We examine the implications of arbitrage in a market with many assets. The absence of arbitrage opportunities implies that the linear functionals that give the mean and cost of a portfolio are continuous; hence there exist unique portfolios that represent these functionals. These portfolios span...

This article compares two leading models of asset pricing: the capital asset pricing model (CAPM) and the arbitrage pricing theory (APT): I argue that while the APT is compatible with the data available for testing theories of asset pricing, the CAPM is not. In reaching this conclusion emphasis...

This paper presents a general model of the demand for differentiated products which has as special cases two popular models used to analyze welfare and competition in monopolistically competitive markets: the model of spatial competition and the symmetric aggregate benefit function approach. The...

Higher education has many of the attributes of a competitive industry. Many enterprises compete for inputs and sell similar outputs to a great variety of buyers. The competitive perspective has not been much used in the analysis of higher education. In this paper we find such a point of view...

Tax and transfer programs transform before-tax income into after-tax income. Income is variable and the tax and transfer system is nonlinear-i.e., marginal tax rates vary. We show that, as a consequence, the tax and transfer system punishes (and rewards) income variability. We calculate the...

Many services provide outputs that depend partially on the customers as inputs; the presence of other customers often contributes to the output experienced by each purchaser. Higher education is the premier example; others are legion. The authors provide a simple model that addresses the...