Всего статей в данном разделе : 74
Опубликовано на портале: 25-11-2004Hal R. Varian, James Andreoni Wisconsin Madison - Social Systems Working papers. 1999. No. 18.
We consider a modified Prisoners’ Dilemma game in which each agent can offer to pay the other agent to cooperate. The subgame perfect equilibrium of this two-stage game is Pareto efficient. We examine experimentally whether subjects actually manage to achieve this efficient outcome. We find an encouraging level of support for the mechanism, but also find some evidence that subjects’ tastes for cooperation and equity may have significant interactions with the incentives provided by the mechanism.
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: 28-04-2005John Donald Roberts, Paul R. Milgrom Econometrica. 1990. Vol. 58. No. 6. P. 1255-1277.
We study a class of non-cooperative games that includes many standard oligopoly games,macro economic coordination games, network and production externality games, and others. Forthese games, the sets of rationalizable strategies, pure Nash equilibrium strategies, and correlated equilibrium strategies are non-empty and have identical upper and lower bounds. Also,a large class of dynamic learning processes - including both best-response dynamics and Bayesian learning - lead eventually to behavior that lies between these same bounds. General comparative static and welfare theorems are provided. We study the class of (non-cooperative) supermodular games introduced by Topkis (1979) and further studied by Vives (1988). These are games in which each player's strategy set is partially ordered, the marginal returns to increasing one's strategy rise with increases in the competitors' strategies and, if a player's strategies are multidimensional, the marginal returns to any one component of the player's strategy increase with increases in the other components. The simplest examples of such games arise in oligopoly theory. These include the Cournot duopoly game with a wide range of demand specifications and arbitrary continuous cost functions, Bertrand oligopoly games, R&D racing games, and oligopoly games with endogenous choice of production technologies. Additional applications drawn from industrial organization include the Hendricks-Kovenock (1988) drilling game (in which oil firms decide whether to drill exploratory wells when the information obtained is a public good), network externality games, and certain oligopoly games that arise in connection with the Milgrom-Roberts (1988) model of manufacturing. Other examples include games used to model
Rationalizable Strategic Behavior [статья]
Опубликовано на портале: 30-01-2007B. Douglas Bernheim Econometrica. 2006. Vol. 52. No. 4. P. 1007-1028.
This paper examines the nature of rational choice in strategic games. Although there are many reasons why an agent might select a Nash equilibrium strategy in a particular game, rationality alone does not require him to do so. A natural extension of widely accepted axioms for rational choice under uncertainty to strategic environments generates an alternative class of strategies, labelled "rationalizable." It is argued that no rationalizable strategy can be discarded on the basis of rationality alone, and that all rationally justifiable strategies are members of the rationalizable set. The properties of rationalizable strategies are studied, and refinements are considered.
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.
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.
Reputation and Imperfect Information [статья]
Опубликовано на портале: 31-01-2007David M. Kreps, Robert B. Wilson Journal of Economic Theory. 1982. Vol. 27. No. 2. P. 253-279.
A common observation in the informal literature of economics (and elsewhere) is that is multistage games, players may seek early in the game to acquire a reputation for being tough or benevolent or something else. But this phenomenon is not observed in some formal game-theoretic analyses of finite games, such as Selten's finitely repeated chain-store game or in the finitely repeated prisoners' dilemma. We reexamine Selten's model, adding to it a small amount of imperfect (or incomplete) information about players' payoffs, and we find that this addition is sufficient to give rise to the reputation effect that one intuitively expects.
Sequential Equilibria [статья]
Опубликовано на портале: 31-01-2007David M. Kreps, Robert B. Wilson Econometrica. 1982. Vol. 50. No. 4. P. 863-94.
We propose a new criterion for equilibria of extensive games, in the spirit of Selten's perfectness criteria. This criterion requires that players' strategies be sequentially rational: Every decision must be part of an optimal strategy for the remainder of the game. This entails specification of players' beliefs concerning how the game has evolved for each information set, including information sets off the equilibrium path. The properties of sequential equilibria are developed; in particular, we study the topological structure of the set of sequential equilibria. The connections with Selten's trembling-hand perfect equilibria are given.
Sequentially Optimal Auctions [статья]
Опубликовано на портале: 30-01-2007Daniel R. Vincent, R. Preston McAfee Games and Economic Behavior. 1997. Vol. 18. No. 2.
We examine equlibria in sequential auctions where a seller can post a reserve price but, if the auction fails to result in a sale, can commit keeping the object off the market only for an exogenously fixed period of time. We restrict attention to enviornments where bidders have independent private values and where the support of the bidder types lies strictly above the valuation of the seller. In the case where the seller sells by second price auction in each period, there is a unique perfect Bayesian equilbrium. A form of revenue equivalence is shown. There exists a perfect Bayesian equilibrium of repeated first price auctions with the feature that in every period, the seller's expected revenue from the continuation is the same in either auction mechanism. As the length of time the seller can commit to keeping the object off the market goes to zero, seller expected revenues converge to those of a static auction with no reserve price. As the number of bidders becomes large, the seller expected revenue approaches the revenue from an optimal static auction. We also characterize a parametrized auction game in which the simple equilibrium reserve price policy of the seller mirrors a policy commonly used by many auctioneers.
Опубликовано на портале: 31-01-2007David M. Kreps, In-Koo Cho Quarterly Journal of Economics. 1987. Vol. 102. No. 2. P. 179-221.
Games in which one party conveys private information to a second through messages typically admit large numbers of sequential equilibria, as the second party may entertain a wealth of beliefs in response to out-of-equilibrium messages. By restricting those out-of equilibrium beliefs, one can sometimes eliminate many unintuitive equilibria. We present a number of formal restrictions of this sort, investigate their behavior in specific examples, and relate these restrictions to Kohlberg and Mertens` notion of stability.
Single Crossing Properties and the Existence of Pure Strategy Equilibria in Games of Incomplete Information [статья]
Опубликовано на портале: 30-01-2007Susan Carleton Athey Econometrica. 2001. Vol. 69. No. 4. P. 861-89.
This paper analyzes a class of games of incomplete information where each agent has private information about her own type, and the types are drawn from an atomless joint probability distribution. The main result establishes existence of pure strategy Nash equilibria (PSNE) under a condition we call the single crossing condition (SCC), roughly described as follows: whenever each opponent uses a nondecreasing strategy (in the sense that higher types choose higher actions), a player's best response strategy is also nondecreasing. When the SCC holds, a PSNE exists in every finite-action game. Further, for games with continuous payoffs and a continuum of actions, there exists a sequence of PSNE to finite-action games that converges to a PSNE of the continuum-action game. These convergence and existence results also extend to some classes of games with discontinuous payoffs, such as first-price auctions, where bidders may be heterogeneous and reserve prices are permitted. Finally, the paper characterizes the SCC based on properties of utility functions and probability distributions over types. Applications include first-price, multi-unit, and all-pay auctions; pricing games with incomplete information about costs; and noisy signaling games.
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.
The Bargaining Problem [статья]
Опубликовано на портале: 08-07-2005John Forbes Nash Econometrica. 1950. Vol. 18. No. 2. P. 155-162.
A new treatment is presented of a classical economic problem, one which occurs in many forms, as bargaining, bilateral monopoly, etc. It may also be regarded as a nonzero-sum two-person game. In this treatment a few general assumptions are made concerning the behavior of a single individual and of a group of two individuals in certain economic environments. From these, the solution (in the sense of this paper) of classical problem may be obtained. In the terms of game theory, values are found for the game. См. также: Two-person cooperative games, автор - Джо Нэш.
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: 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.