The purpose of the paper is to introduce a tighter definition for the marginal pricing rule. By means of an example, we illustrate the improvements that one gets with the new definition with respect to the former one with the Clarke's normal come.

This paper considers an exchange economy with a measure space of agents and consumption externalities, which take into account two possible external effects on consumers’ preferences: dependence upon prices and dependence upon other agents’ consumption. We first consider a model with a...