a Theoretical and Positive Study on Pro-Patent Policy and Competition Policy of Economic Performance in Information Technologies

本文研究了两家双寡头企业在技术弱互补经济和技术完全互补经济下的研发投资竞争。在前一种经济中，我们假设每个企业都可以在没有这两种技术的情况下生产产品，但它产生的冗余成本比在每种或两种技术都可用的情况下产生的冗余成本要高。在后一种经济中，我们假设没有企业能够在没有这两种技术的情况下生产商品。针对这两种情况，我们分别推导了两种技术在有（交叉）许可制度和没有（交叉）许可制度下的研发投资竞争均衡。通过比较两种均衡下的研发投资水平，我们发现当双寡头企业可以利用两种弱（完全）互补的技术生产产品时，（交叉）许可制度阻碍了研发投资。进一步，我们考虑了两家双寡头企业独立投资于两种现有互补技术的新集成技术以生产产品的研发投资竞争博弈。每家公司都拥有两种老技术中的一种的专利。如果一个企业在生产和供应该产品时没有与另一个企业签订许可合同，则该企业要么使用自己开发的新的集成技术，要么使用竞争对手的现有专利技术来承担损害赔偿。我们证明了该博弈中存在对称纳什均衡。给出了对称平衡点局部稳定的一个充分必要条件。

In this study, we consider the R&D investment competition of the two duopolistic firms in both weakly complementary technologies economy and completely complementary technologies. In the former economy, we assume that each firm can produce goods without both of the two technologies but it incurs more redundant costs than that in the case each or both of the technologies may be available for it. By the latter economy, we assume that no firm can produce the goods without both of the technologies. For these two cases, we derive the investments competition equilibria in R&D of the two technologies with and without the (cross-) licensing system. By comparing of the R&D investment levels in the two equilibria, we show that the (cross-) licensing system discourages the R&D investments when the duopolistic firms can produce goods by using of the two weakly (completely) complementary technologies. Furthermore, we consider the R&D investments competition game of the two duopolistic firms which independently invest in the new integrated technology of the two existing complementary technologies to produce the good. Each firm has the patent of one of the two old technologies. If each firm produces the product and supplies it without license contract held by another firm, it incurs the compensation for damages in either by use of the new integrated technology developed by it or the existing technology patented by its rival. We show the existence of symmetric Nash equilibria in the game. We also present a necessary and sufficient condition for local stability of the symmetric equilibria.