Innovation and product market concentration: Schumpeter, Arrow and the inverted-U shape curve

We investigate the relationship between market concentration and industry innovative effort within a familiar two-stage model of R&D race in which firms compete à la Cournot in the product market. With the help of numerical simulations, we show that such a setting is rich enough to generate Arrovian, Schumpeterian and inverted-U curves. We interpret these different patterns on the basis of the rela- tive strength of the technological incentive and the strategic incentive.