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，若在偏好剖面上增加一位将某一备选方案排为唯一首位的投票者，不会导致该方案从胜选变为落选，则称该投票方法满足积极介入公理。本文证明了一个关于该公理的新不可能定理：不存在同时满足孔多塞胜者准则、孔多塞败者准则、可解性以及孔多塞方法共同的不变性条件（即胜选方案选择仅取决于多数差额的规模排序）的序数投票方法。