Voting operators map n-tuples of subsets of a given set X of candidates (the voters’ choices) into subsets of X (the social choice). This paper characterizes dictatorial voting operators by means of three conditions (the non-emptiness condition A1, the independence condition A2 and the...

We consider the problem of implementing a social choice correspondence H in Nash equilibrium when the constitution of the society is given by an effectivity function E. It is assumed that the effectivity function of $ H,E^{H}$, is a sub-correspondence of E. We found necessary and efficient...