Preferences Single-Peaked on a Tree: Multiwinner Elections and Structural Results

  title={Preferences Single-Peaked on a Tree: Multiwinner Elections and Structural Results},
  author={Dominik Peters and Lan Yu and Hau Chan and Edith Elkind},
  journal={J. Artif. Intell. Res.},
A preference profile is single-peaked on a tree if the candidate set can be equipped with a tree structure so that the preferences of each voter are decreasing from their top candidate along all paths in the tree. This notion was introduced by Demange (1982), and subsequently Trick (1989b) described an efficient algorithm for deciding if a given profile is single-peaked on a tree. We study the complexity of multiwinner elections under several variants of the Chamberlin–Courant rule for… 

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