General, direct and self-implementation of social choice functions via protective equilibria (Q1068674)

This paper investigates the possibility of implementing social choice functions via protective equilibria - a refinement of maximin behavior. We describe a necessary condition, as well as a set of sufficient conditions for a social choice function to be implementable. The set of implementable functions is certainly not empty, and it contains interesting procedures, allowing for some agents to have some veto power. However, positional or Condorcet-type methods cannot be implemented via protective equilibrium. The connections and the differences between different notions of implementation are also discussed.