On the manipulability of equitable voting rules
研究在两选项投票中公平性与可操纵性之间的权衡，发现温和条件下，两两公平的投票规则中匿名性与多种群体防策略性等价，表明匿名性在公平性和不可操纵性上具有特殊性。
We consider the equity-manipulability trade-off when voting over two alternatives. Pairwise equity is a weakening of anonymity requiring certain permutations of the voters' identities to preserve the outcome of the election. ℓ-robust group strategy-proofness (ℓ-RGSP) and fine robust group strategy-proofness (FRGSP) are notions of group strategy-proofness that allow voters to have different beliefs about players' types (Kivinen and Tumennasan, 2021). Our main results show that, under mild conditions, for pairwise equitable voting rules anonymity is equivalent to 2-RGSP, 3-RGSP, and FRGSP. In this way, anonymity is special in its equity and non-manipulability. These results follow from several preliminary results, one of which equates 2-RGSP to comonotonicity and swap-robustness. Finally, we consider the manipulability of k-unanimous rules, and 2-RGSP when agents can be indifferent and abstain.