We show that the monotone continuity condition introduced by Villegas (1964) and Arrow (1970) is the behavioral counterpart of countable additivity (and relative weak compactness) in a multiple priors model. This generalizes their original result, in which the special case of a singleton set of...

We show, in the Choquet expected utility model, that preference for diversification, that is, convex preferences, is equivalent to a concave utility index and a convex capacity. We then introduce a weaker notion of diversification, namely "sure diversification." We show that this implies that...

In a two-period sunspot economy with inside money and "S" possible realizations of the sunspot, we prove that, generically in the space of utility functions, there are ["S" - 1] degrees of real indeterminacy. This result generalizes the previously known result for sunspot models that,...

This paper analyzes through a simple two-period model the fact that, if some agents hold inside money intertemporally, the second-period "normalization" matters. Thus, there are several equilibria of the second-period economy, indexed by the level of inflation. A concept of equilibrium...

This book surveys how economists engage with knowledge and beliefs in various fields of economic analysis, such as general equilibrium theory, decision theory, game theory, experimental economics, evolutionary theory of the firm, financial markets and the history of economic thought.

This paper assesses the quantitative impact of ambiguity on the historically observed financial asset returns and prices. The single agent, in a dynamic exchange economy, treats the conditional uncertainty about the consumption and dividends next period as ambiguous. We calibrate the agent's...

This chapter of a collective book aims at presenting the basics of decision making under risk. We first define notions of risk and increasing risk and recall definitions and classifications (that are valid independently of any representation) of behavior under risk. We then review the classical...

In this chapter, we adopt the decision theoretic approach to the representation and updating of beliefs. We take up this issue and propose a reconsideration of Hammond's argument. After reviewing the argument more formally, we propose a weaker notion of dynamic consistency. We observe that this...