Aumann has shown that agents who have a common prior cannot have common knowledge of their posteriors for event $E$ if these posteriors do not coincide. But given an event $E$, can the agents have posteriors with a common prior such that it is common knowledge that the posteriors for $E$...

This chapter is a very compressed review of the neoclassical orthodoxy on the nature of rationality on economic theory. It defends the orthodoxy both against the behavioral criticism that it assumes too much and the revisionist view that it assumes too little. In places, especially on the...

We define a generalized state-space model with interactive unawareness and probabilistic beliefs. Such models are desirable for many potential applications of asymmetric unawareness. We develop Bayesian games with unawareness, define equilibrium, and prove existence. We show how equilibria are...

We study communication in ambiguous environments. Agents communicate individual decisions sequentially. Based on the signal that an agent receives, she revises her private information. When signals are ambiguous, we show that agents may agree to disagree forever. Although the learning process...

We define and analyze a "strategic topology'' on types in the Harsanyi-Mertens-Zamir universal type space, where two types are close if their strategic behavior is similar in all strategic situations. For a fixed game and action define the distance between a pair of types as the difference...

This paper proposes the solution concept of interim correlated rationalizability, and shows that all types that have the same hierarchies of beliefs have the same set of interim-correlated-rationalizable outcomes. This solution concept characterizes common certainty of rationality in the...