Measuring self-selectivity via generalized Condorcet rules

Abstract

In this thesis, we introduce a method to measure self-selectivity of social choice functions. Due to Koray [2000], a neutral and unanimous social choice function is known to be universally self-selective if and only if it is dictatorial. Therefore, in this study, we confine our set of test social choice functions to particular singleton-valued refinements of generalized Condorcet rules. We show that there are some non-dictatorial self-selective social choice functions. Moreover, we define the notion of self-selectivity degree which enables us to compare social choice functions according to the strength of their selfselectivities. We conclude that the family of generalized Condorcet functions is an appropriate set of test social choice functions when we localize the notion of self-selectivity.