Anonymous sequential games: Existence and characterization of equilibria

Summary In this paper we consider Anonymous Sequential Games with Aggregate Uncertainty. We prove existence of equilibrium when there is a general state space representing aggregate uncertainty. When the economy is stationary and the underlying process governing aggregate uncertainty Markov, we provide Markov representations of the equilibria.Table of notation Agents' characteristics space ( ) - A Action space of each agent (aA) - Y Y = x A - Aggregate distribution on agents' characteristics - (X) Space of probability measures onX - C(X) Space of continuous functions onX - _X Family of Borel sets ofX - State space of aggregate uncertainty ( ) - x _t=1 aggregate uncertainty for the infinite game - = (₁,₂,...,_t,...) - ^{t t} (₁, ₂,..., _t) - L₁(^t,C ×A),v _t Normed space of measurable functions from ^t toC( x A) - 8o(^t,( x A)) Space of measurable functions from ^tto( x A) - X^t X^t= x _s=1 ^t X - _X ^t Borel field onX ^t - v Distribution on - v_t Marginal distribution of v on ^t - v(^t)((¦^t)) Conditional distribution on given ^t - v^t(^s)(v_t(¦^s)) Conditional distribution on ^t given ^s (wheres) - _t Periodt distributional strategy - Distributional strategy for all periods =(₁,₂,...,_t,...) - _t Transition process for agents' types - ( _t,^t,y)(P _t+1(, _t , ^t ,y)) Transition function associated with _t - u _t Utility function - V _t (, a, , ^t) Value function for each collection (, a, , ^t ) - W _t (, , ^t ) Value function given optimal action a - C() Consistency correspondence. Distributions consistent with and characteristics transition functions - B() Best response correspondence (which also satisfy consistency) - E Set of equilibrium distributional strategies - x _t=1 ( ^t , (x A)) - S Expanded state space for Markov construction - (, a, ) Value function for Markov construction - P( _t ^* , _t y)(P(, _t ^* , _t , _y )) Invariant characteristics transition function for Markov game We wish to acknowledge very helpful conversations with C. d'Aspremont, B. Lipman, A. McLennan and J-F. Mertens. The financial support of the SSHRCC and the ARC at Queen's University is gratefully acknowledged. This paper was begun while the first author visited CORE. The financial support of CORE and the excellent research environment is gratefully acknowledged. The usual disclaimer applies.     

Equilibria and Pareto optima of markets with adverse selection

Summary This paper examines the efficiency properties of competitive equilibrium in an economy with adverse selection. The agents (firms and households) in this economy exchange contracts, which specify all the relevant aspects of their interaction. Markets are assumed to be complete, in the sense that all possible contracts can, in principle, be traded. Since prices are specified as part of the contract, they cannot be used as free parameters to equate supply and demand in the market for the contract. Instead, equilibrium is achieved by adjusting the probability of trade. If the contract space is sufficiently rich, it can be shown that rationing will not be observed in equilibrium. A further refinement of equilibrium is proposed, restricting agents' beliefs about contracts that are not traded in equilibrium. Incentive-efficient and constrained incentive-efficient allocations are defined to be solutions to appropriately specified mechanism design problems. Constrained incentive efficiency is an artificial construction, obtained by adding the constraint that all contracts yield the same rate of return to firms. Using this notion, analogues of the fundamental theorems of welfare economics can be proved: all refined equilibria are constrained incentive-efficient and all constrained incentive-efficient allocations satisfying some additional conditions can be decentralized as refined equilibria. A constrained incentive-efficient equilibrium is typically not incentive-efficient, however. The source of the inefficiency is the equilibrium condition that forces all firms to earn the same rate of return on each contract.Notation ={ ₁,..., _k } set of outcomes - : ₊ generic contract or lottery - A = () ; - A_o A{, where denotes the null contract or no trade - S={1,...,¦S¦} set of seller types - L(s) number of type-s sellers - M number of buyers - u: × S seller's utility function, which can be extended toA× S by puttingu(, s) ; - v. × S buyer's utility function, which can be extended toA × S by puttingv(, s) ; - f:A ₀ ×S ₊ allocation of sellers - g:A ₀ ×S ₊ allocation of buyers - A ₊ sellers' trading function - :A ×S ₊ buyers' trading function This paper has had a long gestation period, during which I have been influenced by helpful conversations with many persons, by their work, or both. Among those who deserve special mention are Martin Hellwig, Roger Myerson, Edward Prescott, Robert Townsend and Yves Younés. Earlier versions were presented to the NBER/CEME Conference on Decentralization at the University of Toronto and the NBER Conference on General Equilibrium at Brown University. I would like to thank John Geanakoplos, Walter Heller, Andreu Mas Colell, Michael Peters, Michel Poitevin, Lloyd Shapley, John Wooders, Nicholas Yannelis and an anonymous referee for their helpful comments and especially Robert Rosenthal for his careful reading of two drafts. The financial support of the National Science Foundation under Grant No. 912202 is gratefully acknowledged.     

