Paul Krugman has clarified the microeconomic underpinnings of both spatial economic agglomerations and regional imbalances at national and international levels. He has achieved this with a series of remarkably original papers and books that succeed in combining imperfect competition, increasing...

Cities are often viewed as places fostering employment. It is shown that the choice of a particular location within a city is a key factor for the creation of jobs by a new firm. This question is addressed in the context of a standard urban model in which existing firms are established at the...

This Paper proposes a two-region model of endogenous growth, which is a natural combination of a core-periphery model a la Krugman and of a model of endogenous growth a la Grossman/Helpman/Romer. Specifically, we add to the core-periphery model an R&D sector that uses skilled labour to create...

The most salient feature of the spatial economy is the presence of a large variety of economic agglomerations. Our purpose is to review some of the main explanations for this universal phenomenon, as they are proposed in urban economics and modern economic geography. We first show why the...

We address the fundamental question arising in economic geography: why do economic activities agglomerate in a small number of places? The main reasons for the formation of economic clusters involving firms and/or households are analysed: (i) externalities under perfect competition; (ii)...