一票，多个议会：对2022年意大利大选数据中选举法算法模糊性的实证分析
One Vote, Several Parliaments: An Empirical Analysis of the Algorithmic Ambiguity of the Italian Electoral Law on the 2022 General Election Data
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中文总结 AI 辅助
研究意大利选举法算法模糊性，通过实施席位分配流程并运行三种解释于2022年大选数据，发现顺序解释依赖顺序，实际应用解释与顺序无关，马塔雷拉式解释有席位无法分配，证实法定文本算法解释能改变当选人员和地点而非政党实力的观点。
中文摘要 AI 辅助
克拉法对意大利选举法（经第165/2017号法律修订的D.P.R. 361/1957，即罗萨泰利姆法）的算法分析表明，在各地区分配比例席位的法定文本（第83(1)(h)条）至少有三种算法解释，这些解释可以从相同选票中选出不同的人。我们对此进行了实证检验：实施完整的席位分配流程（第77、83、83 - 之二、84、85条），并对2022年9月25日意大利众议院大选的完整公开数据运行这三种解释。该实施从原始市政数据精确再现了官方全国分配情况，在其模拟的391个席位中，按姓名匹配了389个（99.5%），并与国家中央选举办公室的官方记录逐步一致；两个剩余不匹配情况落在众议院选举委员会在2025年进行正式调查的席位上。在这些经过验证的数据上，顺序解释（算法A）依赖于顺序：颠倒选区顺序会使6名议员被其他6名议员取代，1000个随机顺序产生560个不同结果；在29%的顺序中，算法A会留下一两个文本无法分配席位，在另外9%的顺序中会改变政党组成。实际应用的解释（算法C）与顺序无关，在无平局情况下可证明如此，但与算法A有8名议员的差异。马塔雷拉式解释（算法B）在每个顺序下都有两个席位无法分配。在实际记录的执行情况中法定补偿保留了每个政党的全国席位总数，蒙特卡罗分析表明，解释之间指定的差异对输入噪声具有很强的鲁棒性，远超数据的剩余不确定性：这种模糊性改变了当选人员和地点，而非政党实力。在真实数据上，这证实了克拉法的核心主张。
英文摘要
Crafa's algorithmic analysis of the Italian electoral law (the "Rosatellum") showed that the statutory text describing the territorial distribution of proportional seats (Art. 83(1)(h)) admits at least three different algorithmic interpretations, which may elect different people from the same votes. We test that conclusion empirically: we implement the full seat-allocation pipeline of the law (Arts. 77, 83, 83-bis, 84, 85) and run the three interpretations on the complete open data of the 2022 Italian general election (Chamber of Deputies). The implementation reproduces the official national apportionment exactly, matches by name 389 of the 391 seats it models (99.5%), and agrees step by step with the official minutes. On these validated data, the sequential interpretation (Algorithm A) is order-dependent: reversing the processing order of the constituencies replaces 6 deputies with 6 others, and 1,000 random orders produce 560 distinct outcomes; a near-exhaustive sweep of 15 million orders closes the set of order-contingent deputies at 140, while 764 of the 1,139 candidates of the admitted lists (67%) are elected under no order at all. In 29% of the sampled orders A also strands seats it cannot assign by any rule stated in the text, and in a further 9% it fills the Chamber with a different party composition. The interpretation applied in practice (Algorithm C) is order-independent, provably so in the absence of ties, but differs from A by 8 deputies. Under the Mattarella-style interpretation (Algorithm B) the documented order leaves two seats unassignable, and 46% of sampled orders strand one to three seats. A Monte Carlo analysis shows the named differences robust to input noise well beyond the residual uncertainty of the data: the ambiguity changes which persons are elected and in which territories, and leaves party strength untouched only where the text's procedure completes.
