In social choice theory with ordinal preferences, a voting method satisfies the axiom of positive involvement if adding to a preference profile a voter who ranks an alternative uniquely first cannot cause that alternative to go from winning to losing. In this note, we prove a new impossibility theorem concerning this axiom: there is no ordinal voting method satisfying positive involvement that also satisfies the Condorcet winner and loser criteria, resolvability, and a common invariance property for Condorcet methods, namely that the choice of winners depends only on the ordering of majority margins by size.

翻译：在序数偏好的社会选择理论中，若在偏好分布中添加一位将某选项排为唯一首位的选民，不会导致该选项从胜选转为败选，则称该投票方法满足积极介入公理。本文证明了关于该公理的一个新不可能定理：不存在同时满足以下条件的序数投票方法——符合积极介入公理、孔多塞胜者与败者标准、可解性，以及孔多塞方法共有的不变性性质（即胜者选择仅取决于多数差额的规模排序）。