Neutrality in the choice of number of firms or level of fixed costs in calibrating an Armington-Krugman-Melitz encompassing module for applied general equilibrium models

This paper shows how an Armington-Krugman-Melitz encompassing module based on Dixon and Rimmer (2012) can be calibrated, and clarifies the choice of initial levels for two kinds of number of firms, or parameter values for two kinds of fixed costs, that enter a Melitz-type specification can be set freely to any preferred value, just as the cases we derive quantities from given value data assuming some of the initial prices to be unity. In consequence, only one kind of additional information, which is on the shape parameter related to productivity, just is required in order to incorporate Melitz-type monopolistic competition and heterogeneous firms into a standard applied general equilibrium model. To be a Krugman-type, nothing is needed. This enables model builders in applied economics to fully enjoy the featured properties of the theoretical models invented by Krugman (1980) and Melitz (2003) in practical policy simulations at low cost.

Does technological progress magnify regional disparities?

We study how technological progress in manufacturing and transportation to-gether with migration costs interact to shape the space-economy. Rising labor productivity in the manufacturing sector fosters the agglomeration of activities, whereas falling transport costs associated with technological and organizational in-novations fosters their dispersion. Since these two forces have been at work for a long time, the final outcome must depend on how drops in the costs of producing and trading goods interact with the various costs borne by migrants. Finally, when labor is heterogeneous, the most efficient workers of the less productive region are the first to move to the more productive region.