Competition in two-sided markets
构建了三个双边市场模型：垄断平台、竞争平台（用户只加入一个平台）和竞争瓶颈（一组用户加入所有平台），分析交叉网络外部性、收费方式和用户多归属对均衡价格的影响。
Many markets involve two groups of agents who interact via "platforms," where one group's benefit from joining a platform depends on the size of the other group that joins the platform. I present three models of such markets: a monopoly platform; a model of competing platforms where agents join a single platform; and a model of "competitive bottlenecks" where one group joins all platforms. The determinants of equilibrium prices are (i) the magnitude of the cross-group externalities, (ii) whether fees are levied on a lump-sum or per-transaction basis, and (iii) whether agents join one platform or several platforms.