https://hal-hec.archives-ouvertes.fr/hal-00753237Gilboa, ItzhakItzhakGilboaNorthwestern University [Evanston]Schmeidler, DavidDavidSchmeidlerTel Aviv University [Tel Aviv]OSU - Ohio State University [Columbus]Maxmin Expected Utility with Non-Unique PriorHAL CCSD1989Non-Unique PriorMaxmin Expected Utility[SHS.ECO.ECO] Humanities and Social Sciences/Economics and Finance/Economy and decision scienceHaldemann, Antoine2012-11-18 20:17:302022-06-25 10:54:002012-11-18 20:17:30enJournal articles10.1016/0304-4068(89)90018-91Acts are functions from states of nature into finite-support distributions over a set of 'deterministic outcomes'. We characterize preference relations over acts which have a numerical representation by the functional J(f) = min > {∫ uo f dP / P∈C } where f is an act, u is a von Neumann-Morgenstern utility over outcomes, and C is a closed and convex set of finitely additive probability measures on the states of nature. In addition to the usual assumptions on the preference relation as transitivity, completeness, continuity and monotonicity, we assume uncertainty aversion and certainty-independence. The last condition is a new one and is a weakening of the classical independence axiom: It requires that an act f is preferred to an act g if and only if the mixture of f and any constant act h is preferred to the same mixture of g and h. If non-degeneracy of the preference relation is also assumed, the convex set of priors C is uniquely determined. Finally, a concept of independence in case of a non-unique prior is introduced.