In an attempt to clean up an unruly literature, we specify the necessary and sufficient conditions for household optimality in a model where money is the only financial asset and provide the relevant proofs. We use our results to analyze when deflationary bubbles can and cannot exist. Our findings are in contrast to the results in several prominent contributions to the literature. We argue for particular specifications of the no-Ponzi-game restrictions on the representative household's and the government's intertemporal budget constraints in a model with money and bonds. Using the restriction on the household we derive the necessary and sufficient conditions for household optimality. The resulting equilibrium terminal conditions are then used to demonstrate that the existence of bonds does not affect when deflationary bubbles can and cannot occur. This result differs from that in other recent works.

This paper focuses on the demand for money in the United States in the context of five popular locally flexible functional forms—the generalized Leontief, the basic translog, the almost ideal demand system, the Minflex Laurent, and the normalized quadratic reciprocal indirect utility function. We pay explicit attention to the theoretical regularity conditions of positivity, monotonicity, and curvature and argue that much of the older empirical literature ignores economic regularity. We treat the curvature property as a maintained hypothesis and provide a comparison in terms of violations of the regularity conditions and in terms of output in the form of a full set of elasticities. We also provide a policy perspective, in that a strong case can be made for abandoning the simple sum approach to monetary aggregation, on the basis of the low elasticities of substitution among the components of the popular M2 aggregate of money.

In this paper, we investigate incentives, other than altruism, that developed countries have for improving developing country technologies. We propose a simple model of international trade between two regions, in which individuals have preferences over an inferior good and a luxury good. The poor region has a comparative advantage in the production of the inferior good. Even when costly adaptation of the technology to the poor region's characteristics is required—making the technology inappropriate for local use—there are parameter configurations for which the rich region has an incentive to incur this cost. It benefits from a terms-of-trade improvement and from greater specialization in the luxury good. Indeed, there are cases where the rich region would prefer to improve the poor region's technology for producing the inferior good rather than its own. We apply our model to the Green Revolution and provide a quantitative assessment of its welfare effects.

We examine optimal policy in an open-economy model with uncertainty and learning, where monetary policy actions affect the economy through the real exchange rate channel. Our results show that the degree of caution or activism in optimal policy depends on whether central banks are in coordinated or uncoordinated equilibrium. If central banks coordinate their policy actions then activism is optimal. In contrast, if there is no coordination, caution prevails. In the latter case caution is optimal because it helps central banks to avoid exposing themselves to manipulative actions by other central banks.

Peter Diamond is one of the major contributors to economics during the last half century. His many contributions include research on growth, Social Security, public finance more generally, the economics of uncertainty, search theory, in particular, and economic dynamics, in general. This work has shaped the way we think about many economic problems, and the way in which we formalize them. Among his long list of honors and awards, he is a fellow of the Econometric Society, a Guggenheim Fellow, a Fellow of the American Academy of Arts and Sciences, a Member of the National Academy of Sciences, and a Nemmers Prize winner. The National Science Foundation has supported his work for the last 40 years. A recent check indicated 9 books and 132 published articles, and there are few signs of any slowdown.