任何人但 him：排除替代品的复杂性
Anyone but Him: The Complexity of Precluding an Alternative
AI总结：
本文研究了在多智能体环境下，通过机制如选民/候选人添加/删除/分割等，防止特定候选人获胜的复杂性问题，发现不同选举系统对破坏性控制的防护能力各不相同。
摘要：
在多智能体环境中，偏好聚合是一个在人类和计算机领域都至关重要的问题。在本文中，我们从复杂性角度研究偏好聚合对破坏性控制的脆弱性。也就是说，我们研究选举主席通过诸如选民/候选人添加/删除/分割等机制，确保特定候选人（等价于替代品）不获胜的能力。我们还研究选举系统在多大程度上可以使其不可能，或使主席执行此类控制变得计算上昂贵（NP完全）。在我们研究的系统中——多数制、Condorcet制和审批制——我们发现了一些系统即使免疫或对主席选择获胜者具有计算抵抗力，仍可能受到主席阻止胜利的威胁。此外，我们发现，在我们研究的系统中，没有任何一个系统能提供对破坏性控制的最佳保护。相反，选择偏好聚合系统将取决于希望保护 against 的控制类型。我们还发现，基于自然平局处理规则的选择，控制的复杂性或易受控制的程度会显著变化。
英文摘要：
Preference aggregation in a multiagent setting is a central issue in both human and computer contexts. In this paper, we study in terms of complexity the vulnerability of preference aggregation to destructive control. That is, we study the ability of an election's chair to, through such mechanisms as voter/candidate addition/suppression/partition, ensure that a particular candidate (equivalently, alternative) does not win. And we study the extent to which election systems can make it impossible, or computationally costly (NP-complete), for the chair to execute such control. Among the systems we study--plurality, Condorcet, and approval voting--we find cases where systems immune or computationally resistant to a chair choosing the winner nonetheless are vulnerable to the chair blocking a victory. Beyond that, we see that among our studied systems no one system offers the best protection against destructive control. Rather, the choice of a preference aggregation system will depend closely on which types of control one wishes to be protected against. We also find concrete cases where the complexity of or susceptibility to control varies dramatically based on the choice among natural tie-handling rules.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
