Всего публикаций в данном разделе: 136
Опубликовано на портале: 30-01-2007Eric van Damme, Hans Carlsson Econometrica. 1993. Vol. 61. No. 5. P. 989-1018.
A global game is an incomplete information game where the actual payoff structure is determined by a random draw from a given class of games and where each player makes a noisy observation of the selected game. For 2 x 2 games, it is shown that, when the noise vanishes, iterated elimination of dominated strategies in the global game forces the players to conform to J. C. Harsanyi and R. Selten's risk dominance criterion.
Games Played Through Agents [статья]
Опубликовано на портале: 30-01-2007Aldo Rustichini, Andrea Prat Econometrica. 2003. Vol. 71. No. 4. P. 989-1026.
We introduce a game of complete information with multiple principals and multiple common agents. Each agent makes a decision that can affect the payoffs of all principals. Each principal offers monetary transfers to each agent conditional on the action taken by the agent. We characterize pure-strategy equilibria and we provide conditions-in terms of game balancedness-for the existence of an equilibrium with an efficient outcome. Games played through agents display a type of strategic inefficiency that is absent when either there is a unique principal or there is a unique agent.
Опубликовано на портале: 30-01-2007Muhamet Yildiz Econometrica. 2003. Vol. 71. No. 3. P. 793-811.
In sequential bargaining models without outside options, each player's bargaining power is ultimately determined by which player will make an offer and when. This paper analyzes a sequential bargaining model in which players may hold different beliefs about which player will make an offer and when. Excessive optimism about making offers in the future can cause delays in agreement. The main result states that, despite this, if players will remain sufficiently optimistic for a sufficiently long future, then in equilibrium they will agree immediately. This result is also extended to other canonical models of optimism.
Strategic Information Transmission [статья]
Опубликовано на портале: 24-01-2007Vincent P. Crawford, Joel Sobel Econometrica. 1982. Vol. 50. No. 6. P. 1431-1451.
This paper develops a model of strategic communication, in which a better-informed Sender (S) sends a possibly noisy signal to a Reciever (R), who then takes an action that determines the welfare of both. We characterize the set of Bayesian Nash equilibria under standart assumptions, and show that equilibrium signaling always takes a strikingly simple form, in which S partitions the support of the (scalar) variable that represents his private information and introduces noise into his signal by reporting, in effect, only which element of the partition his observation actually lies in. We show under further assumptions that before S observes his private information, the equilibrium whose partition has the greatest number of elements is Pareto-superior to all other equilibria, and that if agents coordinate on this equilibrium, R`s equilibrium expected utility rises when agents` preferences become more similar. Since R bases his choice of action on rational expectations, this establishes a sense in which equilibrium signaling is more informative when agents` preferences are more similar.
Опубликовано на портале: 24-01-2007Dilip Abreu, Paul Robert Milgrom, David Pearce Econometrica. 1991. Vol. 59. No. 6. P. 1713-1734.
In a repeated partnership game with imperfect monitoring, we distinguish among the effects of (1) reducing the interest rate, (2) shortening the period over which actions are held fixed, and (3) shortening the lag with which accumulated information is reported. All three changes are equivalent in games with perfect monitoring. With imperfect monitoring, reducing the interest rate always increases the possibilities for cooperation, but the other two changes always have the reverse effect when the interest rate is small.
The Evolution of Walrasian Behavior [статья]
Опубликовано на портале: 24-01-2007Fernando Vega-Redondo Econometrica. 1997. Vol. 65. No. 2. P. 375-384.
This article describes an evolutionary approach to understanding Walrasian behavior. It avoids any considerations related to the absence of monopoly power or related notion of a large enough population. Walrasian behavior may evolve within any quantity-setting oligopoly producing a homogenous good, provided that the law of demand is satisfied. Evolutionary models may produce interesting behavior that does not correspond to a Nash equilibrium.
Опубликовано на портале: 24-01-2007Roger B. Myerson International Journal of Game Theory. 1978. Vol. 7. No. 2. P. 73-80.
Selten's concept of perfect equilibrium for normal form games is reviewed, and a new concept of proper equilibrium is defined. It is shown that the proper equilibria form a nonempty subset of the perfect equilibria, which in turn form a subset of the Nash equilibria. An example is given to show that these inclusions may be strict.
Опубликовано на портале: 24-01-2007Jean-François Mertens, Elon Kohlberg Econometrica. 1986. Vol. 54. No. 5. P. 1003-1037.
