Bribery in voting with soft constraints

Abstract We consider a multi-agent scenario where a collection of agents needs to select a common decision from a large set of decisions over which they express their preferences. This decision set has a combinatorial structure, that is, each decision is an element of the Cartesian product of the domains of some variables. Agents express their preferences over the decisions via soft constraints. We consider both sequential preference aggregation methods (they aggregate the preferences over one variable at a time) and one-step methods and we study the computational complexity of influencing them through bribery. We prove that bribery is NPcomplete for the sequential aggregation methods (based on Plurality, Approval, and Borda) for most of the cost schemes we defined, while it is polynomial for one-step Plurality

On the Hardness of Bribery Variants in Voting with CP-Nets

We continue previous work by Mattei et al. (Mattei, N., Pini, M., Rossi, F., Venable, K.: Bribery in voting with CP-nets. Ann. of Math. and Artif. Intell. pp. 1--26 (2013)) in which they study the computational complexity of bribery schemes when voters have conditional preferences that are modeled by CP-nets. For most of the cases they considered, they could show that the bribery problem is solvable in polynomial time. Some cases remained open---we solve two of them and extend the previous results to the case that voters are weighted. Moreover, we consider negative (weighted) bribery in CP-nets, when the briber is not allowed to pay voters to vote for his preferred candidate.Comment: improved readability; identified Cheapest Subsets to be the enumeration variant of K.th Largest Subset, so we renamed it to K-Smallest Subsets and point to the literatur; some more typos fixe

Bribery vs. Extortion: Allowing the Lesser of two Evils

Rewards to prevent supervisors from accepting bribes create incentives for extortion. This raises the question whether a supervisor who can engage in bribery and extortion can still be useful in providing incentives. By highlighting the role of team work in forging information, we present a notion of soft information that makes supervision valuable. We show that a fear of inducing extortion may make it optimal to allow bribery, but extortion is never tolerated. Even though both increase incentive cost, extortion penalizes the agent after “good behavior”, while bribery penalizes the agent after “bad behavior”. Since bribery occurs when a violation is detected, the bribe is a penalty for “bad behavior”, and helps somewhat in providing incentive. We find that extortion is a more serious issue when incentives are primarily based on soft information, when the agent has a greater bargaining power while negotiating an illegal payment, or when the agent has weaker outside opportunities. Our analysis provides explanations why extortion may be less of a problem in developed countries.monitoring, corruption, collusion, bribery, extortion, framing

07431 Abstracts Collection -- Computational Issues in Social Choice

From the 21st to the 26th of October 2007, the Dagstuhl Seminar 07431 on ``Computational Issues in Social Choice\u27\u27 was held at the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their recent research, and ongoing work and open problems were discussed. The abstracts of the talks given during the seminar are collected in this paper. The first section summarises the seminar topics and goals in general. Links to full papers are provided where available

The Recusal Alternative to Campaign Finance Legislation

Typical campaign finance proposals focus on limiting the amount of money that can be contributed to candidates and the amount of money that candidates can spend. This article suggests an alternative proposal that places no restrictions on contributions or spending, but rather targets the corrupting influence of contributions. Under the proposals, legislators would be required to recuse themselves from voting on issues directly affecting contributors. I contend that this proposal would prevent corruption and the appearance of corruption while remedying the first amendment objections to the regulation of money in campaigns