How important is monopolistic competition to an understanding of the effects of aggregate demand on output? The authors ask this question at three levels. Can monopolistic competition, by itself, explain why aggregate demand affects output? Can it, together with other imperfections, generate...

The authors analyze economies in which individuals specialize in consumption and production and meet randomly over time in a way that implies that trade must be bilateral and quid pro quo. Nash equilibria in trading strategies are characterized. Certain goods emerge endogenously as media of...

We develop an equilibrium search model that incorporates job-to-job transitions, exhibits instances of replacement hiring, and conceptually distinguishes between job and worker flows. We propose a notion of competitive equilibrium for random-matching environments and study the extent to which it...

The essential function of money is its role as a medium of exchange. The authors formalize this idea using a search-theoretic equilibrium model of the exchange process that captures the "double coincidence of wants problem" with pure barter. One advantage of the framework described here is that...

The authors construct a model of a dynamic economy in which lenders cannot force borrowers to repay their debts unless the debts are secured. In such an economy, durable assets play a dual role: not only are they factors of production but they also serve as collateral for loans. The dynamic...

This paper develops a simple neoclassical model of the business cycle in which the condition of borrowers' balance sheets is a source of output dynamics. The mechanism is that higher borrower net worth reduces the agency costs of financing real capital investments. Business upturns improve net...

A number of authors have argued that the conventional model of unemployment dynamics due to Mortensen and Pissarides has difficulty accounting for the relatively volatile behavior of labor market activity over the business cycle. We address this issue by modifying the Mortensen-Pissarides...