Shortlisting of candidates—selecting a group of “best” candidates—is a special case of multiwinner elections. We provide the first in-depth study of the computational complexity of strategic voting for shortlisting based on the perhaps most basic voting rule in this scenario, \(\ell \)-Bloc (every voter approves \(\ell \) candidates). In particular, we investigate the influence of several different group evaluation functions (e.g., egalitarian versus utilitarian) and tie-breaking mechanisms modeling pessimistic and optimistic manipulators. Among other things, we conclude that in an egalitarian setting strategic voting may indeed be computationally intractable regardless of the tie-breaking rule. Altogether, we provide a fairly comprehensive picture of the computational complexity landscape of this scenario.

候选人入围——选择一组“最佳”候选人——是多赢选举的一个特例。我们基于这个场景中可能最基本的投票规则\(\ell \) -Bloc（每个选民都批准\(\ell \) 考生）。特别是，我们调查了几种不同的群体评估功能（例如，平等主义与功利主义）和模拟悲观和乐观操纵者的打破平局机制的影响。除其他外，我们得出的结论是，在平等主义的环境中，无论打破平局规则如何，战略投票在计算上确实是难以处理的。总而言之，我们提供了该场景计算复杂性格局的相当全面的图景。