Thesis Defense Clinton Gubong Gassi (November, 8)

Clinton Gubong Gassi will present his doctoral dissertation entitled : "Multiple approaches to analysing the selection of a committee"

Supervisors : Mostapha Diss & Issofa Moyouwou

Date and place : November 8, 2 pm / UFR SJEPG, salle des actes, 45D avenue de l'observatoire, Besançon

Abstract: This thesis falls within the framework of social choice theory and focuses specifically on voting situations where the goal is to select a group of alternatives or candidates from a larger set, based on the preferences of a group of voters. This type of voting situation is known in social choice theory as ‘‘committee selection’’. In the first chapter of the thesis, we focus the basic case where the goal is to select a single alternative. In this chapter, we highlight the undeniable link between two well-known concepts in social choice theory, namely the majoritarian compromise rule and the notion of social acceptability. In the second chapter, we explore the more general framework of selecting a committee of any size, greater than 1. We address this issue by incorporating a crucial parameter in this context: the diversity constraint. We then propose a family of committee selection rules with a diversity constraint and study the properties of these rules. In the third chapter, we analyze the loss of excellence induced by the diversity constraint on the selected committee and examine how this varies from one rule to another, allowing for a qualitative comparison between different voting rules. Finally, in the fourth and last chapter, we address the issue of selecting a committee by incorporating another criterion, that of the compatibility of the selected committee members. We then propose a method to integrate the compatibility criterion into any classical scoring rule, in order to achieve a compromise between excellence and compatibility.