Judgement Aggregation and Multiwinner Elections

In most general terms, the theory of judgement aggregation (JA) investigates rules for making consistent collective judgements on a set of propositions on the basis of the group members' individual judgements on these propositions. A multiwinner election rule is a formal process for selecting a subset of candidates (not necessarily a sigleton!) based on the preferences of voters. A vast number of different scenarios can be embedded in the frameworks of multiwinner elections or JA, but apparently there have not been many attempts to apply JA to multiwinner elections. The purpose of the talk will be to introduce some basic results of the classical JA-theory, present a part of a research program within the framework of multiwinner election rules devoted to modelling fairness and proportionality of elections with the use of JA-tools and to present some examples motivating this part of the project.