This paper combines horizontal and vertical innovations to build an endogenous growth model that allows for structural change. Older technologies are continuously replaced by newer ones due to creative destruction and new technologies appear as a result of horizontal innovations and as a result...

This paper introduces the dynamical framework which combines product and process innovations. The model contributes to the theoretical literature on innovations in two ways. First, it permits for the simultaneous dynamics of both types of innovations which is rarely considered in the literature....

This paper studies the question why patents for multi-product monopolies should be finite. The monopolist is developing new versions of the basic product continuously and simultaneously invests into the improvement of all the existing and newly created products, thus optimally managing both...

This paper proposes a reduced form model of dynamic duopoly in the context of heterogeneous innovations framework. Two agents invest into expansion of variety of available products and into the improvement of quality of existing products simultaneously. Every newly introduced product has its own...

This paper proposes a reduced form model of dynamic duopoly in the context of heterogeneous innovations framework. Two agents invest into product and process innovations simultaneously. Every newly introduced product has its own dimension of process-improving innovations and there is a continuum...

This paper introduces the distributed optimal control model which combines quality-improving and variety-enhancing innovations of hetero-geneous type. Each newly invented product has its own dimension of quality and its characteristics are di erent from other invented products.The single agent...