Manipulation of voting schemes with restricted beliefs

In this paper we define manipulation with restricted beliefs as the possibility for some voter to have an insincere preference ordering that dominates the sincere one within the given individual beliefs over other agents’ preferences. We then show that all non-dictatorial voting schemes are manipulable in this sense, up to a given threshold.     

Violations of Independence under Amendment and Plurality Rules with Anonymous Voters

Under the impartial anonymous culture assumption (IAC), we evaluate the proportion of anonymous profiles at which the amendment and plurality voting procedures violate the property of independence of irrelevant alternatives (IIA). We also examine the relation to single-peakedness of preferences and election of a Condorcet winner.      

Pareto violations of parliamentary voting systems

It has been known for a long time that many binary voting rules can select a Pareto dominated outcome, that is an outcome such that there exists some other alternative which is preferred by every voter. In this paper, we show that some of these rules can select an outcome Pareto dominated in a much stronger sense. Furthermore, our main results are concerned with the evaluation of the likelihood of Pareto dominated outcomes under four social choice rules commonly used in Parliaments or in committees. Given a set of four alternatives and a set of n individuals, we assume anonymous profiles and using analytical methods we compute the proportion of profiles at which the Pareto criterion is violated. Our results show that one should not be especially worried about the existence of the possibility as such. We are grateful to two anonymous referees for very helpful remarks and suggestions.