We analyze oligopolistic competition in a multi-period dynamic setting for goods with network effects. Two or more infinitely-lived firms produce incompatible products differentiated in their inherent quality. Consumers live for a single period and receive the network effect of the previous...

We study how to reward innovators who build on one another. Rewards come in the form of patents. Because patent rights are scarce, the optimal allocation involves sharing: More than one innovator's patent is in force at a given time. We interpret such allocations as patents that infringe one...

We study an optimal patent problem in the spirit of Hopenhayn, et al (2006), but where all innovations arise from two repeated innovators. Following Hopenhayn, et al (2006) we divide patent regimes into those that are exclusive, in the sense that only one firm ever has a claim on the current...

We study how best to reward innovators whose work builds on earlier innovations. Incentives to innovate are obtained by offering innovators the opportunity to profit from their innovations. Since innovations compete, awarding rights to one innovator reduces the value of the rights to prior...

than that implied by Hopenhayn and Nicolini (1997).

Patents are a useful but imperfect reward for innovation. In sectors like pharmaceuticals, where monopoly distortions seem particularly severe, there is growing international political pressure to identify alternatives to patents that could lower prices. Innovation prizes and other non-patent...

Patents are a useful but imperfect reward for innovation. In sectors like pharmaceuticals, where monopoly distortions seem particularly severe, there is growing international political pressure to identify alternatives to patents that could lower prices. Innovation prizes and other non-patent...

We compute the model numerically to show various possible outcomes. We show solutions where the model eventually leads to relatively equal rewards, and contrast these cases with ones where the long run has persistent differentials. We compute the average reward as a function of the number of...

Many manufacturing industries, including the computer industry, have seen large increases in productivity growth rates and have experienced a reduction in average establishment size. A vintage capital model is introduced which can account for this fact. It is shown that a rise in the rate of...