A social choice hyperfunction picks a non-empty set of alternatives at each admissible preference profile over sets of alternatives. We analyze the manipulability of social choice hyperfunctions. We identify a domain D of lexicographic orderings which exhibits an impossibility of the Gibbard-Satterthwaite type. Moreover, this impossibility is inherited by all well-known superdomains of D. As mo...

Given a society confronting a set of alternatives A, we consider the aggregation of individual preferences over the power set A of A into a social preference over A. In case we allow individuals to have any complete and transitive preference over A, Arrow’s impossibility theorem naturally applies. However, the Arrovian impossibility prevails, even when the set of admissible preferences over A i...