This paper analyzes a model of decision under ambiguity, deemed vector expected utility or VEU. According to the proposed model, an act f :Ω→X is evaluated via the functional V ( f ) = ∫

Using a system of axioms, this paper develops a general utility model of other-regarding preferences when opponents are unfamiliar, but they are not strictly anonymous in the sense that they may share some history. Based on two key axioms, an individual’s preferences over a vector of probability distributions are additively separable in the decision maker’s own outcome and each opponent’s outco...

It is well known that ex post e¢ cient mechanisms for the provision of indivisible public goods are not interim individually rational. However, the corresponding literature assumes that agents who veto a mechanism can enforce a situation in which the public good is never provided. This paper instead considers majority voting with uniform cost sharing as the relevant status quo. E¢ cient mechani...

Techniques for the construction of dynamical Galaxy models should be considered essential infrastructure that should be put in place before GAIA flies. Three possible modelling techniques are discussed. Although one of these seems to have significantly more potential than the other two, at this stage work should be done on all three. A major effort is needed to decide how to make a model consis...

We characterize preferences over acts that can be represented by a utility function and a multiple–prior, such that an act f is preferred to act g if there is a prior under which the expected utility induced by f is higher than that induced by g. These preferences are referred to as justifiable preferences. We further introduce a generalized model of ambiguity that involves a collection of mult...

0.1. Preface. In 1963 Ya. G. Sinai [Sin(1963)] formulated a modern version of Boltzmann’s ergodic hypothesis, what we now call the “Boltzmann-Sinai Ergodic Hypothesis”: The billiard system of N (N ≥ 2) hard balls of unit mass moving on the flat torus T = R/Z (ν ≥ 2) is ergodic after we make the standard reductions by fixing the values of trivial invariant quantities. It took fifty years and the...