A decision-maker is said to have an ambiguous belief if it is not precise enough to be represented by a single probability distribution. The pervasive assumption in game theoretic models in economics is that players' beliefs are unambiguous. This paper argues, drawing on examples from economics...

In 1989, I. Gilboa and D. Schmeidler proposed an extension of subjective expected utility theory called maxmin expected utility. The author presents a new exposition of this theory and suggests an extension of maxmin expected utility that which does not allow strictly dominated alternatives to...

In this paper, the authors propose a method for comparing risk aversion within the state-dependent utility model. This model is useful for analyzing economic problems relating to health or life. The authors extend the Arrow-Pratt measure of risk aversion to the case where utility is...

This paper criticizes the claim that the Arrow Impossibility Theorem arises from an attempt to make social welfare judgments based on inadequate information. This paper shows how it is possible to modify conventio nal social choice to include those kinds of information the absence o f which is...

This paper gives a simple account of nonlinear dynamics, focusing on cycles and chaos. There is a survey of economic models that involve chaos. The case where a chaotic system is subject to exogenous random shocks is discussed. Copyright 1988 by Royal Economic Society.