I consider the problem of the design of an optimal self-selecting contract scheme for a principal who is buying a good from an agent which has the opportunity of making a cost-reducing unobservable investment prior to the contracting stage. Because of a hold-up problem, the agent will randomizes...

In this paper, I consider the problem of designing an optimal screening contract for a principal facing an agent whose type comes as a sequence that unfolds through time. Formally, the agent has a private ex ante type that stands for the expected value of his private ex post type. Under full...

In spatial environments we consider social welfare functions satisfying Arrow’s requirements, i.e. weak Pareto and independence of irrelevant alternatives. Individual preferences measure distances between alternatives according to the Lp-norm (for a fixed p = 1). When the policy space is...

Although the theory of greatest-element rationalizability and maximal-element rationalizability under general domains and without full transitivity of rationalizing relations is well-developed in the literature, these standard notions of rational choice are often considered to be too demanding....

We study the implications of two solidarity conditions on the efficient location of a public good on a cycle, when agents have single-peaked, symmetric preferences. Both conditions require that when circumstances change, the agents not responsible for the change should all be affected in the...

We examine properties of binary relations that complement quasi-transitivity and Suzumura consistency in the sense that they, together with the original axiom(s), are equivalent to transitivity. In general, the conjunction of quasi-transitivity and Suzumura consistency is strictly weaker than...

We study the problem of defining inequality-averse social orderings over the space of allocations in a multi-commodity environment where individuals differ only in their preferences. We formulate notions of egalitarianism based on the axiom that any dominance between the consumption bundles of...

We reconsider the problem of aggregating individual preference orderings into a single social ordering when alternatives are lotteries and individual preferences are of the von Neumann-Morgenstern type. Relative egalitarianism ranks alternatives by applying the leximin ordering to the...

In a seminal contribution, Hansson has demonstrated that the family of decisive coalitions associated with an Arrovian social welfare function forms an ultrafilter. If the population under consideration is infinite, his result implies the existence of nondictatorial social welfare functions. He...

We characterize a class of collective choice rules such that collective preference relations are consistent. Consistency is a weakening of transitivity and a strengthening of acyclicity requiring that there be no cycles with at least one strict preference. The properties used in our...