Cross-country data reveal that the per capita incomes of the richest countries exceed those of the poorest countries by a factor of thirty-five. We formalize a model with embodied technical change in which newer, more productive vintages of capital coexist with older, less productive vintages. A...

We explore the connection between optimal monetary policy and heterogeneity among agents. We utilize a standard monetary economy with two types of agents that differ in the marginal utility they derive from real money balances-a framework that produces a nondegenerate stationary distribution of...