Increasing returns and heterogeneity in a spatial economy

Résumé

We study a general equilibrium model of global trade and local migration in a continuous geographical space. Trade is based on the Dixit-Stiglitz model of monopolistic competition. Migration is modelled as a local interaction decision process. Incentives for migration are of two types: homogeneous incentives of the group, associated with the identity of taste for higher utility levels, and heterogeneous incentives, due to idiosyncrasies in location taste. The impact of migration on the regional structure is twofold. First, when driven by utility differentials, it contributes to agglomeration because of the presence of increasing returns. Second, when reflecting heterogeneous individual choices, it fosters regional convergence. Furthermore, the size of agglomerations, when they occur, increases with the taste for variety and the proportion of the manufacturing population, and decreases with transport costs.