Price-oriented, Rationing-free Protocol: Guideline for Designing Strategy/False-name Proof Auction Protocols

We identify a distinctive class of combinatorial auction protocols called a Price-oriented, Rationing-free (PORF) protocol, 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 strategy regardless of the declarations of other agents. Furthermore, 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 falsename-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 values of other agents, while it is independent of its own declaration. 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. Furthermore, we develop a new false-name-proof PORF protocol.