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.

A single condition, limited arbitrage, is shown to be necessary and sufficient for the existence of a competitive equilibrium and the core in economies with any number of markets, finite or infinite, with or without short sales. This extends earlier results of Chichilnisky [8] for finite...

Sont presentees ici quelques reflexions portant sur la dynamique de la mondialisation, de la competition, du reseautage et du processus decisionnel collectif.

Consider a two period financial economy with incomplete markets and with agents having von Neumann-Morgenstern utility functions. It is well known that when the economy’s endowments are collinear, its excess demand function will obey the weak axiom when certain mild restrictions are...

The main purpose of this paper is to remark that any definable continuous path linking two regular equilibria in a regular O-minimal equilibrium manifold intersects a finite number of definable connected components locally determined. We apply the cell decomposition theorem to decompose the...

The main purpose of this paper is to outline that the definable Debreu map is a local definable diffeomorphism. It implies the equilibrium is locally determined in each connected component partitioning a regular O-minimal equilibrium manifold. It complements the result in Theorem 5 of Arias-R....

In this paper we introduce basic notions of new economic model where preference relations on commodities set are represented by a group action on Euclidean space instead of utility function. Conditions that ensure the existence of individual demand functions and a general equilibrium in the...

In this paper we provide necessary and sufficient conditions for the excess demand function of a pure exchange economy to be globally invertible so that there is a unique equilibrium. Indeed, we show that an excess demand function is globally invertible if and only if its Jacobian never vanishes...

The aim of this paper is to prove that if the consumption set of an economy with incomplete financial markets is semi-algebraic, then the corresponding pseudo-equilibrium manifold is also semi-algebraic. For this, we proceed by constructing an incomplete financial economy with real assets and...