Schumpeter regarded "The Nature of Capital and Income" as one of the three of Fisher's contributions to general theory generally recognized, at the time Schumpeter was writing, as "of first-class importance and originality." The other two were Fisher's "Mathematical Investigations" (1982) and...

We use the theory of abstract convexity to study adverse-selection principal-agent problems and two-sided matching problems, departing from much of the literature by not requiring quasilinear utility. We formulate and characterize a basic underlying implementation duality. We show how this...

A general and practical competitive market model for trading indivisible goods is introduced. There are a group of buyers and a group of sellers, and several indivisible goods. Each buyer is initially endowed with a sufficient amount of money and each seller is endowed with several units of each...

We propose a nonparametric approach to multiple calibration of numerical general equilibrium models, where counterfactual equilibria are solutions to the Walrasian inequalities. We present efficient approximation schemes for deciding the solvability of Walrasian inequalities.

We show that all the fundamental properties of competitive equilibrium in Marshall's theory of value, as presented in Note XXI of the mathematical appendix to his Principles of Economics (1890), derive from the Strong Law of Demand. This is, existence, uniqueness, optimality, global stability of...

In this paper we examine the structure of the core of a trading economy with three competitive equilibria as the number of traders (N) is varied. We also examine the sensitivity of the multiplicity of equilibria and of the core to variations in individual initial endowments. Computational...

The existence of Nash and Walras equilibrium is proved via Brouwer's Fixed Point Theorem, without recourse to Kakutani's Fixed Point Theorem for correspondences. The domain of the Walras fixed point map is confined to the price simplex, even when there is production and weakly quasi-convex...

I prove an "average" version of the Lyapunov convexity theorem and apply it to establish some core equivalence results for an atomless economy.