Asymptotic expected number of Nash equilibria of two-player normal form games

The formula given by McLennan [The mean number of real roots of a multihomogeneous system of polynomial equations, Amer. J. Math. 124 (2002) 49–73] is applied to the mean number of Nash equilibria of random two-player normal form games in which the two players have M and N pure strategies respectively. Holding M fixed while N→∞, the expected number of Nash equilibria is approximately . Letting M=N→∞, the expected number of Nash equilibria is , where is a constant, and almost all equilibria have each player assigning positive probability to approximately 31.5915 percent of her pure strategies.     

中国乡城流动人口社会网络复杂性特征分析

借助社会网络等非正式制度方式实现再社会化是乡城流动人口融入城市生活的主要途径之一。对流动人口社会网络的分析不仅可以揭示其网络结构特点,也将为进一步研究流动人口再社会化过程提供理论基础。采用深圳市流动人口专项调查中的整体网络数据,借助复杂性科学,尤其是复杂网络的研究方法,系统分析了乡城流动人口社会支持网络与讨论网络的复杂性特征。在乡城流动人口社会网络中广泛存在小世界现象和无标度特性等复杂网络特征。复杂性科学可以为分析诸如乡城流动人口这样的复杂系统提供有效方法,也是拓展复杂性科学,尤其是复杂网络应用领域的有益尝试。     

民航灾害的复杂性特征探索

民航灾害作为一种高度复杂的社会现象,它具有非线性、多样性、突发性、随机性、整体性、多变性、统计性和屯规律性等复杂性特征.提出将民航灾害看作一个复杂系统,借助分形理论、混沌理论、人工神经网络等复杂性科学的工具,并结合预警管理方法,对民航灾害的复杂性进行探索,初步构造了民航灾害复杂性研究的理论框架.     

Profitability analysis in UK organizations: An exploratory study

Recent research into management accounting practices suggests that companies are now placing considerable emphasis on profitability analysis and consider it to be one of the most important management accounting practices. There is however little recent empirical research relating to the content and role of profitability analysis in companies. This paper will address this omission and report the findings derived from a survey of UK companies relating to information that is contained in profitability reporting, generated for managing the existing mix of a firm's activities. In particular, it focuses on the nature, content and role of profitability analysis carrying out some exploratory analysis and testing various propositions to explain the divergence in observed practices.A distinctive feature of the research is that, unlike some previous research, rather than focusing on the information that is accumulated within the costing system it focuses primarily on the information that is extracted from it for different purposes. Not surprisingly we find that different information is extracted for profitability analysis than for pricing purposes. The research findings also indicate that firms use a hierarchy of profit measures within the periodic profitability analysis statements and that profitability analysis is used mainly for attention-directing purposes for signalling the need for more detailed studies. For profitability analysis, the findings suggest that, in terms of what is considered the most important attention-directing measure, the use of some form of full costs based on arbitrary allocations is not as widespread as that suggested by previous studies. Evidence is also presented to suggest that the level of cost system complexity influences the observed practices.     

Globalization frustrated: The case of white goods

This paper challenges the common view that mature industries are always ripe for global strategies. Based on data from the European Domestic Appliance industry, this paper shows how changing economic conditions can diminish the value of global strategies. Critical in these shifts were simultaneous rises in demand for variety (that eroded the benefits of scale and continental market share) and decreases in manufacturing scale (that permitted new supply options), which reduced the extent of the strategic market to national dimensions. They added complexity that decreased the profitability of the global players and increased that of national strategies. The fluctuating fortunes of leading firms are shown to have been caused primarily by choices of strategy, not by national factor costs.     

企业金融化、内部控制与审计质量

企业金融化在资本市场与金融市场领域的研究比较深入,但学者对企业金融化在审计领域的研究关注较少。以2010—2018年我国A股上市公司为研究样本,实证检验企业金融化对审计质量的影响以及内部控制对两者关系的调节作用。研究发现,企业金融化与审计质量显著负相关,内部控制能显著抑制企业金融化对审计质量的负向影响。进一步研究发现:审计业务复杂程度和审计风险在企业金融化对审计质量的影响中发挥显著的中介效应,即企业金融化通过增加业务复杂程度和审计风险,从而降低审计质量;来自四大的审计师具有更强的专业胜任能力和独立性,且连续审计中,其能更好地利用内部控制以应对企业金融化带来的风险;内部控制五要素中内部监督能显著抑制企业金融化对审计质量的负向影响,而内部环境、风险评价、信息沟通、控制活动均未能显著抑制企业金融化对审计质量的负向影响。研究结论丰富了企业金融化与审计质量领域的相关文献,拓展了企业金融化经济后果的理论边界,同时也为推行建立健全良好的内部控制制度提供了经验证据。     

基于演化博弈论的知识联盟动态复杂性分析

知识联盟是企业间为共同创造知识和进行知识共享而建立的联盟。本文从演化博弈论的角度，探讨了进行知识联盟的企业交互活动的复杂性可能对异质知识流的扩散和知识联盟稳定性造成多重可能结果。分析表明：一个企业实施知识流的更新（如建立知识联盟）和顺利扩散，取决于不同因素的作用，并表现出不同的复杂演化结果。对于已建立知识联盟的企业来说。这些不同的结果会对知识联盟的稳定性产生影响。如果企业最终都达到主动变流知识的策略选择状态，则异质知识得以在企业间扩散，从而强化企业间的知识联盟，但如果企业最终没有达到这一状态，则企业知识联盟的稳定性将被削弱。     

Optimal portfolio allocation under the probabilistic VaR constraint and incentives for financial innovation

We characterize the investor’s optimal portfolio allocation subject to a budget constraint and a probabilistic VaR constraint in complete markets environments with a finite number of states. The set of feasible portfolios might no longer be connected or convex, while the number of local optima increases exponentially with the number of states, implying computational complexity. The optimal constrained portfolio allocation may therefore not be monotonic in the state–price density. We propose a type of financial innovation, which splits states of nature, that is shown to weakly enhance welfare, restore monotonicity of the optimal portfolio allocation in the state-price density, and reduce computational complexity. We are grateful to Ken Kavajecz and seminar participants at Harvard Business School, London School of Economics, Maastrict University, ZEI Bonn, and Danske Bank Symposium on Asset allocation and Value-at-Risk: Where Theory Meets Practice for comments on an earlier version of this paper. We also benefitted from the suggestions of two anonymous referees. Our papers can be downloaded from www.RiskResearch.org.     

Polyhedral Combinatorics in Combinatorial Optimization

Polyhedral combinatorics is a subarea of combinatorial optimization of increasing practical importance. It deals with the application of the theory of linear systems and linear algebra to combinatorial problems. The paper is not intended as a survey on polyhedral combinatorics but it reviews some of the main concepts and proof techniques.     

复杂性科学观下的高科技企业成长机制与成长指数设计

复杂性科学打破了线性、均衡、简单还原的传统范式,开创了一种非线性、演化、复杂系统的新范式。高科技企业的成长由于具有非线性、动态性和自组织等复杂系统的基本特征,更适合于纳入到复杂性科学的新范式中研究。本文从高科技企业成长机制的复杂性特征入手,分析其成长机理,构建高科技企业适应性成长机制模型,并采用成长指数对高科技企业成长性进行评价,试图进行这方面的一些开创性研究。