Information and Equilibrium

这笔赠款支持对微观经济理论中四个主题的研究。前两个项目的问题调查了“在游戏中学习”的各个方面。这一理论基于这样一种观点，即博弈中的均衡是由于反复观察导致参与者对对手的比赛有共同的预测而产生的；这是广泛使用博弈论均衡概念分析经济问题的主要理由之一。过去关于在游戏中学习的大多数工作都假设，在每一轮比赛结束时，所有玩家都会观察每个人的行为，这意味着例如，在密封投标拍卖中，投标人可以看到所有的投标，而不仅仅是中标者。第一个项目放松了这一假设，研究了当玩家对其他玩家一直在做什么的信息较少时，游戏中学习过程可能产生的长期结果。第二个相关的项目从“在游戏中学习”的角度来研究对不完全信息游戏的解释。该项目的一个特别焦点是质疑“没有共同先验的纳什均衡”解决方案概念的合理性，近年来，该概念已被越来越多的经济分析所使用。第三个项目使用均衡分析来研究两家竞拍相同商品的拍卖行都能生存的条件，就像佳士得和苏富比的情况一样，以及当较大的市场将挤出较小的市场时，就像一些人猜测eBay将对其竞争对手所做的那样。初步的见解是，如果价格的差异也更高，买家可能愿意光顾价格往往更高的市场。第四个项目研究具有私人但几乎公开的信息和通信的无限重复博弈的均衡。更简单的无限重复博弈模型，例如重复版本的“囚徒困境”在经济学和其他社会科学中被广泛使用，该项目将把这种分析扩展到一些情况，在这种情况下，参与者只能得到对方行动的不完美和私人信号--例如，一家公司可能会从意外的订单损失中获得竞争对手秘密降价的证据。

This grant supports research on four topics in microeconomic theory. The first two projects questions investigate aspects of "learning in games." This theory is based on the idea that equilibrium in games arises as the result of repeated observations leading players to have common forecasts of opponents' play; it is one of the primary justifications for the widespread use of game-theoretic equilibrium concepts in analyzing economic problems. Most past work on learning in games has assumed that at the end of each round of play, all players observe everyone's actions, which means for examples that bidders in a sealed-bid auction get to see all of the bids, and not just the winning one. The first project relaxes this assumption, and studies the possible long-run outcomes of learning processes in games when players get less information about what the other players have been doing. A second, and related, project studies the interpretation of games of incomplete information from the "learning in games" viewpoint. A particular focus of the project is to question the plausibility of the solution concept "Nash equilibrium without a common prior," which has been used in an increasing number of economic analyzes in recent years. The third project uses equilibrium analysis to study the conditions under which two competing auction houses for the same goods can both survive, as seems to be the case with Christie's and Sotheby's, and when the larger market will squeeze out the smaller one, as some conjecture that Ebay will do to its rivals. A preliminary insight is that buyers may be willing to patronize a market where prices tend to be higher if the variance of the price is higher as well. The fourth project studies the equilibria of infinitely repeated games with private but almost-public information and communication. Simpler models of infinitely repeated games, such as the repeated version of the "prisoner's dilemma" are widely used in economics and other social sciences, the project will extend this analysis to some cases where players only get imperfect and private signals of one another's actions- for example a firm might get evidence of a rival's secret price cuts from an unexpected loss of orders.