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

This chapiter of a collective book is dedicated to classical decision models under uncertainty, i.e. under situations where events do not have "objective" probabilities with which the Decision Marker agrees. We present successively the two main theories, their axiomatic, the interpretation and...

This chapter of a collective book aims at presenting cardinal extensions of the EU model, based on the Choquet integral, which allow to take into account observed behaviors as in Allais' paradox under risk or Ellsberg's paradox under uncertainty, where the expected utility model is violated....

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 studies monotone risk aversion, the aversion to monotone, meanpreserving increase in risk (Quiggin [21]), in the Rank Dependent Expected Utility (RDEU) model. This model replaces expected utility by another functional, characterized by twofunctions, a utility function u in conjunction...

We reconsider the principles of diminishing transfer (introduced by Kolm [1976]) and dual diminishing transfer (introduced by Mehran [1976]). It appears that if a Rank Dependent Expected Utility (RDEU) maximizer respects the principle of diminishing (resp. dual diminishing) transfer, then he...

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...

The aim of this paper is two-fold : first, to emphasize that the seminal result of Dow and Werlang [9] remains valid under weaker conditions and this even if non-positive prices are considered, or equally that the no-trade interval result is robust when considering assets which can yield...

We show that the monotone continuity condition introduced by Arrow (1970) is the behavioral counterpart of countable additivity and weak compactness of the set of priors in a maxmin expected utility model. This generalizes Arrow's original result, who considered the special case of a singleton...

This paper presents a characterization of weak risk aversion in terms of preference for sure diversification. Similarly, we show that strong risk aversion can be characterized by weakening preference for diversification, as introduced by Dekel [11], in what we name preference for strong...