Discrete representations of a continuum economy

We consider an atomless economy in which the continuum of agents is represented by a real interval. By dividing the interval and associating to every agent in each subinterval the same initial endowments and preferences, we define sequences of discrete economies as approximations to the initial continuum economy. We obtain convergence results for the core (or, alternatively, for the set of Walrasian allocations) of the continuum economy in terms of the cores of the approximating discrete economies. Finally, we state some counterexamples which provide a boundary for more general results in this framework. Received: 29 December 2000 / Accepted: 28 April 2002 C. Hervés and E. Moreno acknowledge support by Research Grant BEC2000-1388-C04-01 from the Dirección General de Investigación Científica y Técnica (DGICYT), Spanish Ministry of Education.?E. Moreno acknowledges support from the Spanish Ministry of Education through a post-doctoral fellowship in 1997 and from a Training and Mobility of Researchers (E.C.) fellowship in 1998 while visiting Universidade Nova de Lisboa.     

Implementation of the Walrasian correspondence by market games

Abstract. In this paper we present a set of axioms guaranteeing that, in exchange economies with or without indivisible goods, the set of Nash, Strong and active Walrasian Equilibria all coincide in the framework of market games. Received: 25 December 1998 / Accepted: 8 April 2002 We are very grateful to William Thomson for many suggestions. Also we would like to thank comments from J. Alcalde, R. Bhattacharya, C. Herrero, P. Marhuenda, D. Pérez-Castrillo, A. Romero-Medina, T. Shinotsuka, T. Sj?str?m, and A. Villar, an associated editor and an anonymous referee. The first author thanks financial support from DGCYT and Direcció General de Reserca under projects PB98-0870, and SGR2000-00054. The second author wishes to acknowledge financial help from DGCYT under project PB98-0940.     

Exchange-proofness or divorce-proofness? Stability in one-sided matching markets

Two stability concepts for one-sided matching markets are analyzed: Gale-Shapley stability and ξ-stability. The first one applies best to markets where no status quo allocation is considered, whereas the second one is a solution to be used when property rights are allowed. A common problem of existence is shared by both solution concepts. Hence, we study economic environments where this problem does not exist, and present a family of agents’ preferences for which existence is guaranteed for both Gale-Shapley stable and ξ-stable outcomes. This work was finished while the author was visiting Duke University, whose hospitality is gratefully acknowledged. Swveral discussions with Salvador Barberà, Hervé Moulin and Marilda Sotomayor and some advice by an anonymous referee were specially useful. This work is partially supported by Grants PB 92-0590 and PB 93-0938 from the DGICYT, the Spanish Ministery of Educación Ciencia, and the Institut Valencià d’Investigacions Econòmiques.     

Elections and strategic positioning games

We formalize the interplay between expected voting behavior and strategic positioning behavior of candidates as a common agency problem in which the candidates (i.e., the principals) compete for voters (i.e., agents) via the issues they choose and the positions they take. A political situation is defined as a feasible combination of candidate positions and expected political payoffs to the candidates. Taking this approach, we are led naturally to a particular formalization of the candidates' positioning game, called a political situation game. Within the context of this game, we define the notion of farsighted stability (introduced in an abstract setting by Chwe 1994) and apply Chwe's result to obtain existence of farsightedly stable outcomes. We compute the farsightedly stable sets for several examples of political situations games, with outcomes that conform to real-world observations.Received: 18 May 2001, Accepted: 22 January 2002, JEL Classification: C7, D7, D8Myrna H. Wooders: http://www.warwick.ac.uk/fac/soc/Economics/wooders/An earlier version of this paper was completed while the first author was visiting the Department of Economics, University of Exeter. The first author gratefully acknowledges Exeter's support and hospitality. Similarly, the second author gratefully acknowledges the support and hospitality of the Centre for Operations Research and Econometrics (CORE) of the University of Louvain-la-Neuve, Belgium and of the University of Cergy-Pontoise, France. Both authors are indebted to Amrita Dhillon, John Duggan and Gilat Levy for helpful comments about references. Both authors thank an anonymous referee for helpful comments.     

Theϕ-divergence statistic in bivariate multinomial populations including stratification

ϕ-divergence statistics quantify the divergence between a joint probability measure and the product of its marginal probabilities on the basis of contingency tables. Asymptotic properties of these statistics are investigated either considering random sampling or stratified random sampling with proportional allocation and independence among strata. To finish same tests of hypotheses of independence are presented. The research in this paper was supported in part by DGICYT Grants No. PS91-0387 and No. PB91-0155. Their financial support is gratefully acknowledged.     

