Strategic knowledge sharing in Bayesian games

This paper provides a model for the study of direct, public and strategic knowledge sharing in Bayesian games. We propose an equilibrium concept which takes into account communication possibilities of exogenously certifiable statements and in which beliefs off the equilibrium path are explicitly deduced from consistent possibility correspondences, without making reference to perturbed games. Properties of such an equilibrium and of revised knowledge are examined. In particular, it is shown that our equilibrium is always a sequential equilibrium of the associated extensive form game with communication. Finally, sufficient conditions for the existence of perfectly revealing or non-revealing equilibria are characterized in some classes of games. Several examples and economic applications are investigated.     

Believing in employment discrimination: The case of Forrest Mims,Scientific American,and title VII protection

This article reviews the law regarding Title VII employment discrimination protection from religious discrimination. The issues surrounding the principal legal protection in this regard are explored in the context of a recent controversial case in which an author, Forrest Mims, was not hired as a regular contributor forScientific American magazine, ostensibly because of his belief in the theory of creation over the theory of evolution. The definition of what constitutes a protected religious belief or practice is seen to have expanded over time. However, a belief in creationism is not necessarily seen as being tantamount to a religious belief under present legal interpretation of Title VII. The implications of this finding for future needed Title VII revision are discussed.     

Nash-equilibria in a heterogeneous oligopoly with fuzzy information

We consider a model of an oligopolistic market with heterogeneous firms and products where neither the cost nor the demand functions are common knowledge. Instead, each firm only has some vague ideas about the price strategies adopted by its competitors which is modelled by a fuzzy set. In analogy to the notion of an "equilibrium of actions and beliefs" we define and characterize a generalized Nash-equilibrium and show its existence under general conditions. Furthermore, the impact of the fuzzy information on the equilibrium outcome is analyzed by means of a comparative static analysis within a particular model framework.Received: 28 May 2002, Accepted: 25 December 2002, JEL Classification: D43, D80, L13We wish to thank Bernhard F. Arnold, the editor Murat Sertel , and two anonymous referees for helpful comments. Of course, we are responsible for all remaining errors.     

Corporate Lobbying, Regulatory Conduct and the Porter Hypothesis

Michael Porter, the influential Harvard management guru, has promoted the idea that compliance with stricter environmental regulations can afford secondary benefits to firms through improved product design, innovation, corporate morale and in other ways. Once these secondary benefits are factored, the net cost of compliance is argued to be lower than conventionally thought and may even be negative. Whilst environmental economists have rejected the Porter Hypothesis as being based on excessively optimistic expectations of the likely size of such secondary benefits the underlying ideas do enjoy significant credence in the business community. In the context of a lobbying model of regulatory policy-making we argue that the EPA should change the way it conducts regulatory policy to take account of Porter's views – even if it knows those views to be misguided. The model serves to illustrate the more general point that fashions in management thinking can be expected to impact the optimal conduct of regulatory policy.     

Modelling exchange of probabilistic opinions

Summary. This paper studies how communication or exchange of opinions influences correlation of beliefs. The paper focuses on a situation in which agents communicate with each other infinitely many times without observing data. It is an extension to the ‘Expert Problem’ in Bayesian theory, where the informational flow is asymmetric. Moreover, this paper generalizes the existing literature of communication that employs the common prior assumption (CPA) by allowing for heterogeneous beliefs. Some basic convergence results are shown in contrast with the results obtained under the CPA. Furthermore, several economic implications of the basic results are provided. Received: August 27, 2001; revised version: April 16, 2002 RID="*" ID="*" The results presented in this paper are taken from my Ph.D. thesis at Stanford University. I gratefully acknowledge the inspiration obtained from innumerable discussions with Mordecai Kurz about this subject. Also, I appreciate comments from Kenneth J. Arrow, Peter J. Hammond, Maurizio Motolese, Carsten K. Nielsen, Ho-Mou Wu and the anonymous referee.     

企业多元化的新模式：基于核心能力的虚拟经营

本文研究了企业多元化经营的科学含义，创建了一个二元作用定性模型来论证企业发展到一定阶段多元化经营的必然性，研究了现代企业虚拟经营的背景，含义以及企业深化，培育核心能力与开展虚拟经营之间的本质联系，考察了多元化成功与失败的众多企业案例，当代多元化经营成功的企业大多是基于核心能力的战略相关多元化，而虚拟经营也是核心能力培育，深化的产物，借助于基于核心能力的虚拟经营以实现相关多元化发展，是企业多元化的一条新途径，相对于传统多元化而言，它更具竞争优势。     

Impact of Divergent Consumer Confidence on Option Prices

This paper investigates the impact of divergent consumer confidence on option prices. To model this, we assume that consumers disagree on the expected growth rate of aggregate consumption. With other conditions unchanged in the discrete-time Black–Scholes option-pricing model, we show that the representative consumer will have declining relative risk aversion instead of the assumed constant relative risk aversion. In this case all options will be underpriced by the Black–Scholes model under the assumption of bivariate lognormality. This revised version was published online in June 2006 with corrections to the Cover Date.     

投资者异质后验信念对股票价格影响的实证研究

过度自信程度不同的投资者因消息确认精度差异引起意见分歧,产生异质后验信念,导致投资者对股价高估或者低估。在此基础上,以盈余公告信息作为利好或利空消息,研究不同环境下异质后验信念对我国股票价格的影响。实证结果表明:不管在牛市还是在熊市环境下,异质后验信念均会对股价产生影响,当盈余公告为利好消息时,异质后验信念程度越高,当期股价被高估的程度越显著;当盈余公告为利空消息时,异质后验信念程度越高,当期股价被低估的程度越显著。此外,在盈余公告前投资者就对盈余消息作出了反映,但对好消息与坏消息的反映程度不同。     

Pragmatism, Pedagogy and Philosophy A Model of Thought and Action in Action in Primary Technology and Science Teacher Education

This article reports on one outcome from a three-year study with pre-service primary teachers at Goldsmiths' College, University of London. The purpose of the study was to evaluate the influence of participants' prior educational experience and beliefs about the relationship between design & technology (D&T) and science on their lesson planning for these subjects during school placements. Data from the study support a three-domain model of pre-service teachers' thinking and action. When operating within the pragmatic domain, participants are primarily concerned with survival in the classroom, resulting in short-term planning which may contradict their epistemological and curricular beliefs. In the pedagogical domain, the focus shifts from the pre-service teacher themselves and their immediate survival to the learning potential of the activities they plan. There is evidence that some participants have progressed to operating within a philosophical domain, leading to clasroom practice which reflects and re-conceptualises pre-service teachers' core beliefs about the nature of, and relationship between, D&T and science. This revised version was published online in July 2006 with corrections to the Cover Date.     

异质机构投资者共同持股对所持股公司绩效影响的实证研究

以2010年沪、深股市中同时有证券投资基金和除基金外其他机构投资者持股的682家公司为样本,构建线性回归模型研究了异质机构共同持股条件下,异质机构对公司绩效的影响。最终得出结论：在异质机构共同持股条件下,不论持股比例是否具有优势,证券投资基金对公司绩效均具有显著影响,而其他机构投资者对公司绩效均不具有影响。