标题： 澳大利亚投票：可转移投票，其局限性和优势 显示英文标题

标题： The Australian Vote: Transferable Voting, Its Limitations and Strengths

摘要： 已知的投票系统称为替代投票（AV）和单一可转移投票（STV），在澳大利亚的选举中被广泛使用，可能比其他任何司法管辖区都更广泛。 通常被提出作为多数制和其他常见系统的优越替代方案，它们也因对悖论性结果的脆弱性而受到理论家的批评。 认为这些“可转移投票”系统实际上旨在平衡试图提炼“多数规则”和“选民选择”共同概念的竞争性要求。 AV 的一个积极特性是其结果总是两个具有大量选民支持的候选人的多数决，且获得至少三分之一选票的康多塞赢家总是会被选上。 显示在没有选出康多塞赢家的情况下，总存在一个单调变化产生康多塞循环而不改变选举结果。 提供了对三方竞争中非单调性悖论的详细分析，借助一个二维空间模型，其中每个候选人都有四分之一的概率获得绝对多数的初选票，同时也有类似的四分之一概率没有任何候选人赢得多数。 在这种模型下，显示非单调性存在于少于3.5%的选举情景中（并推测少于3%），并且更详细地研究了非单调性与康多塞循环和不稳定性的密切联系。 还回顾了多赢 STV 的特性，包括演示了一个标准事实，即在选票严格按政党忠诚度投出的特殊情况下，STV 会类似于一种最大余数名单投票形式。 通过参考澳大利亚选举的实践，提出了 AV 和 STV 体现了选民选择的原则，同时平衡了绝对和相对的多数规则概念。 显示英文摘要

摘要： The voting systems known as Alternative Vote (AV) and Single Transferable Vote (STV) are extensively used for elections in Australia, possibly more than in any other jurisdiction. Often proposed as superior alternatives to Plurality and other common systems, they are also criticised by theoreticians for their vulnerability to paradoxical outcomes. It is argued these 'transferable voting' systems in fact operate to balance competing desiderata that attempt to distil the common notions of 'majority rule' and 'voter choice'. Among positive characteristics of AV is that its outcome is always a majority runoff between two candidates with substantial voter support, and that a Condorcet winner who gains at least one-third of votes is always elected. It is shown that in situations where a Condorcet winner is not elected, there always exists a monotonic shift producing a Condorcet cycle without changing the election outcome. A detailed analysis of non-monotonicity paradoxes in three-way contests is provided, aided by a two-dimensional spatial model where each candidate has a one-in-four probability of gaining an absolute majority of primary votes while there is a similar one-in-four probability that no candidate wins a majority. On such a model it is shown non-monotonicities are latent in less than 3.5% of election scenarios (and conjectured to be less than 3%), and the close link between non-monotonicities and Condorcet cycles and instabilities is studied in more detail. Properties of multi-winner STV are also reviewed including a demonstration of the standard fact that STV becomes similar to a form of largest-remainder list voting in the special case where ballots are cast strictly by party allegiance. The argument that AV and STV exemplify the principle of voter choice while balancing absolute and relative concepts of majority-rule is made by reference to practice in Australian elections.