On Rothschild–Stiglitz as Competitive Pooling

Dubey and Geanakoplos (Q J Econ 117:1529–1570, 2002) have developed a theory of competitive pooling, which incorporates adverse selection and signaling into general equilibrium. By recasting the Rothschild–Stiglitz model of insurance in this framework, they find that a separating equilibrium always exists and is unique. We prove that their uniqueness result is not a consequence of the framework, but rather of their definition of refined equilibria. When other types of perturbations are used, the model allows for many pooling allocations to be supported as such: in particular, this is the case for pooling allocations that Pareto dominate the separating equilibrium.     

On the dynamics of inequality

The dynamics of inequality are studied in a model of human capital accumulation with credit constraints. This model admits a multiplicity of steady state skill ratios that exhibit varying degrees of inequality across households. The main result studies equilibrium paths. It is shown that an equilibrium sequence of skill ratios must converge monotonically to the smallest steady state that exceeds the initial ratio for that sequence. Convergence is “gradual" in that the steady state is not achieved in finite time. On the other hand, if the initial skill ratio exceeds the largest steady state, convergence to a steady state is immediate.This paper is based on unpublished notes from 1990; see http://www.econ.nyu.edu/user/debraj/DevEcon/Notes/incdist.pdf. Two considerations suggest that these results may be worth reporting in print. First, the existence of a sizeable recent literature indicates that these relatively early notes may have value outside a filing cabinet or a private webpage. Second, Mukul Majumdar’s own research on economic growth with a nonconvex technology is an even earlier precursor to some of this literature, so the current outlet – a special issue in his honor – seems appropriate. Conversations with Glenn Loury simplified the proof of the main result. I thank Dilip Mookherjee for many useful discussions, and two anonymous referees for helpful comments on an earlier draft. Funding from the National Science Foundation under grant number 0241070 is acknowledged. This paper is dedicated with much affection and warm admiration to Mukul Majumdar – or to Mukulda, as I always think of him – on the occasion of his 60th birthday.     

Monopoly Power and Stagflation

Post Keynesian economists have followed Joan Robinson's criticism of general equilibrium theory as abolishing history by allowing all contracts to be executed today for all future contingencies. This was the justification for the support of financial innovation to provide for the completeness of futures markets. The recent crisis has shown that force of history. Instead, many evolutionary and Keynesian economists have suggested the approach of cumulative causation as an approach that includes history and eschews equilibrium. This approach may provide a way to take history seriously in economic analysis.     

跨国汽车公司环境责任研究——基于动态面板数据的回归分析

本文基于动态面板数据,对13家著名跨国汽车公司进行了实证研究。研究表明,履行环境责任对跨国汽车公司在利润率水平和公司排名等方面产生影响。影响方向可能是正向,也可能是逆向;影响时间可能是即期,也可能是滞后一期、或滞后两期。影响程度因公司而异,但总体来说,没有表现出明显的地区差异。     

博弈论视角下的产品质量安全问题研究

近年来,我国频繁爆发产品质量安全事件,从"瘦肉精"、"染色馒头"到"一滴香"、"三聚氰胺"等,产品质量安全问题日益成为影响社会和谐与稳定的重要因素之一,阻碍和制约了我国经济的又好又快发展。本文首先梳理了产品质量安全相关的研究成果,随后从博弈论的角度出发,建立企业和消费者之间的完全信息动态博弈模型,分析企业和消费者为实现各自利益最大化而采取的策略,得出企业和消费者的纳什均衡结果.进而达到探寻产品质量安全产生根源,提出相应对策建议的目的。