Hostname: page-component-848d4c4894-5nwft Total loading time: 0 Render date: 2024-05-22T14:18:14.966Z Has data issue: false hasContentIssue false

On the Foundations of Nash Equilibrium

Published online by Cambridge University Press:  05 December 2008

Hans Jørgen Jacobsen
Affiliation:
University of Copenhagen

Extract

The most important analytical tool in non-cooperative game theory is the concept of a Nash equilibrium, which is a collection of possibly mixed strategies, one for each player, with the property that each player's strategy is a best reply to the strategies of the other players. If we do not go into normative game theory, which concerns itself with the recommendation of strategies, and focus instead entirely on the positive theory of prediction, two alternative interpretations of the Nash equilibrium concept are predominantly available.

In the more traditional one, a Nash equilibrium is a prediction of actual play. A game may not have a Nash equilibrium in pure strategies, and a mixed strategy equilibrium may be difficult to incorporate into this interpretation if it involves the idea of actual randomization over equally good pure strategies. In another interpretation originating from Harsanyi (1973a), see also Rubinstein (1991), and Aumann and Brandenburger (1991), a Nash equilibrium is a ‘consistent’ collection of probabilistic expectations, conjectures, on the players. It is consistent in the sense that for each player each pure strategy, which has positive probability according to the conjecture about that player, is indeed a best reply to the conjectures about others.

Type
Essays
Copyright
Copyright © Cambridge University Press 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aumann, R. 1987. ‘Correlated equilibrium as an expression of Bayesian rationality’. Econometrica, 55:118CrossRefGoogle Scholar
Aumann, R. 1990. ‘Nash equilibria are not self-enforcing’. In Economic Decision Making: Games, Econometrics and Optimisation. Gabszewicz, J. J., Richard, J.-F., and Wolsey, L. A., (eds.). Elsevier Science Publishers B.VGoogle Scholar
Aumann, R. and Brandenburger, A.. 1991. ‘Epistemic conditions for Nash equilibrium’. Working Paper, 91–042, Harvard Business SchoolGoogle Scholar
Bernheim, B. D. 1984. ‘Rationalizable strategic behavior’. Econometrica, 52:1007–28CrossRefGoogle Scholar
Bernheim, B. D. 1986. ‘Axiomatic characterizations of rational choice in strategic environments’. Scandinavian Journal of Economics, 88:473–88CrossRefGoogle Scholar
Binmore, K. 1987. ‘Modelling rational players, Part I’. Economics and Philosophy, 3:179214CrossRefGoogle Scholar
Brandenburger, A. 1992. ‘Knowledge and equilibrium in games’. Journal of Economic Perspectives, 6:83101CrossRefGoogle Scholar
Brandenburger, A. and Dekel, E.. 1987. ‘Rationalizability and correlated equilibria’. Econometrica, 55:6179CrossRefGoogle Scholar
van Damme, E. 1991. ‘Stability and perfection of Nash equilibrium’. 2nd edn., revised and enlarged. Springer-VerlagCrossRefGoogle Scholar
Fudenberg, D. and Kreps, D. M.. 1994a. ‘Learning in extensive-form games, I: self-confirming equilibria’. Mimeo, Harvard University, Stanford University and Tel Aviv UniversityCrossRefGoogle Scholar
Fudenberg, D. and Kreps, D. M.. 1994b. ‘Learning in extensive-form games, II: experimentation and Nash equilibrium’. Mimeo, Harvard University, Stanford University and Tel Aviv UniversityGoogle Scholar
Harsanyi, J. 1973a. ‘Games with randomly disturbed payoffs: a new rationale for mixed-strategy equilibrium points’. International Journal of Game Theory, 2:123CrossRefGoogle Scholar
Harsanyi, J. 1973b. ‘Oddness of the number of equilibrium points: a new proof’. International Journal of Game Theory, 4:6194CrossRefGoogle Scholar
Hendon, E., Jacobsen, H. J. and Sloth, B.. 1994. ‘Adaptive learning in extensive form games and sequential equilibrium’. Mimeo, Institute of Economics, University of CopenhagenGoogle Scholar
Johansen, L. 1982. ‘On the status of the Nash type of noncooperative equilibrium in economic theory’. Scandinavian Journal of Economics, 84:421–41CrossRefGoogle Scholar
Kandori, M., Malaith, G. J. and Rob, R.. 1993. ‘Learning, mutation, and long run equilibria in games’. Econometrica, 61:2956CrossRefGoogle Scholar
Kreps, D. 1987. ‘Nash equilibrium’. The New Palgrave, Eatwell, J., Milgate, M. and Newman, P. (eds.). MacmillanGoogle Scholar
Krishna, V. 1992. ‘Learning in games with strategic complementarities’. Working Paper, Harvard Business School, 92–073Google Scholar
Luce, D and Raiffa, H.. 1957. ‘Games and decisions’. WileyGoogle Scholar
Milgrom, P. and Roberts, J.. 1990. ‘Rationalizability, learning, and equilibrium in games with strategic complementarities’. Econometrica, 58:1255–78CrossRefGoogle Scholar
Milgrom, P. and Roberts, J.. 1991. ‘Adaptive and sophisticated learning in repeated normal form games’. Games and Economic Behavior, 3:82100CrossRefGoogle Scholar
Pearce, D. G. 1984. 'Rationalizable strategic behavior and the problem of perfection. Econometrica, 52:1029–51CrossRefGoogle Scholar
Rubinstein, A. 1991. ‘Comments on the interpretation of game theory’. Econometrica, 59:909–24CrossRefGoogle Scholar
Weibull, J. 1992. ‘An introduction to evolutionary game theory’. Working Paper. The Industrial Institute for Economic and Social ResearchGoogle Scholar
Young, H. P. 1993. ‘The evolution of conventions’. Econometrica, 61:5784CrossRefGoogle Scholar