A decentralized and informationally efficient mechanism realizing fair outcomes in economies with public goods

We present a decentralized mechanism (called Lindahl Egalitarian), which yields Pareto efficient and envy free allocations (i.e. fair outcomes). We show that the mechanism is informationally efficient in general production economies with an arbitrary, but finite, number of private and public goods, and a finite number of agents. The mechanism reduces to the Walrasian mechanism starting from equal wealth when no agent cares about public goods. We also prove that the set of Public Competitive equilibrium allocations (from equal endowments and proportional taxation), and the set of the Lindahl Egalitarian equilibrium allocations are the same. We are grateful to Xavier Calsamiglia and Albert Marcet for helpful conversations, and to A. de la Fuente, I. Macho, and an anonimous referee for useful suggestions. A. Manresa’s research has been supported by the grant CICYT PB90-0172. J. Aizpurua acknowledges financial support from the Government of Navarra.     

Beliefs,payoffs, information: On the robustness of the BDP property in models with endogenous beliefs

Neeman (2004) and Heifetz and Neeman (2006) have shown that, in auctions with incomplete information about payoffs, full surplus extraction is only possible if agents’ beliefs about other agents are fully informative about their own payoff parameters. They argue that the set of incomplete-information models with common priors that satisfy this so-called BDP property (“beliefs determine preferences”) is negligible. In contrast, we show that, in models with finite-dimensional abstract type spaces, the set of belief functions with this property is topologically generic in the set of all belief functions. Our result implies genericity of (non-common or common) priors with the BDP property.     

Implementation of the revenue-maximizing auction by an ignorant seller

In a general auction framework with independent private values, we propose a game, with a simple economic interpretation, that allows to implement the revenue-maximizing auction outcome when the seller ignores the distributions of the different bidders’ valuations. In this detail-free implementation procedure, an ascending-price contest is organized and the winner volunteers a payment to the seller; this payment can then be challenged by another bidder who knows the distribution of the winner’s valuation.Received: 4 June 2003, Accepted: 4 April 2005, We have benefited from comments by seminar participants at the Econometric Society North American Winter Meeting and European Meeting, PURC University of Florida, University of Wisconsin, as well as by two referees and an Associate Editor. The authors also wish to acknowledge the hospitality of IDEI in Toulouse where they started this research. The second author acknowledges the financial support of CRSHC, CIRANO and the Bell University Labs.     

Gamma-minimax estimation of a multivariate normal mean

Summary The mean vector of a multivariate normal distribution is to be estimated. A class Γ of priors is considered which consists of all priors whose vector of first moments and matrix of second moments satisfy some given restrictions. The Γ-minimax estimator under arbitrary squared error loss is characterized. The characterization follows from an application of a result of Browder and Karamardian published in Ichiishi (1983) which is a special version of a minimax inequality due to Ky Fan (1972). In particular, it is shown that within the set of all estimators a linear estimator is Γ-minimax. The authors would like to thank the Deutsche Forschungsgemeinschaft for financial support.     

Optimal money growth in a limited participation model with heterogeneous agents

This paper studies optimal money growth in a cash-in-advance production economy with heterogeneity in patience levels and know-how. We show that the rate of deflation suggested by the Friedman rule is limited by the subjective discount rate of the most patient agent in the economy. The output distortion due to cash-in-advance constraints on firms can completely be eliminated by means of the Friedman rule if and only if firms are run by the most patient agents.Received: 16 August 2003, Accepted: 22 March 2005, JEL Classification: D52, D90, E21, E41, E52Parts of this paper were completed while the first and second authors were visiting the University of York and Princeton University respectively. We are thankful for the hospitality of these institutions. The second author also acknowledges the hospitality and support of Bilkent University that he is currently visiting, the support from the Turkish Academy of Sciences in the framework of the ‘Distinguished Young Scientist Award Program’ (TUBA-GEBIP/2004), the grant awarded by the Scientific and Technical Research Council of Turkey (TUBITAK) under the NATO Science Fellowship Program as well as the support from the Center for Economic Design of Bogaziçi University. This paper was presented in the ERC/METU Second International Conference on Economics, Ankara, September 1998, and at seminars in Bilkent, Bogaziçi and Ohio State Universities. We thank, in particular, Emre Alper, Sumru Altug, Huw Dixon, Tatsuro Ichiishi, Ivan Pastine, Murat Sertel and Alan Sutherland for useful comments. We also thank two anonymous referees for comments and suggestions. The views expressed in this paper are those of the authors and do not necessarily reflect that of the Central Bank of Republic of Turkey.     

Credit market segmentation,essentiality of commodities,and supermodularity

We consider incomplete market economies where agents are subject to price-dependent trading constraints compatible with credit market segmentation. Equilibrium existence is guaranteed when either commodities are essential, i.e, indifference curves through individuals’ endowments do not intersect the boundary of the consumption set, or utility functions are concave and supermodular. The smoothness of mappings representing preferences, financial promises, or trading constraints is not required. Hence, we may include in our framework economies where ambiguity is allowed and agents maximize the minimum expected utility over a set of priors, or where markets include non-recourse collateralized loans.     

