In this paper, we reconsider the full characterization of two-agent Nash
implementation provided in the celebrated papers byMoore and Repullo (Econometrica
58:1083–1099, 1990) and Dutta and Sen (Rev Econ Stud 58:121–128, 1991), since
we are able to show that the characterizing conditions are not logically independent.
We prove that an amended version of the conditions proposed in these papers is still
necessary and sufficient for Nash implementability. Then, by using our necessary and
sufficient condition, we show that Maskin’s impossibility result can be avoided under
restrictions on the outcomes and the domain of preferences much weaker than those
previously imposed by Moore and Repullo (Econometrica 58:1083–1099, 1990) and
Dutta and Sen (Rev Econ Stud 58:121–128, 1991).
