We consider a model with an finite number of states of nature where short sells are allowed.

We consider a model with an inffnite number of states of nature, von Neumann - Morgenstern utilities, where agents have different probabil- ity beliefs and where short sells are allowed. We show that no-arbitrage conditions, deffned for ffnite dimensional asset markets models, are not sufficient...

We address in this paper the question of the existence of a Social Welfare Function that would be sustainable and would allow us to obtain solutions to optimal growth models. We define sustainability by two new axioms called Never-decisiveness of the present and Never-decisiveness of the future....

Dans ce papier, nous reconsidérons les conditions de non-arbitrage collectif de la littérature économique qui assurent l'existence des optima de Pareto et des équilibres quand on permet les ventes à découvert et quand les agents ont une seule croyance sur les états de la nature. Les...