摘要：This paper presents a model of a trade of information such that resales of it are freely allowed, yet no agent has the incentive to resell after he acquired it. Agents can communicate with each other in advance of the trade, and make an agreement to prevent resales; but the agreement is not binding. The information can be shared in a set of agents only if the agreement is self-enforcing, and we call such a set of agents a resale-proof set. It is shown that sharing in a resale-proof set of the smallest size is the only outcome that is not dominated by any resale-proof set.
