通过界定垄断阶段和双寡头竞争阶段,在市场未完全覆盖条件下,构建纵向差异化下产品创新企业序贯进入的博弈模型,分析产品的差异化对企业利润、博弈均衡和社会福利的影响。研究表明：产品差异化的不同区间分别对应四种不同的均衡；企业可预判与对手的产品差异化水平从而选择均衡利润；社会福利在可行区间上呈现不同的变化趋势,政府可根据最优的差异化水平制定相应的专利制度,实现社会福利最大化。

By defining the monopoly and duopoly, under not covered market,this paper built a game model of sequential innovation with vertical product differentiation and investigated the effects of the product differentiation on the firms’ profits, game equilibrium and social welfare. The results show that (i) four equilibrium exists in the different intervals of product differentiation respectively; (ii) firms can predict product difference so as to choose the equilibrium profit; (iii) since the social welfare varies in the feasible interval, the government can make patent system to maximize the social welfare according to the optimal level of difference.

F273.2

国家自然科学基金项目（面上项目，重点项目，重大项目）