In this paper we study the welfare effect of a monopoly innovation. Unlike many partial equilibrium models carried out in previous studies, general equilibrium models are constructed and analyzed in greater detail. We discover that technical innovation carried out by a monopolist could...

We study complementarity between product and process innovation in a monopoly setting. First we consider the possibility for the firm to alternatively invest only along one of the two directions and compare the incentives of process vs product innovation. Then we allow the firm to invest...

We model the optimal behaviour of a multiproduct monopolist investing both in process and in product innovation in a dynamic setting. Product innovation reduces the degree of substitutability between any two varieties. First, we find that R&D efforts increase in both directions as the number of...

We examine the persistence of monopolies in markets with innovations when the outcome of research is uncertain. We show that for low success probabilities of research, the incumbent can seldom preempt the potential entrant. Then the efficiency effect outweighs the replacement effect. It is vice...