Title of the lecture
“An introduction to the theory of single-winner elections”
Various organizations (states, municipalities, private companies, university faculties, etc.) resort to a wide variety of voting rules to achieve a seemingly same outcome, viz. electing a candidate (or, as the case may be, a policy alternative) that best reflects the will of the voters. We show by way of a few examples that the voting rule can be an equally important determinant of the outcome as the opinions of the voters. We then introduce some properties of voting rules that are generally deemed desirable. Thereafter we discuss some well-known results in social choice theory demonstrating the incompatibility of some of these desiderata. Our specific focus is on monotonicity-related properties which basically state that adding the electoral support, ceteris paribus, should do no harm for the candidate or policy alternative. Finally we touch upon a relatively recent electoral reform proposal insprired by social choice considerations.