中文摘要：

阐述决策外部性的性质,建立不确定信息群体博弈模型、不完全信息群体博弈模型和群体合作博弈模型,并结合实际的案例分析对模型进行分析。认为,外部效用是群体共同选择接受的激励机制,群体规模是正外部性发挥的保证;信息在群体博弈中具有重要的价值,掌握更对的信息可以避免错误的选择,并使正外部性得到更好的发挥;合作博弈凡是发挥外部应用的最好方式。通过外部性的视对给现实经济生活中的新产品扩散、企业间的默契、企业集群和企业联盟等群体博弈行为予以解释和应用分析。

英文摘要：

This paper has firstly discussed the nature of decision-making externality,then followed by setting up the group gaming model under uncertain information and incomplete information,as well as the cooperative group gaming model.Then this paper also provides some case studies to explain these models in detail.And conclusions drawn are as follows： First,external effectiveness is the group co-opt incentive mechanism,and the group size plays a guarantee role for it.Second,the information in the group game has important values,and gasping more information can avoid the wrong choice,and make positive externalities play better.Furthermore,the cooperative game is the best way to make full use of the externality.In this way,from the view of externality,this paper gives an explanation and applies analysis to the proliferation of new products,tacit agreement among enterprises,enterprise clusters and business alliances in the real economic life by group game theory.