Biological Adaptation in Human Societies: a ‘Basic Needs’ Approach

The groundzero premise (so to speak) of the biological sciences is that survival and reproduction is the basic, continuing, inescapable problem for all living organisms; life is at bottom a survival enterprise. It follows that survival is the paradigmatic problem for human societies as well; it is a prerequisite for any other, more exalted objectives. Although the term adaptation is also familiar to social scientists, until recently it has been used only selectively, and often very imprecisely. Here a more rigorous and systematic approach to the concept of adaptation is proposed in terms of basic needs. The concept of basic human needs has a venerable history – tracing back at least to Plato and Aristotle. Yet the development of a formal theory of basic needs has lagged far behind. The reason is that the concept of objective, measurable needs is inconsistent with the theoretical assumptions that have dominated economic and social theory for most of this century, namely, valuerelativism and cultural determinism. Nevertheless, there have been a number of efforts over the past 30 years to develop more universalistic criteria for basic needs, both for use in monitoring social wellbeing (social indicators) and for public policy formulation. Here I will advance a strictly biological approach to perationalizing the concept of basic needs. It is argued that much of our economic and social life (and the motivations behind our revealed preferences and subjective utility assessments), not to mention the actions of modern governments, are either directly or indirectly related to the meeting of our basic survival needs. Furthermore, these needs can be specified to a first approximation and supported empirically to varying degrees, with the obvious caveat that there are major individual and contextual variations in their application. Equally important, complex human societies generate an array of instrumental needs which, as the term implies, serve as intermediaries between our primary needs and the specific economic, cultural and political contexts within which these needs must be satisfied. An explicit framework of Survival Indicators, including a profile of Personal Fitness and an aggregate index of Population Fitness, is briefly elucidated. Finally, it is suggested that a basic needs paradigm could provide an analytical tool (a biologic) for examining more closely the relationship between our social, economic and political behaviors and institutions and their survival consequences, as well as providing a predictive tool of some value.     

The joint exploitation of a productive asset: a game-theoretic approach

Summary In the present paper we explore the set of equilibria in a game-theoretic model in which players can jointly exploit a productive asset. As in repeated games, we find that under certain circumstances there may be efficient as well as inefficient equilibria. In the model we study, efficient trigger-strategy equilibria may exist from some starting states (stocks of assets) but not others. More precisely, there is a stock level, sayy, such that an efficient trigger-strategy equilibrium exists from starting stocks greater than or equal toy, but not from those strictly less thany. (This statement is meant to include the cases in whichy is zero or infinite.) Under some circumstances, there may exist a new kind of equilibrium, which we call aswitching equilibrium. We show that, in our model, whenever y is positive (and finite), there is an open intervalI with upper endpoint y such that, from any starting stock inI there is an equilibrium of the dynamic game with the following structure: the players follow an inefficient but growing path until the stock reaches the levely, and then follow an (efficient) trigger strategy after that. The use of a continuous-time model enables us to conveniently decouple the delay of information from the time interval between decisions.We thank the C. V. Starr Center at New York University for research support. The views expressed here are those of the authors, and not necessarily those of AT&T Bell Laboratories.     

