ABSTRACT
Intellectual property rights have a twin effect on the economic system. On the one hand they favour the introduction of new technological knowledge. On the other they reduce competition and eventually may limit the rate of introduction of new knowledge. A trade-off takes place between such positive and negative effects. The application to the economics of knowledge of the notions of an essential facility and the liability rule can correct the balance of the trade-off and contribute to the rate of advance of technological knowledge and its effective use in the economic system. The tuning of exclusive property rights makes it possible to minimise knowledge rents and favour the dissemination and use of knowledge in the economic system, taking advantage of its intrinsic cumulability and complementarity.
