摘要：Implementation in iteratively undominated strategies relies on permis-sive conditions. However, for the su.ciency results available, authors haverelied on assumptions that amount to quasilinear preferences on a numeraire.We uncover a new necessary condition that implies that such assumptionscannot be dispensed with. We term the condition "restricted deception-proofness." It requires that, in environments with identical preferences, thesocial choice function be immune to all deceptions, making it then strongerthan incentive compatibility. In some environments the conditions for (ex-act or approximate) implementation are more restrictive than previouslythought.
