Complexity of Thiele voting on voter-interval profiles

Can an optimal size-k committee for a Thiele voting rule be found in polynomial time when each candidate’s approving voters form an interval in one voter order? The target also allows voter-specific scoring sequences.

Why it matters and what counts as progress

Why it matters: The restricted domain may make winner determination tractable even for rules difficult on general profiles.

What counts as progress: A polynomial-time algorithm for every stated Thiele rule on voter-interval profiles, or a hardness result within that same domain.

How the problem developed

  1. 2015 · Domain question [1]

    Edith Elkind and Jörg Lackner Introduced voter-interval preferences as a structured approval domain and posed polynomial-time Proportional Approval Voting as an open problem.

  2. 2018 · Generalized question [1]

    Dominik Peters Extended the open problem from Proportional Approval Voting to all Thiele rules on voter-interval profiles.

  3. 7 Apr 2026 · Algorithm [1]

    Pasin Manurangsi and Krzysztof Sornat Gave a polynomial-time algorithm for finding an optimal size-k committee under every Thiele rule on voter-interval approval profiles.

AI contribution

Sources

  1. Manurangsi and Sornat · Polynomial-time algorithm for Thiele voting rules with voter interval preferences (2026)
  2. Polynomial-Time Algorithm for Thiele Voting Rules with Voter Interval Preferences
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