Econ Papers Daily / 期刊论文
一致性与社会选择：可能与不可能
Consistency and social choice: Possibilities and impossibilities
摘要
We study different notions of consistency in a model of preference aggregation where the feasible set of alternatives may vary. We show that there exists no social choice function (SCF) satisfying contraction consistency (CC), non-dictatorship, and Pareto efficiency (PE). We then characterize a class of priority-based SCFs, called Priority Rules (PRs), in two ways: first, using PE and efficient dominance, a WARP-type consistency condition with respect to PE; and second, using PE, weak contraction consistency, and invariant efficiency. We also characterize Decisive Individual Rules, in which the decisive individual may vary across profiles, using a top-selection condition, a weakening of CC, and an intersection condition on decisive individuals. Finally, in the social choice correspondence (SCC) setting, when the number of alternatives exceeds the number of voters, we characterize Voting by Minimal Committees SCCs using correspondence contraction consistency, top selection, unanimity, and committee intersection.
中文摘要
我们研究在一个可行备选集合可能变化的偏好聚合模型中，不同的一致性概念。我们表明，不存在满足收缩一致性（CC）、非独裁性和帕累托效率（PE）的社会选择函数（SCF）。随后，我们以两种方式刻画了一类基于优先权的SCF，称为优先规则（PRs）：第一，使用PE和有效支配，即一种关于PE的WARP型一致性条件；第二，使用PE、弱收缩一致性和不变效率。我们还刻画了决定性个人规则，其中决定性个人可能因偏好剖面而异，使用的是顶部选择条件、CC的一种弱化，以及关于决定性个人的交集条件。最后，在社会选择对应（SCC）框架中，当备选方案数量超过选民数量时，我们使用对应收缩一致性、顶部选择、一致同意和委员会交集来刻画最小委员会投票SCC。