Fuzzy set theory has been explicitly introduced to deal with vagueness and ambiguity. One can also use probability theory or techniques borrowed from philosophical logic. In this chapter, we consider fuzzy preferences and we survey the literature on aggregation of fuzzy preferences. We restrict...

We study the problem of locating a single public good along a segment when agents have single-dipped preferences. We ask whether there are unanimous and strategy-proof rules for this model. The answer is positive and we characterize all such rules. We generalize our model to allow the set of...

A new class of preference-aggregation rules is proposed, weak-veto rules. Weak-veto rules are applicable in settings characterized by strong pre-existing views on the desirability of different outcomes, whose recommendations should be modified only in the presence of strenuous opposition. They...

In this paper we present some results for preference aggregation functionals defined on rich admissible sets. Our results are concerned with an Independence of Irrelevant Alternatives assumption due to Alan D. Taylor suitably adjusted to be applicable in the framework of preference aggregation...

In this paper we are concerned with the following question. Given an extended preference ordering under what conditions does there exist an empirical stochastic/social choice function which generates it? We use Farkas' lemma to obtain a necessary and sufficient condition under which such a...

This paper is concerned with preference-aggregation rules satisfying desirable efficiency and solidarity requirements. We formulate weaker versions of existing solidarity axioms and show how they imply, in conjunction with strategy-proofness, the existence of reference outcomes holding...

This paper introduces excluding outlier voters (EOV) as a general mechanism for revealing true preferences in social choices, and for discouraging voters from strategic voting and manipula-tion. This mechanism is general in that it can be implemented with any voting system. The paper...

Politicians, CEOs and various other types of dictators make social choices that influence both their own and others' welfare. When a dictator's preferred alternative differs from recipients', it is unclear which preferences they aggregate and how they determine this set of admissible...

Consider a setting in which individual strict preferences need to be aggregated into a social strict preference relation. For two alternatives and an odd number of agents, it follows from May’s Theorem that the majority aggregation rule is the only one satisfying anonymity, neutrality, and...

When preferences are single-peaked (Black (1948),Black et al. (1958)) or group separable Ballester and Haeringer (2011), majority voting equilibria exist. Group separability has probably not received as much attention as single-peak separability because there are no intuitive assumptions about...