Inefficiency in a frictionless market
指出Gale和Sabourian（2006）关于动态匹配与议价博弈中马尔可夫策略导致低效率的结论存在错误，证明在四人市场中所有马尔可夫完美均衡都是有效的，但构造了六人市场中的连续低效率均衡，说明低效率源于异质性估值与参与者数量带来的策略不确定性。
Gale and Sabourian (2006) argue that Markov strategies in dynamic matching and bargaining games accommodate non-competitive behavior: with heterogeneous players, outcomes may be inefficient. In this paper, I show that their corroborating example with four players does not comprise a Markov perfect equilibrium (MPE). In fact, I show that all MPEs must be efficient in their setting with only four players. Nevertheless, I construct a continuum of inefficient equilibria in a balanced market with six players. Key to the construction is the dispersion of reservation prices to render inefficient trades individually rational, yet sufficient dynamics of continuation payoffs can be supported only with at least six players. Consequently, inefficiencies are driven by the interplay of heterogeneous valuations and strategic uncertainty from the number of players in the market.