Interest, profit and saving in Arrow-Debreu equilibrium models

The paper aims to point out that the concepts of interest, profit and saving that we come across in the Arrow-Debreu equilibrium models are significantly different from what is usually indicated by these same terms in economic analysis. In fact, in the Arrow-Debreu models, they are not related to the investment of capital. As we shall try to show, the difficulties that the Arrow-Debreu theory encounters with reference to capital and related concepts derive from the hypothesis of markets open in a single moment that characterizes these models.