Public-Choice Analysis of a New International Organization: The International Sea-Bed Authority

The usefulness of the public-choice approach for a better understanding of international organizations can be demonstrated by applying it to the analysis of the structure and functions of a new international organization, the International Sea-Bed Authority, established in 1994, after two decades of negotiations under the auspices of the United Nations, with the aim to control the oceans' mineral resources beyond the limits of national jurisdictions (which have been proclaimed by the U.N. Assembly common heritage of mankind). First, the reasons for establishing this organization, whose basis is the common heritage of mankind nature of ocean resources, are examined under two aspects: 1) definition and protection of property rights; 2) environmental control of sea-bed mining activities. Secondly, the organization's decisionmaking system is presented, including such features as the assembly, council with chamber voting, finance committee with decision by consensus, features that balance the voting power of members and protect those countries that bear the financial responsibility for the budget. Finally, some comments are offered about more general aspects of the theory of international organizations: the bureaucracy (and diplomacy) of these organizations as well as the interdependence among international organizations, which opens the way to forms of international logrolling and makes it advisable for countries not to exit from these organizations, even when they have no primary interest in them.     

The Regulation of Private Schools Serving Low-Income Families in Andhra Pradesh,India

This paper sets out some findings of a research project carried out in private unaided schools in low-income areas of Hyderabad, India. The part of the research project documented here was designed to examine the question: Is the regulatory regime conducive to entrepreneurial action and market discovery with particular reference to the low-income schools in Hyderabad. This paper is narrowly focused, setting out the results of pattern matching empirical data with the Austrian economic concepts of entrepreneurship, rivalry, and market discovery. The research discovered that two regulatory regimes exist, one that is set out on paper in the Education Acts and associated rules, and another that operates in practice. That is, there is a combination of regulations on paper and regulations existing in an extra-legal sector. Generally it was found that the regulations in practice are consistent with market principles. Conversely the regulations set out on paper are not conducive to entrepreneurial innovation and market discovery. Recommendations for potential policy initiatives include the possibility of legitimising the extra-legal sector by introducing self-regulation possibly via self-evaluation systems for the private unaided schools.     

Breeding hybrid strategies: optimal behaviour for oligopolists

Oligopolistic pricing decisions-in which the choice variable is not dichotomous as in the simple prisoner's dilemma but continuous-have been modeled as a generalized prisoner's dilemma (GPD) by Fader and Hauser, who sought, in the two MIT Computer Strategy Tournaments, to obtain an effective generalization of Rapoport's Tit for Tat for the three-person repeated game. Holland's genetic algorithm and Axelrod's representation of contingent strategies provide a means of generating new strategies in the computer, through machine learning, without outside submissions.The paper discusses how findings from two-person tournaments can be extended to the GPD, in particular how the author's winning strategy in the Second MIT Competitive Strategy Tournament could be bettered. The paper provides insight into how oligopolistic pricing competitors can successfully compete, and underlines the importance of niche strategies, successful against a particular environment of competitors.Bootstrapping, or breeding strategies against their peers, provides a means of examining whether repetition leads to cooperation: we show that it can, under certain conditions, for simple and extended two- and three-person GPD repeated games. The paper concludes with a discussion of the relationship between Selten's trembling-hand perfect equilibrium and Maynard Smith's evolutionarily stable strategies, with practical simulations of successful and unsuccessful invasions by new strategies.     

Convergence and approximation results for non-cooperative Bayesian games: Learning theorems

Summary LetT denote a continuous time horizon and {G ^t :tT} be a net (generalized sequence) of Bayesian games. We show that: (i) if {x ^t : tT} is a net of Bayesian Nash Equilibrium (BNE) strategies for G^t we can extract a subsequence which converges to a limit full information BNE strategy for a one shot limit full information Bayesian game, (ii) If {x ^t : tT} is a net of approximate or _t-BNE strategies for the game G^t we can still extract a subsequence which converges to the one shot limit full information equilibrium BNE strategy, (iii) Given a limit full information BNE strategy of a one shot limit full information Bayesian game, we can find a net of _t-BNE strategies {x ^t : tT} in {G ^t :tT} which converges to the limit full information BNE strategy of the one shot game.We wish to thank Larry Blume, Mark Feldman, Jim Jordan, Charlie Kahn, Stefan Krasa, Gregory Michalopoulos, Wayne Shafer, Bart Taub, and Anne Villamil for several useful discussions. The financial support of the University of Illinois at Urbana-Champaign Campus Research Board is gratefully acknowledged.     

