Common knowledge plays an important role in coordination problems and coordination problems are central to many areas of economic policy. In this paper, I review some common knowledge puzzles culminating in the electronic mail game. These puzzles may seem distant from practical concerns. However, I then argue why insights derived from this literature are useful in interpreting empirical evidence of how people coordinate under uncertainty and in understanding the role of communication in coordinating behaviour.
In a simple model of currency crises caused by creditor coordination failure, we show that bailouts that reduce ex post inefficiency will sometimes create ex ante moral hazard but will sometimes enhance the incentives for governments to take preventative actions. This model helps us understand a debate about the role of the IMF in catalyzing lending to developing countries.
Incomplete information games, local interaction games and random matching games are all special cases of a general class of interaction games (Morris (1997)). In this paper, we use this equivalence to present a unified treatment of arguments generating uniqueness in games with strategic complementarities by introducing heterogeneity in these different settings. We also report on the relation between local and global heterogeneity, on the role of strategic multipliers and on purification in the three types of interaction game.
Incomplete information games, local interaction games and random matching games are all special cases of a general class of interaction games (Morris (1997)). In this paper, we use this equivalence to present a unified treatment of arguments generating uniqueness in games with strategic complementarities by introducing heterogeneity in these different settings. We also report on the relation between local and global heterogeneity, on the role of strategic multipliers and on purification in the three types of interaction game.
In a simple model of currency crises caused by creditor coordination failure, we show that bailouts that reduce ex post inefficiency will sometimes create ex ante moral hazard but will sometimes enhance the incentives for governments to take preventative actions. This model helps us understand a debate about the role of the IMF in catalyzing lending to developing countries.
Keywords: Moral hazard, Financial crisis, International financial architecture, Global games
Common knowledge plays an important role in coordination problems and coordination problems are central to many areas of economic policy. In this paper, I review some common knowledge puzzles culminating in the electronic mail game. These puzzles may seem distant from practical concerns. However, I then argue why insights derived from this literature are useful in interpreting empirical evidence of how people coordinate under uncertainty and in understanding the role of communication in coordinating behaviour.
Keywords: Common knowledge, Coordination, Communication
This paper introduces generalized potential functions of complete information games and studies the robustness of sets of equilibria to incomplete information. A set of equilibria of a complete information game is robust if every incomplete information game where payoffs are almost always given by the complete information game has an equilibrium which generates behavior close to some equilibrium in the set. This paper provides sufficient conditions for the robustness of sets of equilibria in terms of argmax sets of generalized potential functions and shows that the sufficient conditions generalize the existing sufficient conditions for the robustness of equilibria.
This paper introduces generalized potential functions of complete information games and studies the robustness of sets of equilibria to incomplete information. A set of equilibria of a complete information game is robust if every incomplete information game where payoffs are almost always given by the complete information game has an equilibrium which generates behavior close to some equilibrium in the set. This paper provides sufficient conditions for the robustness of sets of equilibria in terms of argmax sets of generalized potential functions and shows that the sufficient conditions generalize the existing sufficient conditions for the robustness of equilibria.
Two games are best-response equivalent if they have the same best-response correspondence. We provide a characterization of when two games are best-response equivalent. The characterizations exploit a dual relationship between payoff differences and beliefs. Some “potential game” arguments (cf. Monderer and Shapley, 1996, Games. Econ. Behav. 14, 124-143) rely only on the property that potential games are best-response equivalent to identical interest games. Our results show that a large class of games are best-response equivalent to identical interest games, but are not potential games. Thus we show how some existing potential game arguments can be extended.
Two games are best-response equivalent if they have the same best-response correspondence. We provide a characterization of when two games are best-response equivalent. The characterizations exploit a dual relationship between payoff differences and beliefs. Some “potential game” arguments (cf. Monderer and Shapley, 1996, Games. Econ. Behav. 14, 124-143) rely only on the property that potential games are best-response equivalent to identical interest games. Our results show that a large class of games are best-response equivalent to identical interest games, but are not potential games. Thus we show how some existing potential game arguments can be extended.
Keywords: Best response equivalence; Duality; Farkas’ Lemma; Potential games