Determining possible and necessary winners under common voting rules given partial orders
Usually a voting rule requires agents to give their preferences as linear orders. However, in some cases it is impractical for an agent to give a linear order over all the alternatives. It has been suggested to let agents submit partial orders instead. Then, given a voting rule, a profile of partial orders, and an alternative (candidate) c, two important questions arise: first, is it still possible for c to win, and second, is c guaranteed to win? These are the possible winner and necessary winner problems, respectively. Each of these two problems is further divided into two sub-problems: determining whether c is a unique winner (that is, c is the only winner), or determining whether c is a co-winner (that is, c is in the set of winners). We consider the setting where the number of alternatives is unbounded and the votes are unweighted. We completely characterize the complexity of possible/necessary winner problems for the following common voting rules: a class of positional scoring rules (including Borda), Copeland, maximin, Bucklin, ranked pairs, voting trees, and plurality with runoff. © 2011 AI Access Foundation. All rights reserved.
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- Artificial Intelligence & Image Processing
- 4611 Machine learning
- 4603 Computer vision and multimedia computation
- 4602 Artificial intelligence
- 1702 Cognitive Sciences
- 0801 Artificial Intelligence and Image Processing
- 0102 Applied Mathematics
Citation
Published In
DOI
EISSN
Publication Date
Volume
Start / End Page
Related Subject Headings
- Artificial Intelligence & Image Processing
- 4611 Machine learning
- 4603 Computer vision and multimedia computation
- 4602 Artificial intelligence
- 1702 Cognitive Sciences
- 0801 Artificial Intelligence and Image Processing
- 0102 Applied Mathematics