Existence of financial equilibria with restricted participation

We consider a two-date model of a financial exchange economy with finitely many agents having nonordered preferences and portfolio constraints. There is a market for physical commodities at any state today or tomorrow and financial transfers across time and across states are allowed by means of finitely many nominal assets or numéraire assets. We prove a general existence result of equilibria for such a financial exchange economy in which portfolios are defined by linear constraints, extending the framework of linear equality constraints by Balasko et al. (1990), and the existence results in the unconstrained case by Cass (1984, 2006), Werner (1985), Duffie (1987), and Geanakoplos and Polemarchakis (1986). Our main result is a consequence of an auxiliary result, also of interest for itself, in which agents’ portfolio constraints are defined by general closed convex sets and the financial structure is assumed to satisfy a “nonredundancy-type” assumption, weaker than the ones in Radner (1972) and Siconolfi (1989).     

Selection dynamics and adaptive behavior without much information

This paper uses the experimental method to investigate behavior in a coordination game when the information available to subjects is limited to their feasible choices and their experienced payoffs. In the experiment subjects converge to an absorbing state at rates that are orders of magnitude faster than reinforcement learning algorithms, but slower than under complete information. This state is very close to a mutual best response outcome. All cohorts converged to the market statistic predicted by the interior equilibrium regardless of the information conditions or the stability conditions. Eric Battalio programmed the graphical user interface. The National Science Foundation and Texas Advanced Research Program provided financial support. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation or the Texas Advanced Research Program.     

中日韩自由贸易区的贸易流量和福利效应分析:一个局部均衡的校准方法

校准方法作为一种确定数理经济模型中的变量和参数的手段之一,在贸易政策的建模研究中得到广泛的应用.本文以局部均衡为基础,利用中日韩三国自1990～2003年共14年的贸易额及相关数据建立校准模型,并对拟议中的中日韩自由贸易区做出比较静态分析,从产业层面来模拟中日韩自由贸易区建成后所可能带来的福利效应.分析结果表明,中日韩三国建立自由贸易区会增加彼此的国民福利水平,并会对未加入贸易协定的其他东亚国家产生影响.因此,在东亚形成更为广泛的自由贸易安排从区域合作的角度来看是一种更佳的合作方式.     

城市扩展的两个均衡条件及其政策含义

论文认为中国的快速城市化侵占了大量的耕地,是迫使粮食在质量差的土地上生产的重要因素之一,造成了巨大的外部成本,应将其整合到城市扩展的代价中,以提高农业对土地的竞争性,求得城乡之间良好平衡.在这个基础上,还应在市区改造和新区建设之间取得平衡,即边缘地块上地租的净增加值应相等.收取的外部费用要用于土地的农业生产外部不经济性治理.土地管理应城乡整合,包括都市更新与新区建设通盘考虑.论文的研究等价于说,如果做到了如上所迷,那么城市扩展导致的土地价值上升部分就能够覆盖它的社会代价:基础设施建设的投入、拆迁投入、土地生产力建设投入和消除土地的农业生产外部不经济性投入.城市发展用地和农业用地会处在一个比较公平的竞争环境中,取得良好的平衡.     

对我国医药企业自主创新演化机制的分析

自主创新是当前商业界和学术界研究比较热的话题。政府相应地制定了一系列的政策和法规来鼓励企业进行自主创新。在这种背景下,我国的医药企业也积极响应国家的政策进行自主创新。然而,医药企业创新在实际操作中的行动方向差异很大。针对这种差异,笔者将医药企业创新划分成新功能创新和新设计创新两种,并且通过对一系列的数据和资料分析后,发现我国的医药企业的创新并非实质上的自主创新即新功能创新,而是新设计创新。文中对产生这种局面的演化机制进行了分析。     

Technological forecasting at the Korean stock market: A dynamic competition analysis using Lotka–Volterra model

The purpose of this paper is to attempt to analyze the dynamic relationship between the Korean Stock Exchange (KSE) and Korean Securities Dealers Automated Quotation (KOSDAQ), two competing markets at the Korean stock market, in the viewpoint of technological forecasting of competition. The Lotka–Volterra system of equations, one well-known competitive diffusion models, is adopted to represent the competitive situations of the Korean stock market and it is estimated using daily empirical index data of KSE and KOSDAQ during 1997–2001. The results show that there existed a predator–prey relationships between two markets in which KSE acted as a prey for the time being after the emergence of KOSDAQ. This interaction was altered to symbiotic relationship and finally to pure competition relationship. We also perform an equilibrium analysis of the estimated Lotka–Volterra equations. As a result, we find that there is an equilibrium point in a dynamic sense. However, the equilibrium point could be unstable in the latest pure competition relationship.     

从不均衡走向均衡——兼论中国应对美国经济衰退

2006年美国经济进入“软着陆”调整期,美国经济衰退给中国经济调整造成了外在压力,也是一种契机。中国经济高速增长会加剧经济结构的不均衡状态,长期高速增长造成极大财富增长,也出现各种不均衡。只要中国下决心调整经济的内外不均衡,就能够再一次在世界经济衰退中完成自己的结构调整。目前,中国应对美国经济衰退还只是阶段性的调整措施。只有通过扩大内需,才能正真意义上实现由非均衡向均衡转变。