We characterize, in the Anscombe-Aumann framework, the preferences for which there are a utility functionu on outcomes and an ambiguity indexc on the set of probabilities on the states of the world such that, for all acts f and g, Copyright The Econometric Society 2006.

We provide a simple behavioral definition of 'subjective mixture' of acts for a large class of (not necessarily expected-utility) preferences. Subjective mixtures enjoy the same algebraic properties as the 'objective mixtures' used to great advantage in the decision setting introduced by...

A decision maker (DM) is characterized by two binary relations. The first reflects choices that are rational in an "objective" sense: the DM can convince others that she is right in making them. The second relation models choices that are rational in a "subjective" sense: the DM cannot be...

We propose and characterize a model of preferences over acts such that the decision maker prefers act f to act g if and only if <openface>E</openface>_μφ( <openface>E</openface>_πu&cir;f) &ges; <openface>E</openface>_μφ( <openface>E</openface>_πu&cir;g), where <openface>E</openface> is the expectation operator, u is a von Neumann-Morgenstern utility function, φis an increasing transformation, and μis a...

This paper provides an axiomatic foundation for decision making in complex settings in which the decision maker does not have complete structural knowledge of the environment. The agent knows the set of actions he can take, he formulates preferences directly on the actions, and chooses according...

In this paper we study the indeterminacy of equilibria in infinite horizon capital accumulation models with technological externalities. Our investigation encompasses both models with bounded and unbounded accumulation paths, and models with one and two sectors of production. Under reasonable...