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

在本研究中，我们考虑了两个双寡头企业在弱互补技术经济和完全互补技术经济下的R&D投资竞争。在前一种经济中，我们假设每个企业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两种技术都可用的情况下要多;在后一种经济中，我们假设没有两种技术的情况下没有企业可以生产产品。对于这两种情况，我们推导出了在有和没有（交叉）许可制度的情况下，这两种技术的R&D投资竞争均衡。通过比较两种均衡下的R&D投资水平，我们发现当双寡头企业可以利用两种弱（完全）互补技术生产产品时，（交叉）许可制度会抑制R&D投资。此外，我们考虑的R&D投资竞争博弈的两个双寡头企业独立投资于新的集成技术的两个现有的互补技术，以生产好。两家公司都拥有两项老技术中的一项的专利。如果每个公司生产和供应产品，而没有另一家公司持有的许可证合同，它就会因使用自己开发的新的综合技术或竞争对手的现有专利技术而受到损害赔偿。我们证明了对称纳什均衡的存在性。我们也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.