Existence of a competitive equilibrium in a one sector growth model with heterogeneous agents and irreversible investment

Summary. We prove existence of a competitive equilibrium in a version of a Ramsey (one sector) model in which agents are heterogeneous and gross investment is constrained to be non negative. We do so by converting the infinite-dimensional fixed point problem stated in terms of prices and commodities into a finite-dimensional Negishi problem involving individual weights in a social value function. This method allows us to obtain detailed results concerning the properties of competitive equilibria. Because of the simplicity of the techniques utilized our approach is amenable to be adapted by practitioners in analogous problems often studied in macroeconomics. Received: September 13, 2001; revised version: December 9, 2002 RID="*" ID="*" We are grateful to Tapan Mitra for pointing out errors as well as making very valuable suggestions. Thanks are due to Raouf Boucekkine and Jorge Duran for additional helpful discussions. We also thank an anonymous referee for his/her helpful comments. The second author acknowledges the financial support of the Belgian Ministry of Scientific Research (Grant ARC 99/04-235 “Growth and incentive design”) and of the Belgian Federal Goverment (Grant PAI P5/10, “Equilibrium theory and optimization for public policy and industry regulation”). Correspondence to: C. Le Van     

简化一般均衡模型中一般均衡点的确定

经济学教材在讨论一般均衡的时候,往往以两个人、两种生产要素、两种产品这种最简单的社会作为研究对象,它们通常只阐述了一般均衡的存在,但都没有说明这种最简单的社会一般均衡点的确定即以此作为研究对象。     

人类能最终战胜“人口魔鬼”吗？

界定了两种"人口魔鬼"的概念,并简单回顾了人类与"人口魔鬼"斗争的历程.在今后几十年或者稍长的时间里,世界人口总数不会无限增殖下去,人类有望战胜"过剩人口魔鬼".但在达到人口顶峰后,由于人口持续缩减,人类的未来不太乐观.     

Self-enforcing international environmental agreements with a stock pollutant

In this paper the stability of an International Environmental Agreement (IEA) among N identical countries that emit a pollutant are studied using a two-stage game. In the first stage each country decides noncooperatively whether or not to join an IEA, and in the second stage signatories jointly against nonsignatories determine their emissions in a dynamic setting defined in continuous time. A numerical simulation shows that a bilateral coalition is the unique self-enforcing IEA independently of the gains coming from cooperation and the kind of strategies played by the agents (open-loop or feedback strategies). We have also studied the effects of a minimum participation clause finding that for this case a self-enforcing IEA just consists of the number of countries established in the clause.JEL Classification: C73, D62, Q28 Corresponding author : Santiago J. RubioThis paper is based on chapter four of Begoña Casinos Ph. Dissertation. Financial support from the Instituto Valenciano de Investigaciones Económicas, the Ministerio de Ciencia y Tecnología under grant BEC2000-1432 and Fundación BBVAis gratefully acknowledged. We also appreciate the helpful comments of three anonymous referees, whose suggestions improved the paper. Regarding any remaining inadequacies, the usual caveat applies.     

Strategic behavior in financial markets

We describe a financial market as a noncooperative game in strategic form. Agents may borrow or deposit money at a central bank and use the cash available to them in order to purchase a commodity for immediate consumption. They derive positive utility from consumption and from having cash reserves at the end of the day, whereas being bankrupt entails negative utility. The bank fixes interest rates. The existence of Nash equilibria (both mixed and pure) of the ensuing game is proved under various assumptions. In particular, no agent is bankrupt at equilibrium. Asymptotic behavior of replica markets is discussed, and it is shown that given appropriate assumptions, the difference between a strategic player and a price taker is negligible in a large economy.     

Existence of equilibria in economies with externalities and non-convexities in an infinite-dimensional commodity space

We prove an equilibrium existence theorem for economies with externalities, general types of non-convexities in the production sector, and infinitely many commodities. The consumption sets, the preferences of the consumers, and the production possibilities are represented by set-valued mappings to take into account the external effects. The firms set their prices according to general pricing rules which are supposed to have bounded losses and may depend upon the actions of the other economic agents. The commodity space is L_∞(M,M,μ), the space of all μ-essentially bounded M-measurable functions on M.As for our existence result, we consider the framework of Bewley (1972). However, there are four major problems in using this technique. To overcome two of these difficulties, we impose strong lower hemi-continuity assumptions upon the economies. The remaining problems are removed when the finite economies are large enough.Our model encompasses previous works on the existence of general equilibria when there are externalities and non-convexities but the commodity space is finite dimensional and those on general equilibria in non-convex economies with infinitely many commodities when no external effect is taken into account.     

Overlapping Generations or Infinitely-Lived Agents: Intergenerational Altruism and the Economics of Global Warming

Do we need an overlapping generations model for the economics of global warming? To answer this question, an infinitely-lived agent (ILA) approach and an overlapping generations (OLG) model are contrasted. ILA and OLG can be viewed as polar representations of intergenerational altruism. With ILA an immortal agent acts through his investment/savings decisions as trustee on the behalf of the future generations. With OLG, agents need not behave altruistic. They simply save during working years and dissave completely during retirement. Nevertheless, ILA and OLG must not differ in their implication for greenhouse policy. Greenhouse gas abatement is a straightforward alternative to physical capital formation and, even without altruism, each age cohort has an incentive to provide current abatement in order to reduce future damages attributable to climate change. Indeed, under reasonable assumptions and parameter values, our simulations reveal such an invariance result. Provided carbon taxes are the only policy tool and tax revenues are recycled through socially mandated rules, projections of economic growth, climate change and energy consumption are only insignificantly affected by the choice of approach.     

财政分权、制度关联与区域投资格局分析——一个比较制度分析的框架

考虑人口流动性所带来的人力资本的转移效应,建立了一个以财政分权为核心,包含中央政府、地方政府和区域居民三方互动的完整框架,解释了财政分权下我国整体投资格局呈现重物质资本而轻人力资本,并且落后地区更倾向于轻视人力资本投资特征的原因。首先构建了一个多任务委托代理模型分析了政治域中的博弈,然后构建了一个封闭的区域模型分析了组织域中的博弈,基于二者分离解释的不足,进一步对组织域和政治域进行了关联分析。这种比较制度分析框架下基于域之间关联作用的分析表明,以上现象的出现是财政分权下经济分权与政治集权相互矛盾的结果。