Subgame perfect implementation: A full characterization

Moore and Repullo [Subgame perfect implementation, Econometrica 56 (1988) 1191-1220], and Abreu and Sen [Subgame perfect implementation: a necessary and almost sufficient condition, J. Econ. Theory 50 (1990) 285-299] introduce distinct necessary and sufficient conditions for SPE implementation, when the number of players is at least three. This paper closes the gap between the conditions—a complete characterization of the SPE implementable choice rules is provided. The characterization consists of α^*, which strengthens α of Abreu-Sen by adding it a restricted veto-power condition, and the unanimity condition. Under strict preferences α^* is equal to α.     

A simple sufficient condition for strong implementation

In an important step forward Maskin [E. Maskin, Nash equilibrium and welfare optimality, Rev. Econ. Stud. 66 (1999) 23–38] showed that two properties – monotonicity and no veto power – are together sufficient for Nash implementation. In contrast to the vast literature that followed, this characterization has two major advantages: First, it is often easy to verify, and second, it has an elegant and simple interpretation. However, there does not exist a similar condition for social choice correspondences that are implementable in strong equilibrium. All existing characterizations are either hard to verify or apply only to comprehensive preference domains. In this paper we improve the situation by giving one such condition. Moreover, using well-known examples we show that this is a practical tool.     

A procedural condition necessary and sufficient for cyclic social preference

Several variations and generalizations of the Voting Paradox show that social-preference cycles are not peculiar to majority rule. I offer a new generalization that is demonstrably as general as possible: a relaxation of majority rule is necessary for a cycle of any sort and sufficient for a dominant one—given certain background assumptions, few and familiar. In its “Latin square” proof as well as its assumptions, the sufficiency theorem directly generalizes both the Voting Paradox and Sen's Liberal Paradox.     

A new necessary condition for implementation in iteratively undominated strategies

We uncover a new necessary condition for implementation in iteratively undominated strategies by mechanisms that satisfy the “best element property” where for each agent, there exists a strategy profile that gives him the highest payoff in the mechanism. This class includes finite and regular mechanisms. We conclude that either the quasilinearity-like assumptions of available sufficiency results cannot be completely dispensed with or some mechanisms that do not satisfy the best element property must be employed. We term the condition “restricted deception-proofness.” It requires that, in environments with identical preferences, the social choice function be immune to all deceptions, making it then stronger than incentive compatibility. In some environments the conditions for (exact or approximate) implementation by mechanisms satisfying the best element property are more restrictive than previously thought.     

A tight sufficient condition for Radner-Stiglitz nonconcavity in the value of information

This paper deals with the existence of a nonconcavity in the value of information, as was first explained by Radner and Stiglitz [A nonconcavity in the value of information, in: M. Boyer, R.E. Kihlstrom (Eds.), Bayesian Models in Economic Theory, Elsevier Science Publishers, Amsterdam, 1984, pp. 33-52 (Chapter 3)]. After defining infinitesimal information distance variationIIDV, we find that IIDV=0 is sufficient for a zero marginal value of information at the null. This is a condition only on the information structure and in particular is independent of the decision maker's preferences. This condition is tight: when IIDV>0, there exists a payoff function for which the marginal value of information at the null is positive under general assumptions.     

A unified treatment of finite and infinite economies: limited arbitrage is necessary and sufficient for the existence of equilibrium and the core

Summary. A single condition, limited arbitrage, is shown to be necessary and sufficient for the existence of a competitive equilibrium and the core in economies with any number of markets, finite or infinite, with or without short sales. This extends earlier results of Chichilnisky [8] for finite economies. This unification of finite and infinite economies is achieved by proving that in Hilbert spaces limited arbitrage is necessary and sufficient for the compactness of the Pareto frontier. Limited arbitrage has also been shown to be necessary and sufficient for a resolution of the social choice paradox [9], [10], [12], [13], [14]. Received: August 4, 1995; revised version: April 11, 1997     

Limited arbitrage is necessary and sufficient for the existence of a competitive equilibrium with or without short sales

