The division of labor between and within countries is driven by two fundamental forces, comparative advantage and increasing returns. We set up a simple Ricardian model with a Marshallian input sharing mechanism to study their interplay. The key insight that emerges is that the interaction...

This paper presents a simple, analytically solvable Chamberlinian agglomeration model. As in the canonical core-periphery (CP) model, two agglomerative forces are at work. However, the present model exhibits a "pitchfork bifurcation" rather than the "tomahawk bifurcation" of the CP model.