An observer makes a number of observations of an industry producing a homoge- neous good. Each observation consists of the market price, the output of individual firms and perhaps information on each firm's production cost. We provide vari- ous tests (typically, linear programs) with which the...

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)...

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 the comparative statics of Walrasian economies with excess demand functions which obey the weak axiom. We show that in these economies there is a precise sense in which goods that are in excess supply (demand) after some perturbation will experience a fall (rise) in its...

These are additional notes relating to the paper `The Comparative Statics of Constrained Optimization Problems' which is appearing in Econometrica. It gathers together material present in various earlier versions of the paper, as well as some new material, which are not found in the published...

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 agent's level of risk aversion when she is confronted with...

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 economys endowments are collinear, the excess demand function will obey the weak axiom when certain mild restrictions are imposed on...

We show that Grandmont's (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...