City sizes and industry concentration

In a general equilibrium model of trade under transportation costs between two cities we show how the relative population sizes are simultaneously detemined with the degree of geographic concentration of industries characterized by different elasticities of scale of production. The effect on city size of the presence of nontraded goods is also analyzed.

Duplication of R&D and industry concentration

The purpose of the literature on Research Joint Ventures (RJV), pioneered by DíAspremont and Jacquemin (1988) and Kamien, Muller, and Zang (1992), has been to combine the best of two worlds: to appropriately deal with R&D spillovers while preserving competition in the product market. Moreover, RJVs eliminate duplication of R&D. Thus, at least in theory, RJVs dominate other solutions such as subsidies. If, however, we are concerned about risks of cartelization, then Spenceís (1984) subsidy-based solution for independently acting firms, is a viable alternative that cannot be dismissed. Indeed, in contrast to the previous literature, we find that in the presence of R&D subsidies, market performance may unambiguously improve with the number of firms in the market.

City sizes and industry concentration

In a general equilibrium model of trade under transportation costs between two cities we show how the relative population sizes are simultaneously determined with the degree of geographic concentration of industries characterized by different elasticities of scale of production. The effect on city size of the presence of nontraded goods is also analyzed .