Agents expect to trade with each other infinitely often, but face a temporal absence of a coincidence of wants when they meet. Only loans and/or money can facilitate exchange. In small close-knit economies, enduring trade relationships are valued and loans are optimal. In larger economies, with limited communication, information concerning repayment of loans diffuses too slowly to deter agents from reneging unless loans are severely restricted in magnitude. Money has no such redeemability problems, but if Clower constraints bind, loans help supplement money purchases so that both become essential. Roles of various institutions and the historical evolution of media of exchange are explained.

The purpose of this paper is to explore the welfare properties of dynastic equilibria. There are three central findings. First, under relatively weak conditions, welfare optima cannot be implemented as dynastic equilibria with positive levels of transfers. Second, intergenerational altruism ordinarily renders the objectives of social planners dynamically inconsistent, thereby making implementation of welfare optima problematic. Third, if a planner successfully resolves dynamic inconsistency by committing himself to respect the preferences of deceased generations, then, in a specific set of cases, dynastic equilibria are approximately welfare optimal.

In a monetary model, it is shown that if there is a unique Pareto inefficient barter equilibrium, then a monetary equilibrium exists when traders are sufficiently patient. 1.

In many cases, heterogeneous prices occur in price-taking environments. In empirical work, an aggregate price index is often created from such prices and used to explain aggregate supply and derived demands. We show that consistent aggregation places strong restrictions on functional forms which may be used to describe behaviour. Unlike the case of aggregation of consumer income (but similar to the case of aggregation of wages), these functional forms are inconsistent with standard microtheory.

The paper investigates the problem of tariff reform in a small open multi-household economy that only has tariffs and domestic commodity taxes as policy instruments. The concept of a productivity improvement in tariffs and taxes is introduced and conditions for its existence are established. We prove that a Pareto-improving change in tariffs and domestic taxes exists if a productivity-improving change in tariffs exists and if the Weymark condition on the matrix of household demands holds. Conditions are established for particular tariff reforms, such as proportional reductions and reductions of extreme rates, to yield Pareto improvements in welfare.