This paper gives a proof of the existence of competitive equilibrium under the added assumption that the excess demand function satisfies the weak axiom. In this case, a proof using the separating hyperplane theorem, and without using a fixed point theorem, is possible.

We examine the impact of the normality assumption, together with the weak axiom, in three related areas of general equilibrium theory. Most obviously, these properties have important implications for equilibrium comparative statics, in the context of exchange, production or (incomplete)...

This paper gives a unified and simple treatment of three related questions in the demand theory of the weak axiom: (i) Is there an elementary, i.e., non-fixed point theoretic, proof of equilibrium existence when the excess demand function of an economy satisfies the weak axiom? (ii) What...

We show that Grandmonts (1992) model of demand heterogeneity can be a model of heterogeneity in the complementary or sign-balancing sense. By this we mean that heterogeneity has the following form: given a change in price, agents respond heterogenously - some by increasing their expenditure...

This note proposes a necessary and sufficient condition on a preference to guarantee that the demand function it generates satisfies the law of demand. It shows that the law of demand may be succinctly characterized by differences in an agents level of risk aversion when she is confronted with...

This note determines the precise connection between an agent`s attitude towards income risks and his attitude over risks in the underlying consumption space. Our results follow a general mathematical theory connecting the curvature properties of an objective function with the ray-curvature...

A common theme in the theory of demand aggregation is that market demand can acquire properties which are not always individually present among the agents who make up that market, a phenomenon we call heterosis in this paper. This paper focusses on the well known result that with a suitable...

This paper examines conditions which guarantee that the excess demand function of an exchange economy will satisfy the weak axiom in an open neighborhood of a given equilibrium price. This property ensures that the equilibrium is locally stable with respect to Walras tatonnement. A related issue...