In many economic contexts, a given function can be disaggregated as a linear combination of gradients. Examples include the literature on the characterization of aggregate demand and excess demand, as initiated by Sonnenschein (1973ab), and the model of efficient household behaviour recently...

Mixture sets were introduced by Herstein and Milnor (1953) into decision theory, where they are still widely used. This note clarifies the formal connection between mixture sets and convex sets. The results suggest that the former concept might be unnecessary for decision- theoretic purposes.

This paper puts forth a concept of Adptivety Rational Equilibrium (A.R.E) where agents base decisions upon predictions of future values of endogenous variables whose actual values are determined by equilibrium equations.

The standard version of "q" theory, in which investment is positively related to marginal "q", breaks down in the presence of fixed costs of adjustment. With fixed costs, q is a non-monotonic function of investment. Therefore its inverse, which is the traditional investment function, does not...