We investigate the implications of relaxing Arrow's independence of irrelevant alternatives axiom while retaining transitivity and the Pareto condition. Even a small relaxation opens a floodgate of possibilities for nondictatorial and efficient social choice

Arrow's "impossibility" and similar classical theorems are usually proved for an unrestricted domain of preference profiles. Recent work extends Arrow's theorem to various restricted but "saturating" domains of privately oriented, continuous, (strictly) convex, and (strictly) monotone "economic...

Approval voting has attracted considerable interest among voting theorists, but they have rarely investigated it in the Arrovian frame-work of social welfare functions (SWF) and never connected it with Arrow's impossibility theorem. This note explores these two directions. Assuming that voters...

Judgment aggregation theory generalizes social choice theory by having the aggregation rule bear on judgments of all kinds instead of barely judgments of preference. The paper briefly sums it up, privileging the variant that formalizes judgment by a logical syntax. The theory derives from...

Arrow's theorem proves that no voting procedure can meet certain conditions of both fairness and logic. In this note, Grant Hayden explores the ramifications of the theorem for qualitative vote dilution. After describing Arrow's argument, Mr. Hayden considers four democratic voting procedures...

This chapter discusses different types of domain restrictions. We begin by analyzing various qualitative conditions on preference profiles. Value-restricted preferences (with single-peaked preferences as one of its subcases), limited agreement as well as antagonistic and dichotomous preferences...

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...

This article surveys the literature that investigates the consistency of Arrow's social choice axioms when his unrestricted domain assumptions are replaced by domain conditions that incorporate the restrictions on agendas and preferences encountered in economic environments. Both social welfare...

Any procedure of social choice makes use of some types of information and ignores others. For example, the method of majority decision concentrates on people's votes, but pays no direct attention to, say, their social standings, or their prosperity or penury, or even the intensities of their...