一个具有购买势力的连锁企业在多个地方市场上分别与一个没有购买势力的地方企业进行Stackelberg竞争，其中连锁企业是纯粹追求利润的私营企业，而地方企业是部分追求利润、部分追求社会福利的国有企业。我们分析了连锁企业的购买势力对企业利润、消费者剩余以及社会福利等的影响。研究表明：连锁企业的利润随着其购买势力的增大而增加，但是，地方企业的利润与上游厂商的利润取决于地方企业国有股的比重和连锁企业购买势力的大小；购买势力的存在降低了消费者剩余、产业利润和整个社会的福利水平。

We study the dependence of incentives for product innovation on the presence, or absence, of parallel trade. The common assertion is that the presence of parallel trade lowers the incentive for product innovation. Our results support this assertion for some parameter values. However, there are cases in which the presence of parallel trade increases research intensity. For this to occur the innovating firm must already produce and export another good. Further, the new good and the old must be close substitutes and have different transportation costs.

This paper incorporates a durable-good monopoly model and re-examines the argument on licensing contracts. It shows that, from the perspective of the non-producing patent holder, the optimal licensing contract depends on the nature and the degree of the innovations. Specifically, for small cost-reducing or quality-improving innovations, charging a royalty is optimal. For large costreducing or quality-improving innovations, licensing by means of a fee and a royalty is superior to using either alone. However, for the case of horizontal product innovations, using a fee contract is optimal.

本文建立了一个平行进口模型，其中一个生产厂商已经拥有一种产品，并考虑开发另一种新产品，通过比较新旧产品的平行进口对厂商产品开发的不同影响，我们发现，对创新产品的平行进口预期或者为遏制创新产品的平行进口所作的可能的努力，更加打击生产厂商从事产品开发的积极性。

We develop a two-country model of endogenous investment in process innovation by a manufacturer facing competition from parallel imports (PI). We find that the distortions associated with PI inhibit innovation. However, the difference between the manufacturer's expected profits under successful and failed innovation is U-shaped in the cost of engaging in PI. Thus, the reduction in R&D investment depends on both legality of PI and transport costs. The reduction in innovation could harm global welfare, depending on whether the manufacturer was deterring PI with a high wholesale price. If so, banning such trade would raise expected welfare.