A basic problem in the theory of noncooperative games is the following: which Nash equilibria are strategically stable, i.e. self-enforcing, and does every game have a strategically stable equilibrium? We list three conditions which seem necessary for strategic stability - backwards induction, iterated dominance, and invariance - and define a set-valued equilibrium concept that satisfies all three of them. We prove that every game has at least one such equilibrium set. Also, we show that the departure from the usual notion of single-valued equilibrium is relatively minor, because the sets reduce to points in all generic games.
Опубликовано на портале: 24-01-2007Robert J. Aumann, Adam Brandenburger Econometrica. 1995. Vol. 63. No. 5. P. 1161-1180.
Sufficient conditions for Nash equilibrium in an n-person game are given in terms of what the players know and believe - about the game, and about each other's rationality, actions, knowledge, and beliefs. Mixed strategies are treated not as conscious randomizations, but as conjectures, on the part of other players, as to what a player will do. Common knowledge plays a smaller role in characterizing Nash equilibrium than had been supposed. When n=2, mutual knowledge of the payoff functions, of rationality, and of the conjectures implies that the conjectures form a Nash equilibrium. When n (greater than or equal to) 3 and there is a common prior, mutual knowledge of the payoff functions and of rationality, and common knowledge of the conjectures, imply that the conjectures form a Nash equilibrium. Examples show the results to be tight.
Опубликовано на портале: 24-01-2007Eric S. Maskin Review of Economic Studies. 1999. Vol. 66. No. 1. P. 23-38.
If is a set of social alternatives, a social choice rule (SCR) assigns a subset of A to each potential profile of individuals' preferences over A, where the subset is interpreted as the set of 'welfare optima.' A game form (or 'mechanism') implements the social choice rule if, for any potential profile of preferences, (1) any welfare optimum can arise as a Nash equilibrium of the game form (implying, in particular, that a Nash equilibrium exists) and, (2) all Nash equilibria are welfare optimal. The main result of this paper establishes that any SCR that satisfies two properties - monotonicity and no veto power--can be implemented by a game form if there are three or more individuals. The proof is constructive.
Опубликовано на портале: 24-01-2007Andrew Weiss Journal of Political Economy. 1983. Vol. 91. No. 3. P. 420-442.
This paper presents a sorting model of education in with individuals are tested in school. By assuming that higher-ability individuals are more likely to succeed on a given test one can construct a sorting model of education that does not hinge on the more able having lower nonpecuniary costs of schooling. Nash equilibria always exist in this model (even with a continuum of types of individuals); however, some are "unreasonable." To eliminate these unreasonable Nash equilibria, more restrictive definitions of equilibrium are proposed. I also show that when schooling affects productivity - and therefore a worker's probability of passing the test--a sorting equilibrium may be characterized by too little investment in education. This paper extends the important work of Spence (1974), Stiglitz (1975), and Riley (1979a, 1979b) on sorting theories of education by modeling the educational choices of individuals in game-theoretic terms and making two assumptions: (1) individuals are not perfectly informed about their own productivity, and (2) individuals are tested upon their completion of schooling. I also combine the sorting and human capital analyses by allowing education to increase productivity and show that if education increases the productivity of workers as well as enabling the more able workers to sort themselves, these sorting effects may lead to underinvestment in education. This result contradicts the main normative result of screening models of education: If skills are hierarchical, so that if Joe is more productive than Jim at any job he is more productive at all jobs, there is overinvestment in schooling as workers use education to signal their abilities. Although in a pure sorting model education always leads to overinvestment in education while human capital models lead to optimal investment, when both effects are modeled there may be too little investment in education. This result holds even if the more able learn faster in school.
Опубликовано на портале: 24-01-2007John Hillas Econometrica. 1990. Vol. 58. No. 6. P. 1365-1390.
A new definition of strategic stability is shown to satisfy all of the requirements given by Elon Kohlberg and Jean-Francois Mertens (1986). The definition follows the general form of the original definition of Kohlberg and Mertens, but, rather than working with perturbations of the payoffs or strategy space, works directly with perturbations to the best reply correspondence. With the appropriate topology on this space of perturbations, the resulting definition does satisfy all of the requirements given by Kohlberg and Mertens. It is shown that one does not have much freedom in the topology one uses.
Опубликовано на портале: 22-01-2007Eric S. Maskin, Partha Sarathi Dasgupta Review of Economic Studies. 1986. Vol. 53. No. 1. P. 1-26.
