In a 2007 paper, “A global game with strategic substitutes and complements”, by Karp, L., I.H. Lee, and R. Mason, Games and Economic Behavior, 60(1), 155-175, an argument is made to show existence of Bayesian-Nash equilibrim in global games that may include both strategic substitutes and complements. This note documents a gap in the proof of that statement and presents an alternative proof for ...

That individuals contribute in social dilemma interactions even when contributing is costly is a wellestablished observation in the experimental literature. Since a contributor is always strictly worse off than a non-contributor the question is raised if an intrinsic motivation to contribute can survive in an evolutionary setting. Applying stochastic evolutionary dynamics we give conditions for...

A learning rule is uncoupled if a player does not condition his strategy on the opponent’s payo¤s. It is radically uncoupled if a player does not condition his strategy on the opponent’s actions or payo¤s. We demonstrate a family of simple, radically uncoupled learning rules whose period-by-period behavior comes arbitrarily close to Nash equilibrium behavior in any …nite two-person game. Keywor...

In this paper, we use p-best response sets—a set-valued extension of p-dominance—in order to provide a new sufficient condition for the robustness of equilibria to incomplete information: if there exists a set S which is a p-best response set with ∑I i=1 pi < 1, and there exists a unique correlated equilibrium μ∗ whose support is in S then μ∗ is a robust Nash equilibrium. © 2005 Published by El...

We view achieving a particular correlated equilibrium distribution for a normal form game as an implementation problem. We show, using a parametric version of the two-person Chicken game and a wide class of correlated equilibrium distributions, that a social choice function that chooses a particular correlated equilibrium distribution from this class does not satisfy the Maskin monotonicity con...

We illustrate, by means of two examples, why assuming the principals offer simple menus (i.e. collections of payoff-relevant alternatives) as opposed to more general mechanisms may preclude a complete characterization of the set of equilibrium outcomes in certain sequential contracting environments. We then discuss how refinements of the solution concept, or enrichments of the menus that allow ...

A Nash equilibrium x of a normal-form game G is essential if any perturbation of G has an equilibrium close to x. Using payoff perturbations, we show that for games that are generic in the set of compact, quasiconcave, and generalized payoff secure games with upper semicontinuous sum of payoffs, all equilibria are essential. Some variants of this result are also established. © 2009 Elsevier Inc...

We develop an evolutionary approach to explain altruistic preferences. Given their preferences, individuals interact rationally with each other. By comparing the success of players with different preferences, we investigate whether evolution favors altruistic or selfish attitudes. The outcome depends on whether the individuals' interactions are strategic complements or substitutes. Altruism and...

For Bertrand duopoly with linear costs, we establish via a single counterexample that: (i) A new monotone transformation of the firms’ profit functions may lead to the supermodularity of transformed profits when the standard log and identity transformations both fail, and (ii) Topkis’s notion of critical sufficient condition for monotonicity of a Bertrand firm’s best-reply correspondence cannot...

We provide easily-verifiable sufficient conditions on the primitives of a Bayesian game to guarantee the existence of a behavioral-strategy Bayes–Nash equilibrium. We allow players’ payoff functions to be discontinuous in actions, and illustrate the usefulness of our results via an example of an all-pay auction with general tie-breaking rules which cannot be handled by extant results. © 2015 El...