The trade-off between equity and efficiency is analyzed in a geometric framework for the problem of committee selection, which has recently attracted interest in the social choice literature. It is shown that this trade-off can be maximal in the precise sense of the antipodality of the outcomes...

An impossibility result for completely abstract social aggregation rules is presented. It is shown that non-imposition and a new no-veto property (two properties in the spirit of the Pareto principle and non-dictatorship respectively) are incompatible with an inter-profile consistency condition...

It is well known that the literature on judgement aggregation inherits the impossibility results from the aggregation of preferences that it generalises. This is due to the fact that the typical judgement aggregation problem induces an ultrafilter on the set of individuals. We propose a...