Makoto Yokoo, Yuko Sakurai, and Kenji Terada
We identify a distinctive class of combinatorial auction pro-tocols called a Price-oriented, Rationing-free (PORF) pro-tocol, which can be used as a guideline for developing strategy/false-name proof protocols. A PORF protocol is automatically guaranteed to be strategy-proof, i.e., for each agent, declaring its true evaluation values is an optimal strat-egy regardless of the declarations of other agents. Further-more, if a PORF protocol satisfies additional conditions, the protocol is also guaranteed to be false-name-proof, that is, it eliminates the benefits from using false-name bids, i.e., bids submitted under multiple fictitious names such as multiple e-mail addresses. For Intemet auction protocols, being false-name- proof is important since identifying each participant on the Intemet is virtually impossible. The characteristics of a PORF protocol are as follows. For each agent, the price of each bundle of goods is presented. This price is determined based on the declared evaluation val-ues of other agents, while it is independent of its own declara-tion. Then, each agent can choose the bundle that maximizes its utility independently of the allocations of other agents (i.e., mOoning-free). We show that an existing false-name-proof protocol can be represented as a PORF protocol. Further-more, we develop a new false-name-proof PORF protocol.