Catching-Up Investment without Regulatory Commitment

This paper analyses a regulated firms incentives to undertake catching-up investments when the firm has private information about the initial technology and the regulator is unable to commit himself to incentive contracts prior to the firms investment decision. In the absence of commitment power, the firm takes into account that the investment decision may serve as a signal to the regulator about the firms initial technology. Any pure strategy equilibrium of the signaling game is shown to be pooling in the sense that the efficient type mimics the inefficient type by investing. By not following this strategy, the efficient type reveals its efficiency to the regulator, who responds by inducing the firm to produce without rents. Restricting attention to undefeated pooling equilibria, the level of investment is shown to be lower than the first-best level.     

Strategy-proof and individually rational social choice functions for public good economies

Summary We consider the problem of choosing an allocation in an economy in which there are one private good and one public good. Our purpose is to identify the class of procedures of choosing an allocation which satisfy strategy-proofness, individual rationality, no exploitation and non-bossiness. Any such procedure is a scheme of semi-convex cost sharing determined by the minimum demand principle.I wish to thank Professors Salvador Barbera, Matthew Jackson, Herve Moulin and William Thomson for their helpful suggestions and two anonymous referees for their detailed comments. Conversations with Professors Hideo Konishi, Shinji Oseto Ken-ichi Shimomura and Stephen Ching were helpful. This work is supported by the Japan Economic Research Foundation and Research Grants PB89-0294 and PB89-0075 from the Direcion General de Investigacion Cientifica y Tecnica, Spanish Ministry of Education.     

Are Uniform Solutions Focal? – The Case of International Environmental Agreements

The application of uniform solutions has several drawbacks, notably their lack of cost efficiency and their inability to guarantee individual rationality. A proper specification of uniform solutions, however, reveals that uniform solutions that satisfy individual rationality always exist. When all countries hold private information about their own reduction costs, there only exists one solution that always satisfies individually rationality without use of side payments and the requirement of dominant strategy implementation: The solution that selects the smallest individually preferred uniform reduction which also give a theoretical explanation of the lowest common denominator effect.     

Measuring the trade-off between economic growth and a clean environment

This article surveys various aspects of the measurement of environmental quality from the view point of national accounting and welfare economics. It focuses on the question whether GNP or NNP should be corrected for environmental change (green or eco-GNP) or whether physical accounts provide sufficient information for an assessment of the trade-off mentioned above. We conclude that valuation of (services from) environmental capital cannot be avoided for such assessment, but can only be made using a model based approach. Statistical agencies should continue to collect data on environmental quality and to value changes in environmental capital in the context of national resource accounting. However, official statisticians should refrain from correcting GNP or NNP for environmental change, as this correction implicitly contains a political judgment and cannot be based on mere technical knowledge.     

Should bank branching be regulated? Theory and empirical evidence from four European countries

Along with the liberalisation of bank branching, which was pushed ahead in most OECD member countries during the past several decades, the fear of overbranched markets has arisen. In a model of spatial competition, the welfare effects of bank branching regulation are investigated and empirical results are presented from a pooled cross-section time series analysis from four European countries. It is shown that for all observations in the sample, fewer branches would have been socially undesirable. Moreover, the frequently posed hypothesis that a positive relationship exists between the number of branches and the price for financial intermediation is rejected.     

Institutional Evolution through Purposeful Selection: The Constitutional Economics of John R. Commons

The paper relates John. R. Commons view on the roleof human design in institutional evolution to the views thathave been advanced on this matter by F. A. Hayek, in German ordo-liberalism,and in constitutional political economy. It is argued that Commonsconcept of purposeful selection points in the direction ofa theoretical perspective that consistently integrates the notionsof institutional evolution and constitutional design.     

An evolutionary theory of the convergence towards low inflation rates

This paper presents an evolutionary interpretation of Barro-Gordons monetary policy game. The model describes a multi-country setup where governments and private agents are boundedly rational players. The behavioral rule of players decisions leads to the imitation of the strategy giving the highest payoff. In this evolutionary monetary policy game, we show how a low inflation state is reached from an international context dominated by inflationary policies. The analysis explains the convergence towards low inflation rates observed during the past twenty years. Moreover, the low inflation state appears to be the long-run equilibrium of the game under some conditions featuring the observed macroeconomic context.JEL Classification: E5, C72, C73 Correspondence to: A. dArtigues     

A Damage Based Tax Mechanism for Regulation of Non-Point Emissions

In a recent paper Segerson (1988) proposed a novel incentive mechanism for stochastic non-point emissions based on ambient pollution concentrations in nature. For specification of the mechanism when the damage function is nonlinear, the regulator must know polluters cost and emission functions. The mechanism also gives incentives to form coalitions among polluters, which, if they are formed, render the mechanism inefficient. In this paper we propose a revised mechanism which eliminates the need for knowledge of polluters cost and emission functions and reduces the probability of coalition forming. A standards and pricing version of the revised mechanism with both properties mentioned is also developed.     

