### Abstract

This paper analyzes the worst-case efficiency ratio of false-name-proof combinatorial auction mechanisms. False-name-proofness generalizes strategy-proofness by assuming that a bidder can submit multiple bids under fictitious identifiers. Even the well-known Vickrey-Clarke-Groves mechanism is not false-name-proof. It has previously been shown that there is no false-name-proof mechanism that always achieves a Pareto efficient allocation. Consequently, if false-name bids are possible, we need to sacrifice efficiency to some extent. This leaves the natural question of how much surplus must be sacrificed. To answer this question, this paper focuses on worst-case analysis. Specifically, we consider the fraction of the Pareto efficient surplus that, we obtain and try to maximize this fraction in the worst-case, under the constraint of false-name-proofness. As far as we are aware, this is the first attempt to examine the worst-case efficiency of false-name-proof mechanisms. We show that the worst-case efficiency ratio of any false-name-proof mechanism that satisfies some apparently minor assumptions is at most 2/(m +1) for auctions with m different goods. We also observe that the worst-case efficiency ratio of existing false-name-proof mechanisms is generally 1/m or 0. Finally, we propose a novel mechanism, called the adaptive reserve price mechanism that is falso-nanic-proof when all bidders are single-minded. The worst-case efficiency ratio is 2/(m + 1), i.e., optimal.

Original language | English |
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Title of host publication | 9th International Joint Conference on Autonomous Agents and Multiagent Systems 2010, AAMAS 2010 |

Publisher | International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS) |

Pages | 633-640 |

Number of pages | 8 |

ISBN (Print) | 9781617387715 |

Publication status | Published - Jan 1 2010 |

Event | 9th International Joint Conference on Autonomous Agents and Multiagent Systems 2010, AAMAS 2010 - Toronto, ON, Canada Duration: May 10 2010 → … |

### Publication series

Name | Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS |
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Volume | 1 |

ISSN (Print) | 1548-8403 |

ISSN (Electronic) | 1558-2914 |

### Other

Other | 9th International Joint Conference on Autonomous Agents and Multiagent Systems 2010, AAMAS 2010 |
---|---|

Country | Canada |

City | Toronto, ON |

Period | 5/10/10 → … |

### All Science Journal Classification (ASJC) codes

- Artificial Intelligence

### Cite this

*9th International Joint Conference on Autonomous Agents and Multiagent Systems 2010, AAMAS 2010*(pp. 633-640). (Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS; Vol. 1). International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS).

**Worst-case efficiency ratio in false-name-proof combinatorial auction mechanisms.** / Iwasaki, Atsushi; Conitzer, Vincent; Omori, Yoshifusa; Sakurai, Yuko; Todo, Taiki; Guo, Mingyu; Yokoo, Makoto.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*9th International Joint Conference on Autonomous Agents and Multiagent Systems 2010, AAMAS 2010.*Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS, vol. 1, International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS), pp. 633-640, 9th International Joint Conference on Autonomous Agents and Multiagent Systems 2010, AAMAS 2010, Toronto, ON, Canada, 5/10/10.

}

TY - GEN

T1 - Worst-case efficiency ratio in false-name-proof combinatorial auction mechanisms

AU - Iwasaki, Atsushi

AU - Conitzer, Vincent

AU - Omori, Yoshifusa

AU - Sakurai, Yuko

AU - Todo, Taiki

AU - Guo, Mingyu

AU - Yokoo, Makoto

PY - 2010/1/1

Y1 - 2010/1/1

N2 - This paper analyzes the worst-case efficiency ratio of false-name-proof combinatorial auction mechanisms. False-name-proofness generalizes strategy-proofness by assuming that a bidder can submit multiple bids under fictitious identifiers. Even the well-known Vickrey-Clarke-Groves mechanism is not false-name-proof. It has previously been shown that there is no false-name-proof mechanism that always achieves a Pareto efficient allocation. Consequently, if false-name bids are possible, we need to sacrifice efficiency to some extent. This leaves the natural question of how much surplus must be sacrificed. To answer this question, this paper focuses on worst-case analysis. Specifically, we consider the fraction of the Pareto efficient surplus that, we obtain and try to maximize this fraction in the worst-case, under the constraint of false-name-proofness. As far as we are aware, this is the first attempt to examine the worst-case efficiency of false-name-proof mechanisms. We show that the worst-case efficiency ratio of any false-name-proof mechanism that satisfies some apparently minor assumptions is at most 2/(m +1) for auctions with m different goods. We also observe that the worst-case efficiency ratio of existing false-name-proof mechanisms is generally 1/m or 0. Finally, we propose a novel mechanism, called the adaptive reserve price mechanism that is falso-nanic-proof when all bidders are single-minded. The worst-case efficiency ratio is 2/(m + 1), i.e., optimal.

AB - This paper analyzes the worst-case efficiency ratio of false-name-proof combinatorial auction mechanisms. False-name-proofness generalizes strategy-proofness by assuming that a bidder can submit multiple bids under fictitious identifiers. Even the well-known Vickrey-Clarke-Groves mechanism is not false-name-proof. It has previously been shown that there is no false-name-proof mechanism that always achieves a Pareto efficient allocation. Consequently, if false-name bids are possible, we need to sacrifice efficiency to some extent. This leaves the natural question of how much surplus must be sacrificed. To answer this question, this paper focuses on worst-case analysis. Specifically, we consider the fraction of the Pareto efficient surplus that, we obtain and try to maximize this fraction in the worst-case, under the constraint of false-name-proofness. As far as we are aware, this is the first attempt to examine the worst-case efficiency of false-name-proof mechanisms. We show that the worst-case efficiency ratio of any false-name-proof mechanism that satisfies some apparently minor assumptions is at most 2/(m +1) for auctions with m different goods. We also observe that the worst-case efficiency ratio of existing false-name-proof mechanisms is generally 1/m or 0. Finally, we propose a novel mechanism, called the adaptive reserve price mechanism that is falso-nanic-proof when all bidders are single-minded. The worst-case efficiency ratio is 2/(m + 1), i.e., optimal.

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M3 - Conference contribution

AN - SCOPUS:84899446568

SN - 9781617387715

T3 - Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS

SP - 633

EP - 640

BT - 9th International Joint Conference on Autonomous Agents and Multiagent Systems 2010, AAMAS 2010

PB - International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS)

ER -