In this paper we analyze an inter-temporal optimization problem of a representative firm that invests in horizontal and vertical innovations and that faces a constraint with respect to total R&D spending. We find that there can exist two different steady-states of the economy when the amount of...

In this paper we analyze the dynamics of an R&D differential game allowing for technological spillovers and sigmoid learning functions of multiproduct oligopolies. We demonstrate how the presence of learning together with spillovers may generate a rich set of outcomes, varying from constant...

In this paper we study the impact of environmental pollution in an endogenous growth model that allows for structural change. The model is based on doubly-differentiated R&D where newer, less polluting technologies gradually replace older ones. The analysis shows that the presence of...

This paper combines horizontal and vertical innovations to generate an endogenous growth model allowing for structural change as an endogenous phenomenon. Every industry is profitable only for a limited period of time, making the effective time of existence of the technology endogenous and...