Intermediation, Information, and Diversity in Networks

网络中的中介、信息和多样性

• 批准号: 1260744
• 负责人: Mihai Manea
• 金额: $ 27.61万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-15 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1260744&HistoricalAwards=false
• 关键词: Intermediation; Information; Diversity; Networks

Networks are ubiquitous in economic and social contexts. Individual decisions and welfare are affected by local connections, as well as by global network architecture. The research funded by this award investigates how the networks in which agents interact influence outcomes in a variety of market and group activities. There are three distinct projects. The first two investigate the impact of network structure on trade intermediation and information diffusion. The third project examines what network features are essential for the persistence of diversity in socially influenced choices.The first project studies intermediation in networks. The theory suggests that the seller's profit depends not only on the number of middlemen along the path of trade, but also on the complete collection of competing paths of access to buyers offered by each middleman. The seller prefers to trade along paths that entail local competition among intermediaries with similar resale values. Trading paths do not necessarily minimize intermediation or maximize welfare. A decomposition of the network into layers of intermediation power characterizes equilibrium resale profits. Local competition is exploited within layers and hold-up problems arise in transactions across layers. This research has implications for combating organized crime and illegal trade, preventing corruption in hierarchical structures, and efficient production in supply chains. The second project investigates how information (technological innovations, research ideas, news and gossip) is priced and diffused across the links of a network. In contrast to the research on intermediation, the information good is non-rival; any player who gets possession of the good may subsequently replicate and resell it to an arbitrary number of uninformed neighbors. The positions of the initial sources of information in the network affect the profits that actors accrue from acquiring and reselling the information and shape the diffusion process. Sellers compete for customers and establish individual spheres of influence in the network. The main objective is to prove that profits are confined within the blocks of a certain network partition. Links with endpoints within the same block constitute bottlenecks and play an important role in extracting profits. Links bridging across blocks are not critical in connecting the network and impose negative externalities on sellers. The third project considers a setting where players situated in a network need to take actions or form opinions that conform with a majority of their neighbors. Unanimous coordination on any particular action constitutes an equilibrium. Many networks also feature equilibria with diverse action choices. The aim of this research is to characterize the networks for which diversity is robust to the introduction of stochastic mutations in the best response dynamic. The tools and methods developed in this research will provide broader impact by allowing firms and policymakers to better understand how network relationships affect market outcomes.

网络在经济和社会环境中无处不在。个体的决策和福利既受到本地联系的影响，也受到全球网络架构的影响。由该奖项资助的研究调查了代理人在各种市场和群体活动中相互作用的网络如何影响结果。有三个不同的项目。前两篇研究网络结构对贸易中介和信息扩散的影响。第三个项目考察了哪些网络特征对社会影响选择的多样性持久性至关重要。第一个项目研究网络中的中介。该理论认为，卖方的利润不仅取决于交易路径上中间商的数量，还取决于每个中间商提供的与买方接触的竞争路径的完整集合。卖方倾向于在具有相似转售价值的中介之间进行本地竞争的路径上进行交易。交易路径不一定会减少中介或最大化福利。将网络分解为中介权力层是均衡转售利润的特征。在层内利用本地竞争，并在跨层交易中出现拖延问题。这项研究对打击有组织犯罪和非法贸易、防止等级结构中的腐败以及供应链中的高效生产具有启示意义。第二个项目调查信息（技术创新、研究想法、新闻和八卦）是如何定价并在网络的各个环节中传播的。与中介研究相反，信息商品是非竞争性的；任何获得该物品的玩家随后都可能复制并转售给任意数量的不知情邻居。初始信息源在网络中的位置影响行动者从获取和转售信息中获得的利润，并影响传播过程。卖家争夺客户，在网络中建立各自的势力范围。主要目标是证明利润被限制在某一网络分区的区块内。与同一区块内端点的链接构成瓶颈，并在获取利润方面发挥重要作用。跨区块的链接在连接网络方面并不重要，并对卖家施加负外部性。第三个项目考虑了这样一个场景，即处于网络中的玩家需要采取行动或形成与大多数邻居一致的意见。对任何具体行动的一致协调构成均衡。许多网络还具有具有不同行动选择的均衡。本研究的目的是表征在最佳响应动态中引入随机突变时多样性具有鲁棒性的网络。本研究中开发的工具和方法将提供更广泛的影响，使企业和政策制定者能够更好地理解网络关系如何影响市场结果。