超额需求不连续时一般均衡分析的新路径

传统的证明一般均衡存在性的方法都必须以连续的超额需求函数为条件。本文提供一种新方法突破这一局限。一般均衡分析中的个人择优问题是一个非线性规划问题,本文用动态规划方法来处理这一非线性规划问题,从而就克服了不连续超额需求函数带来的困难。运用这一新方法,本文证明了超额需求函数不连续时的存在性。  

Dynamics of a two-sector endogenous growth model with intersectoral knowledge spillovers

In a two-sector endogenous growth model with learning by doing and intersectoral knowledge spillovers, we associate local dynamics with the slope of the excess demand curve for a consumption good. Factor intensity determines the income effect, which governs dynamics. We are grateful to an anonymous referee for his/her helpful comments and suggestions.  

The structure of optimal tariff rates in a large country with market power

We theoretically analyze the optimal tariff problem that arises in a large country with market power. By using a model with more than two traded goods, we derive (1) the condition for optimal import tariff rates to be ranked, and (2) the condition under which the optimum import tariff becomes uniform. These conditions are established in a three-good model and in an N-good model. The results are evaluated on the basis of compensated excess demand elasticity, and hence do not require information on income effects. I would like to thank Tatsuo Hatta, Makoto Okamura, Katsuhiko Suzuki and two anonymous referees for their helpful comments and suggestions.  

The intrinsic fallacy of market mechanism and private property rights in alleviating the tragedy of the commons

ABSTRACT

Economists’ solution to the tragedy of the commons relies on well-defined property rights and competitive market mechanism for limiting individuals’ self-serving, short-sighted actions that result in a dramatic depletion of the common resources. However, this solution implicates a serious threat in terms of sustainability. Recently, deterioration of genetic diversity reached alarming levels, mainly attributed to escalating economic pressure that obliges farmers to shift from local breeds towards more profitable and more productive industrial breeds. This study empirically examines the efficiency of the free market mechanism as a solution to the tragedy of the commons through a unique natural experiment in which a huge demand shock arises regarding sheep. Results robustly show that the free market mechanism can cope with even a very challenging demand shock through the adjustment of prices without any shortage of the commodity. However, this finding does not guarantee that such an outcome is sustainable over the very long term. Analysis of the growth rate of the local sheep breeds population and cross-breed sheep population shows that the trend is overwhelmingly in favour of cross-breeds, thus supporting concerns for a free market mechanism, intrinsically driving the extinction of local sheep breeds, an invaluable genetic resource.  

武汉中心城区生态系统服务额外需求 量化评估——缘起绿色基础设施供需错配

生态系统服务从产生到使用是一个动态流动过程， 分别对应着生态系统服务的供给与需求，然而在城市化过程 中，人口的聚集及绿色基础设施的破碎导致城市生态系统服务 供需失衡极为严重。当生态系统服务供给无法满足需求时，则 存在生态系统服务额外需求。通过量化评估生态系统服务的额 外需求，将为绿色基础设施的精确供给提供决策依据。以武汉 中心城区为例，以街区作为基本单元，选择合适的环境质量标 准作为额外需求阈值，对以下4项生态系统服务额外需求进行 量化评估与空间制图：空气净化、雨洪调节、温度调节和游憩 服务，并采用熵值法求得各项服务的权重，叠加得到综合的生 态系统服务额外需求。最终评估结果可作为武汉中心城区绿色 基础设施优先实施区域与类型的规划依据。  

The demand functions that satisfy the weak axiom of revealed preference and generalized monotonicity

We prove that the individual demand function satisfying the Weak Axiom of Revealed Preference and the excess demand function satisfying the Wald’s Axiom are pseudomonotone_*⁺, a new class of generalized monotonicity. With this new concept, we refine the characterization of Zhou for the individual demand function. In particular, a full characterization for the excess demand functions satisfying the Wald’s Axiom is derived.  

Disaggregation of excess demand and comparative statics with incomplete markets and nominal assets

Summary. We prove that locally, Walras' law and homogeneity characterize the structure of market excess demand functions when financial markets are incomplete and assets' returns are nominal. The method of proof is substantially different from all existing arguments as the properties of individual demand are also different. We show that this result has important implications and is part of a more general result that excess demand is an essentially arbitrary function not just of prices, but also of the exogenous parameters of the economy as asset returns, preferences, and endowments. Thus locally the equilibrium manifold, relating equilibrium prices to these parameters has also no structure. Received: September 17, 1996; revised version: November 7, 1997  

On the characterization of excess demand functions

Summary. In this paper, we give the necessary and sufficient conditions that characterize the individual excess demand function when it depends smoothly on prices and endowments. A given function is an excess demand function if and only if it satisfies, in addition to Walras law and zero homogeneity in prices, a set of first order partial differential equations, its substitution matrix is symmetric and negative semidefinite. Moreover, we show that these conditions are equivalent to the symmetry and negative semidefiniteness of Slutsky matrix, Walras law and zero homogeneity of Marshallian demand functions.Received: 25 November 2002, Revised: 11 March 2004, JEL Classification Numbers: D11.Marwan Aloqeili: I would like to thank an anonymous referee for helpful comments.