We address the problem of choosing a portfolio of policies under "deep uncertainty." We introduce the idea of belief dominance as a way to derive a set of non-dominated portfolios and robust individual alternatives. Our approach departs from the tradition of providing a single recommended...

We review some of the (theoretical) economic implications of David Schmeidler's models of decision under uncertainty (Choquet expected utility and maxmin expected utility) in competitive market settings. We start with the portfolio inertia result of Dow and Werlang (1992), show how it does or...

Most decisions concerning (self-)insurance and self-protection have to be taken in situations in which a) the effort exerted precedes the moment uncertainty realises, and b) the probabilities of future states of the world are not perfectly known. By integrating these two characteristics in a...

The α-MEU model and the smooth ambiguity model are two popular models in decision making under ambiguity. However, the axiomatic foundations of these two models are not completely understood. We provide axiomatic foundations of these models in a symmetric setting with a product state space...

We investigate what it means for one act to be more ambiguous than another. The question is evidently analogous to asking what makes one prospect riskier than another, but beliefs are neither objective nor representable by a unique probability. Our starting point is an abstract class of...