Junta distributions and the average-case complexity of manipulating elections
TLDR
It is shown that scoring protocols are susceptible to manipulation by coalitions, when the number of candidates is constant, and it is demonstrated that NP-hard manipulations may be tractable in the average-case.Abstract:
Encouraging voters to truthfully reveal their preferences in an election has long been an important issue. Recently, computational complexity has been suggested as a means of precluding strategic behavior. Previous studies have shown that some voting protocols are hard to manipulate, but used NP-hardness as the complexity measure. Such a worst-case analysis may be an insufficient guarantee of resistance to manipulation.
Indeed, we demonstrate that NP-hard manipulations may be tractable in the average-case. For this purpose, we augment the existing theory of average-case complexity with some new concepts. In particular, we consider elections distributed with respect to junta distributions, which concentrate on hard instances. We use our techniques to prove that scoring protocols are susceptible to manipulation by coalitions, when the number of candidates is constant.read more
Citations
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Handbook of Computational Social Choice
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References
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Journal ArticleDOI
An Introduction to Probability Theory and Its Applications
David A. Freedman,William Feller +1 more
Book
The Probabilistic Method
TL;DR: A particular set of problems - all dealing with “good” colorings of an underlying set of points relative to a given family of sets - is explored.
Journal ArticleDOI
Strategy-proofness and Arrow's conditions: Existence and correspondence theorems for voting procedures and social welfare functions
TL;DR: In this paper, the strategy-proofness condition for voting procedures corresponds to Arrow's rationality, independence of irrelevant alternatives, nonnegative response, and citizens' sovereignty conditions for social welfare functions.
Journal ArticleDOI
The computational difficulty of manipulating an election
TL;DR: A voting rule is exhibited that efficiently computes winners but is computationally resistant to strategic manipulation, showing how computational complexity might protect the integrity of social choice.