雨果·索南夏因对微观经济理论的贡献

Hugo F. Sonnenschein's Contributions to Microeconomics

雨果·索南夏因是美国杰出的经济学家,重点研究一般均衡理论,并因为索南夏因-曼特尔-德布鲁定理而享誉学术界。他的主要贡献包括:(1)率先对超额需求函数结构进行研究,对索南夏因-曼特尔-德布鲁定理的提出有重要贡献,证明了满足特定限制的任意函数都可能是经济体的超额需求函数,此时均衡不唯一且不稳定。这一成果表明了一般均衡理论的不可证伪性,也带来了微观经济学基础和宏观经济学的分离。(2)提出了价格机制的公理化表达方式,塑造了价格的识别机制,为公理化表达社会选择过程做出了突出贡献。(3)通过放松阿罗不可能定理的基本假设、简化吉伯德-萨特思韦特定理的证明和研究防止策略性的机制,推动了投票理论的发展。(4)对鲁宾斯坦讨价还价模型进行了扩展与再检验,将不完全信息情境引入讨价还价模型中,使该模型更具现实解释力。

Hugo F. Sonnenschein, with microeconomics as his main research area, is an outstanding economist in the United States. He focuses on general equilibrium theory and is famous for Sonnenschein-Mantel-Debreu theorem. His main contributions are as follows: Firstly, Sonnenschein takes the lead in analyzing the structure of excess demand function, and proposes the Sonnenschein-Mantel-Debreu theorem, which proves that any function satisfying certain limits may be the excess demand function of the economy. The theorem shows that the equilibrium is non-unique and unstable, which further leads to the unfalsifiablity of general equilibrium theory, and brings also the separation between the micro-foundation and macroeconomics. Secondly, Sonnenschein presents the axiomatic characterization of the price mechanism, distinguishing it from other competitive mechanisms, and promotes the axiomatization of the social selection process. Thirdly, Sonnenschein enriches the voting theory by relaxing the fundamental assumptions of the Arrow's impossibility theorem, simplifies the proof of Gibbard-Satterthwaite theorem, and explores the mechanism of strategy-proofness. Fourthly, Sonnenschein extends and re-examines the Rubinstein bargaining model, by introducing bargaining under incomplete information into the model, which makes the bargaining model more realistic.