矩形板在四角点被支承的弯曲问题

在本文中,我们应用功的互等定理进一步研究了在一集中弯矩作用下四个角点被支承的矩形板的弯曲问题。该法简单、通用。     

Which Extreme Values Are Really Extreme?

We define the extreme values of any random sample of size nfrom a distribution function F as the observations exceedinga threshold and following a type of generalized Pareto distribution(GPD) involving the tail index of F. The threshold is the orderstatistic that minimizes a Kolmogorov-Smirnov statistic betweenthe empirical distribution of the corresponding largest observationsand the corresponding GPD. To formalize the definition we usea semiparametric bootstrap to test the corresponding GPD approximation.Finally, we use our methodology to estimate the tail index andvalue at risk (VaR) of some financial indexes of major stockmarkets.     

公司价值理论与股票定价

经济金融化使现代公司财务理论从以往的边缘地位逐步朝着金融经济学的核心与主流方向发展。公司价值理论作为现代公司财务伯重要组成部分已日臻完善和成熟。我国长期对公司价值理论研究的忽视，不仅是企业落后的深层原因，而且也是影响市场发展重要因素之一，因为股票价值与公司价值直接相关，忽视公司价值而形成的股票价格不仅是不合理的，而且会对股票市场产生不良影响。     

模糊集的清晰性

本文试图从模糊集合的定义、表示法、分解定理三方面,论述模糊数学是建立在清晰集合论基础上的新的数学结构,这对认识模糊数学的基础与本质有着重要意义。     

"科斯定理"与科斯理论的核心思想--读"社会成本问题"

本文所指的"科斯定理"仅限于科斯"第一定理",即"如果交易成本为零,那么无论初始权利如何界定,都可以通过市场交易实现产值最大化"这一基本思想.文章通过对"社会成本问题"一文脉络的简要梳理之后指出,"科斯定理"只是科斯为了讨论外部侵害问题而发展出来的分析方法,但这一思路对于分析和解决我国社会主义市场经济建设中所出现的一些问题具有启发和借鉴意义.     

Equilibrium number of firms and economic welfare in a spatial price discrimination model

We examine welfare implications of the equilibrium number of entering firms in a spatial price discrimination model. In contrast to Salop [Salop, S., 1979. Monopolistic competition with outside goods. Bell Journal of Economics 10, 141–156.], the equilibrium number of firms can be either excessive or insufficient from the normative viewpoint.     

Dictatorial domains

Summary. In this paper, we introduce the notion of a linked domain and prove that a non-manipulable social choice function defined on such a domain must be dictatorial. This result not only generalizes the Gibbard-Satterthwaite Theorem but also demonstrates that the equivalence between dictatorship and non-manipulability is far more robust than suggested by that theorem. We provide an application of this result in a particular model of voting. We also provide a necessary condition for a domain to be dictatorial and use it to characterize dictatorial domains in the cases where the number of alternatives is three. Received: July 12, 2000; revised version: March 21, 2002 RID="*" ID="*" The authors would like to thank two anonymous referees for their detailed comments. Correspondence to: A. Sen     

"内部控制机制+外部控制机制"模式初探 --兼论公司内部控制机制失效理论与解决思路

在国有企业实现公司制改造的过程中,基于所有权与经营权分离和信息不对称的事实,在经营者(受托人)与所有者(委托人)之间,围绕着受托责任关系的确立与解除,存在着固有的利益冲突.公司内部控制机制从公司自身出发,增强"内功",作为缓解这一冲突的有效方式,具有不可忽视的研究必要性和重要性.本文认为要使公司内部控制机制有效,"内部控制机制+外部控制机制"模式可以作为一种选择,文中围绕如何优化内部控制机制的问题,首次提出公司制企业控制机制的有效性定理和"内部控制机制+外部控制机制"模式,从控制论原理角度综述我国现存的公司制企业内部控制机制失效理论(委托-代理理论、产权代表缺位理论、人力资本报酬理论、外部经营环境影响理论、内部人控制财务理论),并按照"内部控制机制+外部控制机制"模式,对各个理论逐一评价,并给出笔者的解决思路.     

排污权交易的经济分析

排污权交易是按照科斯定理而制定的基于市场机制的行之有效的污染控制手段。实行排污权交易的结果是污染的治理主要由边际治理成本较低的企业来完成,从而优化了资源配置,有利于社会总产值的提高。排污权交易便于政府进行污染物的总量控制,有助于推动企业进行污染控制技术的革新,实施清洁生产,也有利于环境保护与经济的协调发展,应尽快在我国推广。     

The invisible hand of Laplace: The role of market structure in price convergence and oscillation

The “invisible hand” of the free market is remarkably effective at producing near-equilibrium prices. This is difficult to quantify, however, in the absence of an agreed model for out-of-equilibrium trade. Short of a fully reductionist model, a useful substitute would be a scaling law relating equilibration time and other market parameters. Even this, however, is missing in the literature.We make progress in this direction. We examine a class of Arrow–Debreu markets with price signaling driven by continuous-time proportional-tâtonnement. We show that the connectivity among the participants in the market determines quite accurately a scaling law for convergence time of the market to equilibrium, and thus determines the effectiveness of the price signaling. To our knowledge this is the first characterization of price stability in terms of market connectivity. At a technical level, we show how convergence in our class of markets is determined by a market-dependent Laplacian matrix.If a market is not isolated but, rather, subject to external noise, equilibrium theory has predictive value only to the extent to which that noise is counterbalanced by the price equilibration process. Our model quantifies this predictive value by providing a scaling law that relates the connectivity of the market with the variance of its prices.