Symmetry and order in the portfolio allocation problem

Summary. This research studies the role of multivariate distribution structures on random asset returns in determining the optimal allocation vector for an expected utility maximizer. All our conclusions pertain for the set of risk averters. By carefully disturbing symmetry in the distribution of the, possibly covarying, returns, we ascertain the ordinal structure of the optimized allocation vector. Rank order of allocations is also established when a permutation symmetric random vector is mapped into the returns vector through location and scale shifts. It is shown that increased dispersion in the vectors of location and scale parameters benefit, ex-ante, investors as does a decrease in the rank correlation coefficient between the location and scale parameter vectors. Revealed preference comparative static results are identified for the location and scale vectors of asset returns. For most issues addressed, we arrive at much stronger inferences when a safe asset is available. Received: August 8, 2000; revised version: January 8, 2001     

国有经济结构分析与调整对策

国有经济战略调整是中央提出的国有企业改革和发展的重要目标。在计划经济体制向市场经济体制的转轨过程中，国有经济的分布仍不够合理，国有企业在竞争领域仍然占有很大的比重，在经济结构的优化方面仍然存在着一些不容忽视的问题。因此，对这一问题的深入研究，具有重要意义。     

马克思如何实现对黑格尔辩证法的改造

马克思是如何实现对黑格尔辩证法的唯物主义改造的呢?马克思反复强调,黑格尔哲学是一种“头足倒置”的哲学,通过推敲黑格尔和马克思的辩证法思想,本文认为马克思实现对黑格尔辩证法的改造,至少经过了三个倒置:倒置了黑格尔辩证法辩证发展的主体;倒置了黑格尔辩证法辩证发展的中介;倒置了黑格尔辩证法辩证发展的理论结构。     

The division of labour and market structure

Most firms produce most of the time under conditions of substantial economies of scale. The division of labour, according to Adam Smith the mainspring of wealth, is intrinsically an economies of scale phenomenon. Market structure in most industries in characterized by a small number of suppliers and a larger number of customers. I explain this law of small numbers as the equilibrium of two forces: the deconcentration effect of imitation and the market spliting effect of further refinements in the division of labour by innovation. A deconcentrated market creates larger incentives for market splitting (product differentiation) by innovation than a concentrated market. But market splitting raises concentration in the market and it raises the number of different markets in the economy. Before the economies of scale of old products are fully exploited, new products are being offered which again are produced under conditions of economies of scale.     

道家的主体性思想初探

随着科学技术的飞速发展和现代化进程的日益加快,人的主体性问题遇到了前所未有的质疑和挑战,人到底应当高扬主体性还是消解主体性?主体性能够消解吗?本文探讨了道家的主体性思想并分析了这一思想的缺陷及现实意义。     

领导干部在农业结构调整中应强化十种意识

新阶段的农业结构调整,必须适应变化了的新形势.为此,要进一步深化对农业结构调整的认识,牢固树立大农业意识、市场意识、规则意识、品牌意识、科技意识、信息意识、产业意识、工业意识、城镇意识和服务意识.     

Stability and Segregation in Group Formation

This paper presents a model of group formation based on the assumption that individuals prefer to associate with people similar to them. It is shown that, in general, if the number of groups that can be formed is bounded, then a stable partition of the society into groups may not exist. (A partition is defined as stable if none of the individuals would prefer be in a different group than the one he is in.) However, if individuals' characteristics are one-dimensional, then a stable partition always exists. We give sufficient conditions for stable partitions to be segregating (in the sense that, for example, low-characteristic individuals are in one group and high-characteristic ones are in another) and Pareto efficient. In addition, we propose a dynamic model of individual myopic behavior describing the evolution of group formation to an eventual stable, segregating, and Pareto efficient partition. Journal of Economic Literature Classification Numbers: C72, H41.     

建立法人股东为主导的股权治理模式

股权结构是公司治理结构的基础,其设置状况是否合理对公司治理结构的效率有着决定性的影响.文章针对当前上市公司股权治理的弊端,设计出一种股权持有者多元化、股权集中程度分散化的股权结构,并提出我国上市公司应建立以法人股东为主导的治理模式.