The overlapping expectations and the collective absence of arbitrage conditions introduced in the economic literature to insure existence of Pareto optima and equilibria when short-selling is allowed and investors hold a single belief about future returns, is reconsidered. Investors use measures...

This article reconsiders the theory of existence of efficient allocations and equilibria when consumption sets are unbounded below under the assumption that agents have incomplete preferences. It is motivated by an example in the theory of assets with short-selling where there is risk and...

We consider a pure exchange overlapping generations economy with finitely many commodities and consumers per period having possibly non-complete non transitive preferences. We provide a geometric and direct proof of the Balasko-Shell characterization of Pareto optimal allocation. To avoid some...

We consider a standard pure exchange overlapping generations economy. The demographic structure consists of a new cohort of agents at each period with an economic activity extended over two successive periods. Our model incorporates durable goods that may be stored from one period to a...

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....

Static competitive equilibria in economies with incomplete markets are generically constrained suboptimal. Allocations induced by strategic equilibria of imperfectly competitive markets are also generically inefficient. In both cases, there is scope for Pareto-improving amendments. In an...

In the spirit of Smale's work, we consider pure exchange economies with general consumption sets. In this paper, the consumption set of each household is described in terms of a function called possibility function. The main innovation comes from the dependency of each possibility function with...

The theory of existence of equilibrium with short-selling is reconsidered under risk and ambiguity modelled by risk averse variational preferences. A sufficient condition for existence of efficient allocations is that the relative interiors of the risk adjusted sets of expectations overlap. This...

We establish that an exchange economy, i.e., preferences and endowments, that generates a giiven aggregate excess demand (AED) function is close to the economy generating the AED obtained by an arbitrary perturbation of the original one.