Information optimality and Bayesian modelling

The general approach of treating a statistical problem as one of information processing led to the Bayesian method of moments, reference priors, minimal information likelihoods, and stochastic complexity. These techniques rest on quantities that have physical interpretations from information theory. Current work includes: the role of prediction, the emergence of data dependent priors, the role of information measures in model selection, and the use of conditional mutual information to incorporate partial information.     

Feasible implementation of taxation methods

This paper studies implementation of taxation methods in one-commodity environments in which the incomes of the agents are unknown to the planner. Feasibility out of equilibrium imposes that the mechanism depend on the environment. We present two mechanisms. The first one, which requires complete information, implements every taxation method in Nash, strong and coalition-proof equilibrium. The second, where informational requirements are relaxed, implements a large class of consistent and monotone methods in subgame perfect equilibrium. Neither mechanism employs the off-equilibrium devices used by the general theory. Under fully private information no method is implementable. Received: 12 March 1997 / Accepted: 21 July 1998     

Implementing action profiles with sequential mechanisms

In this paper we consider the problem of a principal with many agents who desires to implement a given action profile. Agents observe the actions taken by their colleagues, and this information can be exploited by the principal. Sufficient conditions for implementation under various informational structures are provided. Received: 6 April 1996 / Accepted: 19 April 1998     

信息不对称下金融衍生品市场过度投机成因分析

金融衍生品市场应规避由过度投机导致的风险。从信息不对称角度,分析金融衍生品市场中过度投机的成因;并运用加入可选择风险因素的委托-代理简化模型分析指出在信息不对称下,由于缺少代理人约束机制,导致代理人风险成本不变,最终产生过度投机现象。最后,尝试性地提出我国金融衍生品市场风险防范的具体建议。     

基于联盟链的供应链金融信息安全问题思考

"区块链+供应链金融"管理系统的基本架构对其业务运营、维护和发展至关重要。因此,基于联盟链提出关于供应链金融信息安全的问题思考,分析论证了联盟链底层技术支持下,账户及权限管理、网络环境安全、健康监控及法律效力认证等手段使信息安全风险可防可控,最后从加强技术研发、推动基础设施建设、提升从业人员素质、完善法制建设等多角度提出信息安全管理建议,达到提升区块供应链金融稳定性和运作效率的目的。     

Arbitrage and price revelation with asymmetric information and incomplete markets

This paper deals with the issue of arbitrage with differential information and incomplete financial markets, with a focus on information that no-arbitrage asset prices can reveal. Time and uncertainty are represented by two periods and a finite set S of states of nature, one of which will prevail at the second period. Agents may operate limited financial transfers across periods and states via finitely many nominal assets. Each agent i has a private information about which state will prevail at the second period; this information is represented by a subset S_i of S. Agents receive no wrong information in the sense that the “true state” belongs to the “pooled information” set ∩_iS_i, hence assumed to be non-empty.Our analysis is two-fold. We first extend the classical symmetric information analysis to the asymmetric setting, via a concept of no-arbitrage price. Second, we study how such no-arbitrage prices convey information to agents in a decentralized way. The main difference between the symmetric and the asymmetric settings stems from the fact that a classical no-arbitrage asset price (common to every agent) always exists in the first case, but no longer in the asymmetric one, thus allowing arbitrage opportunities. This is the main reason why agents may need to refine their information up to an information structure which precludes arbitrage.     

论保险业信息化的财务集中管理

信息科技的发展,改变了人类的生存环境和企业的经营管理模式,人类社会正由工业社会向信息社会过渡。企业信息化成为企业在经济信息化和经济全球化时代提高企业核心竞争力的重要手段。财务是企业管理的核心,在企业信息化进程中,财务管理信息化是重点,也是企业信息化的切入点。本文针对我国保险业经营管理的现状,分析财务集中管理的优势,认为保险公司的财务信息化应借助网络技术,建立财务集中管理模式。     

基于地震灾害的应急物流公共信息平台构建

近年来,我国地震灾害频发,主震、余震和次生自然灾害更加重了灾区的受灾状况.针对地震灾害的特殊性,首先对应急物流公共信息平台进行需求分析,然后基于此构建了一个由用户层、执行层、决策支持层、数据层和物理层的总体框架,该框架在执行层创新性地加入了的物流交易支持和突后管理模块,有效地整合社会力量进行救援和监督,综合考虑灾区救援争重建的两个环节.考虑到应急物流信息的标准化规范化的问题,在数据层创新性地加入了多元异构数据处理模块.