In this paper, we develop a differentiable approach to deal with incentives
in a, possibly small, subset of a general domain of preferences in economies with one
public and one private good.We showthat, for two agents, there is no mechanism which
is efficieIn this paper, we develop a differentiable approach to deal with incentives
in a, possibly small, subset of a general domain of preferences in economies with one
public and one private good.We showthat, for two agents, there is no mechanism which
is efficient, strategy-proof and where consumption of both goods is positive for all
agents. For the case of two or more agents the same result occurs when nondictatorship
is replaced by Individual Rationality.[+][-]