Over the years, mathematics and statistics have become increasingly important in the social sciences. A look at the history quickly confirms this claim. At the beginning of the 20 century most theories in the social sciences were formulated in qualitative terms while quantitative methods did not play a substantial role in the formulation and establishment of them. Moreover, many practitioners c...

Let V be a society whose members express weak preferences about two alternatives. We show simple representation formulae that are valid for all, and only, the elements of various classes non-manipulable social choice functions on V. represent entire class functions, its subclasses corresponding to further properties. focus mainly anonymity. Efficiency neutrality up one voter also considered. As...