Global game

In economics and game theory, global games are games of incomplete information where players receive possibly-correlated signals of the underlying state of the world. Global games were originally defined by Carlsson and van Damme (1993).[1]

The most important practical application of global games has been the study of crises in financial markets such as bank runs, currency crises, and bubbles. However, they have other relevant applications such as investments with payoff complementarities, beauty contests, political riots and revolutions, and any other economic situation which displays strategic complementarity.

Global games in models of currency crises

Stephen Morris and Hyun Song Shin (1998)[2] considered a stylized currency crises model, in which traders observe the relevant fundamentals with small noise, and show that this leads to the selection of a unique equilibrium. This result overturns the result in models of complete information, which feature multiple equilibria.

One concern with the robustness of this result is that the introduction of a theory of prices in global coordination games may reintroduce multiplicity of equilibria (Atkeson, 2001). This concern was addressed in Angeletos and Werning (2006)[3] and Hellwig et al.(2006).[4] They show that equilibrium multiplicity may be restored by the existence of prices acting as an endogenous public signal, provided that private information is sufficiently precise.

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References

Hans Carlsson and Eric van Damme (1993), "Global Games and Equilibrium Selection," Econometrica 61 (5): 989-1018.
Stephen Morris and Hyun Song Shin (1998), "Unique Equilibrium in a Model of Self-Fulfilling Currency Attacks," American Economic Review, 88 (3): 587–97.
George-Marios Angeletos and Ivan Werning (2006), "Crises and Prices: Information Aggregation, Multiplicity, and Volatility," American Economic Review, 96 (5): 1720–36.
Christian Hellwig, Arijit Mukherji and Aleh Tsyvinski (2006), "Self-Fulfilling Currency Crises: The Role of Interest Rates," American Economic Review, 96 (5): 1769-1787.

Topics in game theory
Definitions	Cooperative game Determinacy Escalation of commitment Extensive-form game First-player and second-player win Game complexity Graphical game Hierarchy of beliefs Information set Normal-form game Preference Sequential game Simultaneous game Simultaneous action selection Solved game Succinct game
Equilibrium concepts	Nash equilibrium Subgame perfection Mertens-stable equilibrium Bayesian Nash equilibrium Perfect Bayesian equilibrium Trembling hand Proper equilibrium Epsilon-equilibrium Correlated equilibrium Sequential equilibrium Quasi-perfect equilibrium Evolutionarily stable strategy Risk dominance Core Shapley value Pareto efficiency Gibbs equilibrium Quantal response equilibrium Self-confirming equilibrium Strong Nash equilibrium Markov perfect equilibrium
Strategies	Dominant strategies Pure strategy Mixed strategy Strategy-stealing argument Tit for tat Grim trigger Collusion Backward induction Forward induction Markov strategy
Classes of games	Symmetric game Perfect information Repeated game Signaling game Screening game Cheap talk Zero-sum game Mechanism design Bargaining problem Stochastic game Mean field game n-player game Large Poisson game Nontransitive game Global game Strictly determined game Potential game
Games	Go Chess Infinite chess Checkers Tic-tac-toe Prisoner's dilemma Gift-exchange game Optional prisoner's dilemma Traveler's dilemma Coordination game Chicken Centipede game Volunteer's dilemma Dollar auction Battle of the sexes Stag hunt Matching pennies Ultimatum game Rock paper scissors Pirate game Dictator game Public goods game Blotto game War of attrition El Farol Bar problem Fair division Fair cake-cutting Cournot game Deadlock Diner's dilemma Guess 2/3 of the average Kuhn poker Nash bargaining game Induction puzzles Trust game Princess and Monster game Rendezvous problem
Theorems	Arrow's impossibility theorem Aumann's agreement theorem Folk theorem Minimax theorem Nash's theorem Purification theorem Revelation principle Zermelo's theorem
Key figures	Albert W. Tucker Amos Tversky Antoine Augustin Cournot Ariel Rubinstein Claude Shannon Daniel Kahneman David K. Levine David M. Kreps Donald B. Gillies Drew Fudenberg Eric Maskin Harold W. Kuhn Herbert Simon Hervé Moulin Jean Tirole Jean-François Mertens Jennifer Tour Chayes John Harsanyi John Maynard Smith John Nash John von Neumann Kenneth Arrow Kenneth Binmore Leonid Hurwicz Lloyd Shapley Melvin Dresher Merrill M. Flood Olga Bondareva Oskar Morgenstern Paul Milgrom Peyton Young Reinhard Selten Robert Axelrod Robert Aumann Robert B. Wilson Roger Myerson Samuel Bowles Suzanne Scotchmer Thomas Schelling William Vickrey
See also	All-pay auction Alpha–beta pruning Bertrand paradox Bounded rationality Combinatorial game theory Confrontation analysis Coopetition Evolutionary game theory First-move advantage in chess Game mechanics Glossary of game theory List of game theorists List of games in game theory No-win situation Solving chess Topological game Tragedy of the commons Tyranny of small decisions

Global game

Global games in models of currency crises

References

Further reading