Measuring the severity of unemployment

A social-welfare (illfare) function framework is applied to compare two demographic groups as to the severity of their unemployment experience. This is based on the assumption that for each individual the disutility of unemployment is an increasing and convex function of spell length. The very concept of spell length and its distribution, however, is not unambiguous. In contrast to previous literature which focuses exclusively on the interrupted spell length in a stock of unemployed, we stress the usefulness of the concept of complete spell length in a cohort of unemployed. We establish an equivalence relationship between second-degree dominance in the cohort and first-degree dominance in the stock. For specific illfare functions the disutilityU(x) when applied to the cohort and the disutilityU(x) when applied to the stock will produce the same value of aggregate welfare (illfare).     

From Libertinism to Marital Commitment: The Economics of Marital Search with Heterogeneous Agents

Synopsis The actual characteristics and desires of candidates or marriage cannot be clearly identified without careful examination (Anderson & Hamori 2000). Accordingly, the classified advertisement system looks like a market or lemons (Akerlof 1970), which sharply contrasts with the matchmaking agency system. The continued existence of classified advertisement system just proves it furthers the goals of certain singles—namely, libertine females and libertine males. The present paper uses two databases: the first database consists of a sample of personal advertisements extracted from a specialized publication; the second database is the customer file of a matchmaking agency. This paper predicts which variables will determine the commitment level desired by individuals and why matchmaking agencies customers are more sincere than advertisers.     

Endogenous Growth and Natural Resource Scarcity

Endogenous growth theory has rekindled interest in the role of innovation in determining long-term economic growth. Generally, this body of literature has ignored the contribution of natural resources to growth or the role of innovation in overcoming resource scarcities. The latter problem has been a focus of resource economics for many years, but innovation is usually modelled as exogenous rather than endogenous technological change. Recent investigations in political economy have additionally suggested that the supply of innovation may itself be constrained by resource scarcities, especially in the developing world. The following paper attempts to bridge these theoretical gaps through the formal analysis of two issues: First, a simple Romer-Stiglitz model of endogenous growth with resource scarcity and population growth is developed to determine the optimal balanced growth path for the economy. Second, the basic model is extended to allow for the possibility of resource availability constraining the supply of innovation, so that in the long run innovation net of any resource constraint is zero. However, under the latter conditions it is still possible to avoid resource exhaustion and thus achieve a constant level of per capita consumption in the long run. The paper therefore demonstrates that endogenous growth can overcome resource scarcity, but the outcome in the long run depends critically on assumptions concerning any constraints imposed by resource availability on the generation of innovation.     

A New Variant of the Winner's Curse in a Coasian Contracting Game

We examine behavior in a Coasian contracting game with incomplete information. Experimental subjects propose contracts, while automaton property right holders or robot players with uncertain preferences respond to those proposals. The most common pattern of proposals observed in these games results in too many agreements and, in some games, payoffs that are stochastically dominated by those resulting from rational proposals (which imply fewer agreements). In this sense, we observe a winner's curse similar to that observed in bidding games under incomplete information, such as the common value auction (Kagel, J.H. and Levin, D. (1986) American Economic Review. 76, 894–920) and the takeover game (Samuelson, W. and Bazerman, M.H. (1985) In Research in Experimental Economics, Vol. 3. JAI Press, Greenwich, pp. 105–137; Ball, S.B., Bazerman, M.H., and Carroll, J.S. (1990) Organizational Behavior and Human Decision Processes. 48, 1–22; Holt, C. and Sherman, R. (1994) American Economic Review. 84, 642–652). While the naïve model of behavior nicely predicts the winner's curse in those previous bidding games, it does not do so here. Instead, an alternative model we call the guarantor model explains the anomalous behavior best. Hence, we suggest this is a new variant of the winner's curse.