Summary A condition oflimited arbitrage is defined on the endowments and the preferences of the traders in an Arrow-Debreu economy. Theorem 1 establishes thatlimited arbitrage is necessary and sufficient for the existence of a competitive equilibrium in markets with or without short sales. Limited arbitrage bounds utility arbitrages, the diversity of the traders in the economy, and the gains from trade which they can afford from initial endowments (Proposition 2); it is related to but nonetheless different from the no-arbitrage condition used in finance. Theorem 2 establishes that an Arrow — Debreu economy has a competitive equilibrium if and only if every one of its subeconomies withN + 1 traders does, whereN is the number of commodities. Limited arbitrage has been shown elsewhere to be equivalent to the existence of the core [16], to the contractibility of spaces of preferences and to the existence of continuous anonymous social choice rules which respect unanimity [10], [14], [15], [16].This paper was circulated in December 1991 as a Working Paper of the Department of Economics, Columbia University, New York, and presented at seminars at Mathematics, Economics, and Operations Research Departments at Columbia, Harvard, Stanford University of California at Berkeley, University of Bonn and the University of Siena, at an invited presentation at the European Congress of Mathematicians, July 1992, and the Winter Meetings of the Econometric Society in Boston, January 1994. Valuable comments and suggestions from Roko Aliprantis, Masahiko Aoki, Kenneth Arrow, Duncan Foley, Geoffrey Heal, Lionel McKenzie, Paul Milgrom and two anonymous referees, and research support from NSF Grant No. 92-16028 and the Stanford Institute for Theoretical Economics are gratefully acknowledged.     

Technological condition for balanced growth: A criticism and restatement

According to prevailing opinion, only the neutral form of technological progress in the Harrod sense is consistent with balanced growth in a one-sector constant returns-to-scale economy. Though various definitions of balanced growth are in use in the literature, the above highly restrictive technological condition is believed to hold for all of them. The paper demonstrates that this belief is not correct. The condition is shown to be false if the definition of balanced growth (i) does not require the constancy of the marginal product of capital (or the interest rate), and (ii) permits the time semiinfinite or indeed any finite balanced growth path. More specifically, under (i) and (ii) there exists a balanced growth path consistent with a significantly wide class of technological changes of the capital-using (labour-saving) form in the Harrod sense. Alternatively, this condition is correct if either (i) the interest rate is required to be constant or (ii) growth is balanced if it is such for all time—that is, for both past and future. The condition is also correct if the socioeconomic institutions are such that the constancy of the savings ratio implies the constancy of the capital share.     

A globally flexible,quadratic almost ideal demand system: an application to demand for meats and fish in Taiwan

A new demand system, called a globally flexible, quadratic almost ideal demand system (GF–QUAIDS), integrates both the quadratic Engel curve and the Fourier series. This novel GF–QUAIDS model is applied to study the demand for meats and fish in Taiwan. Empirical results show that the GF–QUAIDS fits the data well and that, by using the likelihood ratio test, its nested models are rejected, including the locally flexible functional form and the linear Engel curve. Nevertheless, other empirical model-selection measures indicate that the GF–QUAIDS can be as good as its famous nested models such as the AIDS, QUAIDS and GF–AIDS.     

Global stability condition on the plane: A general law of demand

It is well known that global stability of competitive equilibrium obtains only under quite stringent restrictions. This paper identifies a set of restrictions which may be interpreted as a very weak form of the so-called Law of Demand and shows how this may imply global stability for motion on the plane. It is also of some interest that this condition is satisfied by a perturbed version of the celebrated Scarf example which does not satisfy existing conditions for global stability.     

Price cap regulation: A case study of some pitfalls of implementation

There has been considerable discussion of price-cap regulation as an alternative to traditional rate-of-return regulation. This paper examines some of the practical pitfalls of price-cap regulation. First, a model of a terminating price cap is developed. Next, this model is used to propose some problems of implementation. These problems are evaluated in the context of a case study of the Tucson Electric Power Company, which faced a type of price cap for several years in the 1980s. Extensions of the specific case to more general lessons about price-cap regulation are considered.     

Dealing with the dynamics of technology roadmapping implementation: A case study

Nowadays, companies are facing many challenges. The product life cycle is getting shorter while the complexity and the demand for product customization are increasing. Technology Roadmapping (TRM) has been widely used as a strategic management tool to help organizations in effectively identifying potential products or services for the future, determining proper technology alternatives, and mapping them with resource allocation plans. With the completion of TRM implementation, any organization can be assured that its required technologies and infrastructures will be ready when needed. Implementing TRM as a part of the ongoing strategic/business planning process is challenging because it may affect the organizational work process, structure, and culture. Therefore, an organization needs to understand how the changing roles and responsibilities of key players involved in the TRM process match with the dynamics of TRM implementation in each stage. This paper illustrates the dynamics of TRM implementation and presents a case study to demonstrate how one of the leading building product manufacturers in the ASEAN region went through the process.     

