On the Optimality of the Patent Renewal System
研究专利续期制度是否能在研究成本和收益信息不对称的情况下被证明为最优，发现续期机制等价于直接揭示机制，且无法被改进，同时指出在合理情况下专利应具有统一期限而非可变长度。
The patent system is mainly a renewal system: the patent life is chosen by the patentee in return for fees. I ask whether such a system can be justified by asymmetric information on costs and benefits of research. In such a model I show that renewal mechanisms (possibly with subsidies) are equivalent to direct revelation mechanisms and therefore cannot be improved on, regardless of the objective function. Under plausible circumstances, patents should have a uniform life, rather than varying in length, as typically occurs under a renewal system.