The long-term trends of urbanization suggest: not only have more cities formed, but the leading metropolises have grown larger, with a number of peripheral subcenters developing over time. Conventional models of urban growth are limited, in that commuting cost and congestion eventually result in...

How is long run economic growth related to the endogenous diversity of knowledge? We formulate and study a microeconomic model of knowledge creation, through the interactions among a group of heterogeneous research and development (R&D) workers, embedded in a growth model to address this...

We offer a guide to the recent literature on the problem of fair allocation, and we present various concepts that have been developed in this literature and the various economic environments in the context of which they have been analyzed.