Tribute to Jean-Yves Jaffray by the French Group of Decision Theory

We develop an axiomatic approach to decision under uncertainty that explicitly takes into account the information available to the decision maker. The information is described by a set of priors and a reference prior. We define a notion of imprecision for this informational setting and show that...

We provide a general theorem on the aggregation of preferences under uncertainty. We study, in the Anscombe-Aumann setting a wide class of preferences, that includes most known models of decision under uncertainty (and state-dependent versions of these models). We prove that aggregation is...

Ever since its introduction by Foley [1967] and Varian [1974], the notion of fairness has been one of the most extensively used notion to evaluate allocations on an ethical basis. Whereas there is an extensive literature on the efficiency properties of allocations in economies with uncertainty...

We show that, in a two-period economy with uncertainty in the second period, if an allocation is Pareto optimal for a given set of beliefs and remains optimal when these beliefs are changed, then the set of optimal allocations of the two economies must actually coincide. We identify equivalence...

We show that when decision makers are of the multiple prior kind, there is an equivalence between no betting and non empty intersection of the sets of priors.

This paper analyzes optimal wage contracting assuming agents are not subjective expectedutility maximizers but are, instead, ambiguity (or uncertainty) averse decision makers whomaximize Choquet expected utility. We show that such agents will choose not to include anyindexation coverage in their...

We analyze the aggregation problem without the assumption that individuals and society have fully determined and observable preferences. More precisely, we endow individuals ans society with sets of possible von Neumann-Morgenstern utility functions over lotteries. We generalize the classical...

This paper explores risk-sharing and equilibrium in a general equilibrium set-up wherein agents are non-additive expected utility maximizers. We show that when agents have the same convex capacity, the set of Pareto-optima is independent of it and identical to the set of optima of an economy in...

We report in this paper the result of three experiments on risk, ambiguity and time attitude. The first two differed by the population considered (students vs. general population) while the third one used a different protocol and concerned students and portfolio managers. We find quite a lot of...