An abundant literature is concerned with the existence of equilibrium in incomplete markets where participation to financial markets is not restricted. To mention a few, Cass (1984), Werner (1985), Geanakoplos and Polemarchakis (1986), Duffie (1987), Duffie and Shafer (1985) and Magill and...

In this paper, we consider an incumbent firm facing potential entry in a vertical differentiation model a la Mussa and Rosen where consumers differ only by their intensity of preference for quality. We ask whether the incumbent firm has the incentive to adopt a multi-product strategy in order to...

In a pure exchange economy, we definie a new concept of local equilibria where the consumers are restricted by sale constraints. So the equilibrium consumptions are close to the initial endowments. We prove that the local equilibrium is always unique when utility functions are smooth and the...

We consider a general model of pure exchange economies with consumption externalities. Households may have different consumption sets and each consumption set is described by a function called possibility function. Utility and possibility functions depend on the consumptions of all households....