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 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...