Theoretical and Observable Implications of Market Equilibria

克里斯蒂娜·香农理解市场的运作是经济学的基本挑战之一。这种理解既需要详细描述各种不同市场结构或制度下均衡性质的理论工作，也需要一个可以驳斥这些理论和检验假设的经验框架，这些工作包括详细说明各种不同市场结构或制度下均衡的性质，并建议何时可能或希望有特定的市场结构。这个项目试图通过研究几种不同市场结构的理论和可观察到的影响来进一步理解竞争和非竞争市场。这个项目由四个不同的部分组成。前两部分侧重于竞争性市场的理论和可观察的影响。经典的Arrow-Debreu模型为研究竞争行为的许多方面提供了丰富的理论框架，是现代宏观、金融、公共财政等众多领域工作的基础。然而，一般均衡理论经常因为缺乏经验内容而受到批评。这种批评通常基于Sonnenschein-Debreu-Mantel定理，该定理表明，除了连续性和同质性之外，个人需求的任何属性都不会通过市场过剩需求的聚集来保持。在她之前的NSF拨款中，这位研究人员表明，与这一观点相反，一般均衡模型确实对价格、个人收入和总消费的有限观察集施加了可检验的限制，并且它们给出了这样一个有限数据集在瓦拉斯环境下可合理化的充要条件。这个项目的第一部分研究了竞争均衡的定性性质，如局部和全局唯一性、比较静力学和价格调整过程的稳定性，在多大程度上是有限数据集可驳斥的。第二部分考虑了包含金融市场的动态一般均衡经济中的类似问题。最后几节集中于一些代理人采取战略行动的市场的可观察到的影响。特别是，项目的第三部分考虑了有限的观察集合是否可以发现一般均衡集合中的不完全竞争行为，最后一部分考虑这样的数据是否可以提供选择问题和市场中互补性的证据。

Christina ShannonSBR-9818759Understanding the functioning of markets is one of the fundamental challenges in economics. Such understanding requires both theoretical work that details the properties of equilibria under a va-riety of different market structures or institutions and suggests when particular market structures are likely or desirable, and an empirical framework in which these theories can be refuted and hypotheses can be tested. This project seeks to further understanding of competitive and non-competitive markets by studying both theoretical and observable implications of several different market structures. This project has four distinct parts. The first two parts focus on theoretical and observable implications of competitive markets. The classical Arrow-Debreu model provides a rich theoretical framework in which to study many aspects of competitive behavior, and is the foundation for much work in modern macro, finance, public finance, and numerous other fields. General equilibrium theory is often criticized, however, for lacking empirical content. This criticism is typically based on the Sonnenschein-Debreu-Mantel theorem, which shows that no properties of individual demand beyond continuity and homogeneity are preserved by aggregation in market excess demand. Under her previous NSF grant, the investigator showed that, contrary to this view, the general equilibrium model does impose testable restrictions on a finite set of observations of prices, individ-ual incomes, and aggregate consumption, and they give necessary and sufficient conditions for such a finite data set to be rationalizable in a Walrasian setting. The first part of this project studies the extent to which qualitative properties of competitive equilibria, such as local and global uniqueness, comparative statics, and stability of price adjustment processes, are refutable with finite data sets. The second part considers similar questions in a dynamic general equilibrium economy incorporat-ing financial markets. The final sections focus on the observable implications of markets in which some agents act strategically. In particular, the third part of the project considers whether a finite set of observations can detect imperfectly competitive behavior in a general equilibrium set-ting, and the final part considers whether such data can provide evidence of complementarities in choice problems and in markets.