Trade, Competition, and Efficiency

We present a general equilibrium model of monopolistic competition featuring pro-competitive effects and a competitive limit, and investigate the impact of trade on welfare and efficiency. Contrary to the constant elasticity case, in which all gains from trade are due to product diversity, our model allows for a welfare decomposition between gains from product diversity and gains from pro-competition effects. We then show that the market outcome is not efficient because too many firms operate at an inefficiently small scale by charging prices above marginal costs. Using pro-competitive effects and the competitive limit, we finally illustrate that trade raises efficiency by narrowing the gap between the equilibrium utility and the optimal utility.Pro-competitive effects, competitive limit, excess entry, trade and efficiency, monopolistic competition

`Brain drain' without migration: Capital market integration and capital-skill complementarities

We analyze the impacts of capital market integration on the skill composition of labor, using a framework in which heterogeneous agents decide to invest in the acquisition of skills and where production exhibits increasing returns in the available skill range (i.e., capital-skill complementarity).

Survival of the Fittest in Cities: Agglomeration, Selection, and Polarisation

Empirical studies consistently report that labour productivity and TFP rise with city size. The reason is that cities attract the most productive agents, select the best of them, and make the selected ones even more productive via various agglomeration economies. This paper provides a microeconomically founded model of vertical city differentiation in which the latter two mechanisms (`agglomeration' and `selection') operate simultaneously. Our model is both rich and tractable enough to allow for a detailed investigation of when cities emerge, what determines their size, and how they interact through the channels of trade. We then uncover stylised facts and suggestive econometric evidence that are consistent with the most distinctive equilibrium features of our model. We show, in particular, that larger cities are both more productive and more unequal (`polarised'), that inter-city trade is associated with higher income inequalities, and that the proximity of large urban centres inhibits the development of nearby cities.entrepreneur heterogeneity, firm selection, agglomeration, income inequalities, urbanization, urban systems

Do rent-seeking and interregional transfers contribute to urban primacy in sub-Saharan Africa?

We develop an economic geography model where mobile skilled workers choose to either work in a production sector or to become part of an unproductive elite. The elite sets income tax rates to maximize its own welfare by extracting rents, thereby influencing the spatial structure of the economy and changing the available range of consumption goods. We show that either unskilled labor mobility, or rent-seeking behavior, or both, are likely to favor the occurence of agglomeration and of urban primacy. In equilibrium, the elite may tax the unskilled workers but does not tax the skilled workers, and there are rural-urban transfers towards the agglomeration. The size of the elite and the magnitude of the tax burden that falls on the unskilled decrease with product differentiation and with the expenditure share for manufacturing goods. All these results are broadly in line with observed patterns of urban primacy and economic development in sub-Saharan African countries.economic geography; rent-seeking; interregional transfers; urban primacy; Sub-Saharan Africa.

Regional inequality and product variety

We investigate how differences in set-up costs of various types affect the trade-off between global efficiency and spatial equity and show that the standard assumption of symmetry in fixed costs masks the existence of an interesting effect : the range of available varieties varies depends on the spatial distribution of firms. In such a setting, even when the market outcome leads to excessive agglomeration under symmetric fixed costs, a planner opts for asymmetric fixed costs and more agglomeration. The reason is that the losses induced by more agglomeration are offset by the gains due to additional product variety.fixed costs; set-up costs; market size; international trade; homemarket effect