The article presents information about the existence of equilibrium in discontinuous economic games. In this paper and its sequel presents study the existence of Nash equilibrium in games where agents' payoff functions are discontinuous. The enquiry is motivated by a number of recent studies that have uncovered serious existence problems in seemingly innocuous economic games. In the sequel to this paper, authors have explained the utility function in the economic games referred to earlier are neither continuous nor quasi-concave. However, they demonstrate that the payoff functions in mildly modified versions of these constructs exhibit two weaker forms of continuity which, together with the requirement of quasi-concavity, suffice for the existence of an equilibrium. From this one may conclude that, at least in the modified versions of these models, discontinuities in the payoff functions are not the real source of the problem. Rather, it is the failure of the payoff functions to the quasi-concave which is "responsible" for the non-existence of equilibrium. These observations bear on the existence of Nash equilibrium in pure strategies.
Опубликовано на портале: 22-01-2007Paul Robert Milgrom, Donald John Roberts Journal of Political Economy. 1986. Vol. 94. No. 4. P. 796-821.
We present a signaling model, based on ideas of Phillip Nelson, in which both the introductory price and the level of directly "uninformative" advertising or other dissipative marketing expenditures are choice variables and may be used as signals for the initially unobservable quality of a newly introduced experience good. Repeat purchases play a crucial role in our model. A second focus of the paper is on illustrating an approach to refining the set of equilibria in signaling games with multiple potential signals.
Опубликовано на портале: 22-01-2007Dilip Abreu, Hitoshi Matsushima Econometrica. 1992. Vol. 60. No. 5. P. 993-1008.
The authors investigate the implementation of social choice functions that map to lotteries over alternatives. They require virtual implementation in iteratively undominated strategies. Under very weak domain restrictions, they show that if there are three or more players, any social choice function may be so implemented. The literature on implementation in Nash equilibrium and its refinements is compromised by its reliance on game forms with unnatural features (for example, "integer games") or "modulo" constructions with mixed strategies arbitrarily excluded. In contrast, the authors' results employ finite (consequently "well-behaved") mechanisms and allow for mixed strategies.
Опубликовано на портале: 22-01-2007Roger B. Myerson, Mark A. Satterthwaite Journal of Economic Theory. 1981. Vol. 29. No. 2.
We consider bargaining problems between one buyer and one seller for a single object. The seller's valuation and the buyer's valuation for the object are assumed to be independent random variables, and each individual's valuation is unknown to the other. We characterize the set of allocation mechanisms that are Bayesian incentive compatible and individually rational, and show the general impossibility of ex post efficient mechanisms without outside subsidies. For a wide class of problems we show how to compute mechanisms that maximize expected total gains from trade, and mechanisms that can maximize a broker's expected profit.
Опубликовано на портале: 22-01-2007Edward Green, Robert H. Porter Econometrica. 1984. Vol. 52. No. 1. P. 87-100.
Recent work in game theory has shown that, in principle, it may be possible for firms in an industry to form a self-policing cartel to maximize their joint profits. This paper examines the nature of cartel self-enforcement in the presence of demand uncertainty. A model of a noncooperatively supported cartel is presented, and the aspects of industry structure which would make such a cartel viable are discussed.
Опубликовано на портале: 22-01-2007Ehud Lehrer, Ehud Kalai Econometrica. 1993. Vol. 61. No. 5. P. 1019-1045.
Subjective utility maximizers, in an infinitely repeated game, will learn to predict opponents' future strategies and will converge to play according to a Nash equilibrium of the repeated game. Players' initial uncertainty is placed directly on opponents' strategies and the above result is obtained under the assumption that the individual beliefs are compatible with the chosen strategies. An immediate corollary is that, when playing a Harsanyi-Nash equilibrium of a repeated game of incomplete information about opponents' payoff matrices, players will eventually play a Nash equilibrium of the real game, as if they had complete information.
Optimal Auction Design [статья]
Опубликовано на портале: 22-01-2007Roger B. Myerson Mathematics of Operations Research. 1978. Vol. 6. No. 1. P. 58-73.
This paper considers the problem faced by a seller who has a single object to sell to one of several possible buyers, when the seller has imperfect information about how much the buyers might be willing to pay for the object. The seller's problem is to design an auction game which has a Nash equilibrium giving him the highest possible expected utility. Optimal auctions are derived in this paper for a wide class of auction design problems.
Опубликовано на портале: 22-01-2007Hugo F. Sonnenschein, Faruk Gul Econometrica. 1988. Vol. 56. No. 3. P. 601-611.
Recently, attention has been given to a model of two-person bargaining in which the parties alternate making offers and there is uncertainty about the valuation of one party. The purpose of the analysis has been to identify delay to agreement with a screening process, where agents with relatively lower valuations distinguish themselves by waiting longer to settle. We point out a fundamental difficulty with this program by demonstrating that the assumptions used in the literature allow for delay only in so far as the time between offers is significant.