17 October 2018, Computational Social Choice Seminar, Arthur Boixel
Social choice theory allows to study the way in which the aggregation of individual preferences can lead to the expression of a collective preference. It indirectly leads to ponder on the meaning we give to the idea of democracy. Unfortunately, social choice theory is stained with impossibility results, such as Arrow's Theorem, preventing the construction of simple and satisfactory preference aggregation methods. One way to escape the impossibility is to impose certain restrictions on the preferences that are used as voting input. In this presentation I will focus on the restriction to single-peaked preferences and we will see why this can be a usefull restriction. However, restricting the expression of indiviudal preferences is a non-democratic way for their aggregation: it forces us to violate the universality property which is desirable in democracy. Inspired by recent results obtained by List, Luskin, Fishkin, and McLean (The Journal of Politics, 2012) I will present the formalisation of a deliberation protocol that helps bringing the set of indiviudal preferences closer to such structure in a democratic way.
For more information on the Computational Social Choice Seminar, please consult https://staff.science.uva.nl/u.endriss/seminar/.