Citations,journal ranking and multiple authorships reconsidered: evidence from almost one million articles

In this article, we reconsider the investigation by Moosa (2016) using a much larger data set of almost one million articles listed in Research Papers in Economics. This article provides new insights into the effects of co-authorship on citation counts and the correlation between quality of papers and quality of the publishing journal. Our evidence is partially in contrast to the results reported in Moosa (2016). We find a positive correlation between the h-index of a journal and the quality of papers measured in terms of citations. This correlation becomes almost perfect using a nonlinear model. Results from a regression of citation counts on the number of authors show evidence of a positive and significant effect of co-authorship on the quality of a paper when time effects and large sets of top-cited articles are taken into account. The inclusion of time effects and the large data set, that allows to differentiate between top-cited cohorts, adds further insights to the existing literature.     

Necessary and sufficient conditions in merger control: the use of HHI and threshold value

This article considers two coarse measures applicable to antitrust policy: one of market concentration, the Herfindahl–Hirschman Index (HHI) and one of market dominance, threshold value. Calculations of threshold value are compared to HHI values to determine when thresholds might be of specific use in merger cases. Many scenarios which satisfy the threshold conditions (indicating a dominant firm exists) are consistent with high HHI numbers such that current US Department of Justice and European Commission guidelines (based on HHIs) for merger concerns will have been met. It is suggested as a rule of thumb that HHIs be used as necessary conditions and threshold value be considered sufficient conditions for further case review.     

"走出去"战略:完善政策加快实施

世界经济全球化的趋势正日益深化和加强,“走出去”战略恰恰顺应了这一大趋势,它将进一步推动我国对外开放持续健康发展。从微观层面讲,“走出去”战略亦可称为国际化经营战略,实施主体是各类企业。但从宏观层面讲,“走出去”不仅是企业战略,更是国家战略,中国通过进一步扩大对外开放,利用国内外两个市场和两种资源,更大程度地参与国际分工和国际市场竞争。“走出去”战略主要分为两个层次:第一个层次是对外直接投资,或称为境外投资。第二个层次是国际工程承包与合作,包括对外工程承包和对外劳务合作。实施“走出去”战略就是鼓励和支持有比…     

Interest requirements and its implementation of core stakeholders of heritage resorts:A case study of Jiuzhaigou

The reformation of Heritage resorts management system is to establish a balance of interest mechanism that we must first be able to meet the Heritage resorts core stakeholders interest demands.The article takes the World Heritage resorts Jiuzhaigou as an example,offering an approach of twodimensional management objectives to identify its core stakeholders,studing the interest demands and its implementation from an empirical perspective.The results show that heritage resorts involves a number of stakeholders with complex relationships in the tourism development; different heritage resorts with different core stakeholders; different core stakeholders with specific interest demands,the methods to meet their demand are different as well.     

浅析合作学习的基本内涵、原则和实施方法

本文旨在与同行们共同探讨合作学习的一些基本内涵和实施方法,以便于我们广大教育工作者能够更好地提高对合作学习的认识,能够因地制宜的进行合作学习研究与实验,使教学活动更富有创意性和实效性。     

A simple proof of Ekeland and Scheinkman's result on the necessity of a transversality condition

Summary. Ekeland and Scheinkman (1986) prove the necessity of a standard transversality condition under certain technical conditions. Their result is one of the most powerful on the necessity of a transversality condition currently available in the literature, and their proof involves numerous estimations and relies on Ekeland's variational principle and Fatou's lemma. This note relaxes some of their assumptions and provides a simple proof that uses neither Ekeland's principle nor a convergence result like Fatou's lemma. Received: April 24, 1998; revised version: September 8, 1998     

Countermeasures of adaptation to climate change： establishment and application for implementation matrix

In the conceptual framework of adaptation policy assessment to climate change, adaptation measures can be categorized as two groups：facilitation and implementation. Facilitation measures refers to activities that enhance adaptive capacity, while implementation refers to activities that actually avoid adverse climate impacts on a system by reducing its exposure or sensitivity to climatic hazards, or by moderating relevant non-climatic factors. This paper aims to establish a matrix of implementation measures of adaptation to climate change, through four different ways how adaptation can influencc the relevant elements of climate change. reducing the exposure, reducing the sensitivity, alleviating the adverse impacts and reducing the negative non-climatic factors, and then further discuss the particular implementation measures of adaptation to climate change, through application studies on the selected sub-systems, intend to organize the disordered implementation measures in existent, and put forward some new measures under the guidance of this matrix, which could enrich and promote the system and content of implementation measures of adaptation.