Natural implementation with partially hones agents

The paper proposes necessary and sufficient conditions for the natural implementation of(efficient) social choice correspondences (SCCs) in pure finite exchange economies when some ofthe agents are partially honest. A partially honest agent is an agent who strictly prefers to tellthe truth when lying has no better material consequences for her. Firstly, it is shown that ifthere is even one partially honest agent in the economy (and the planner does not know heridentity), then any SCC is Nash implementable by a natural price-allocation mechanism. Secondly,and in sharp contrast with the results of conventional models of natural implementation, it isshown that the equivalence relationship between natural price-allocation mechanisms and naturalprice-quantity² mechanisms no longer holds. Finally, and even more strikingly, the paper reportsthat the class of implementable SCCs by natural price-quantity mechanisms is significantly enlarged.