In this paper we investigate the problem of selecting a committee consisting of k members from a list of m candidates. Each candidate has a certain cost or weight. The choice of the k-committee has to satisfy some budget or weight constraint: the sum of the weights of all committee members must...

We show how ultrafilters can be used to prove a central impossibility result in judgement aggregation introduced by Nehring and Puppe (2005), namely that for a logically strongly interconnected agenda, an independent and monotonic judgement aggregation rule which satisfies universal domain,...

This paper is concerned with the manipulability of common voting rules, in particular with the Borda rule and other scoring rules. It is shown that, if one deviates from the assumption of complete information of the voters about the preference profile in the slightest possible manner, the Borda...