In an extended version of d'Aspremont and Jacquemin's (1988) R&D competition model we find a region where the game is a prisoner's dilemma: firms still invest in R&D but they would obtain a higher profit by not investing at all. In a repeated version of the game, we prove that firms implicitly...

We examine a vertically differentiated duopoly where firms invest in process and product innovation and then compete in prices under full market coverage. We show that (i) process and product innovation are complements (substitutes) for the low-quality (high-quality) firm; (ii) the firm which is...