Analysis On Innovation R&D Spillovers In Duopoly With A Mixed Approach

The technology innovation spillover, as a significant influencing factor of the R&D competition, is now becoming a center issue in the period of technology economics. In order to have a comprehensive theoretical view on different types of innovation spillovers in duopolies of a mixed approach, we build up some practical models, analyzing how the spillovers'influencing equilibrium values in duopolies, such as level of R&D level, yield, profit and welfare.After the review of related researches on R&D spillovers in oligopolistic competition, the paper introduces some typical approaches to explain how innovation spillover matters. According to types of innovation and oligopolistic markets with distinguished characters, we classify four kinds of modeling approaches of R&D spillovers in oligopolistic competition (See Table. 1.1). In the following two chapters of the paper, we focus on two duopoly models with cost-reducing innovation spillover, a pure duopoly and a mixed duopoly (Model I and Model II in Table 1). We introduce innovation spillover as an exogenous variable in a pure duopoly and analyze the results of the influence of the spillover in a corporative and none-corporative R&D competition. In analysis on mixed oligopoly, we explain why state-owned public firms always produce at a comparatively high cost than private firms with a simple mixed duopoly model (without innovation). However, the two-stage competition in a mixed duopoly has a strict hypothesis to the state-owned public firm, so that the duopoly is not stable in equilibrium. We find it necessary to expand the model. And then, we discuss the under-hypotheses of the duopoly with the innovation spillover as an exogenous variable. According to the under-hypotheses, we give the existent quadrant of equilibrium in a mixed duopoly. We expand the model in two aspects, the hypotheses expansion and the competition stages expansion. In order to have a comprehensive view of the spillover, we introduce other variables to represent the different endogenous spillovers in the stage-expansion model. The two expanded models are defined as a mixed approach competition model, in which model I and model II are obviously two linear degeneration of expanded model. Chapter 4 discusses the issue that whether the influence carried out by the spillovers of different innovation forms comes in the same result. The earlier analyses on innovation spillovers in cost-reducing innovation (CRI) and demand-creating innovation (DCI) were carried out in separated models. We...