efficient VCG-Based Mechanisms

We consider computationally-efficient incentive-compatible mechanisms that use the VCG payment scheme, and study how well they can approximate the social welfare in auction settings. We obtain a 2-approximation for multi-unit auctions, and show that this is best possible, even though from a purely computational perspective an FPTAS exists. For combinatorial auctions among submodular (or subaddi...

Undominated VCG redistribution mechanisms

Many important problems in multiagent systems can be seen as resource allocation problems. For such problems, the well-known Vickrey-Clarke-Groves (VCG) mechanism is efficient, incentive compatible, individually rational, and does not incur a deficit. However, the VCG mechanism is not (strongly) budget balanced: generally, the agents’ payments will sum to more than 0. Very recently, several mec...

EPIC Mechanisms and VCG

Amplified Hardness of Approximation for VCG-Based Mechanisms

If a two-player social welfare maximization problem does not admit a PTAS, we prove that any maximal-in-range truthful mechanism that runs in polynomial time cannot achieve an approximation factor better than 1/2. Moreover, for the k-player version of the same problem, the hardness of approximation improves to 1/k under the same two-player hardness assumption. (We note that 1/k is achievable by...