国際寡占競争下における研究開発政策の動学分析

抄録

The main purpose of this paper is to investigate how dynamic R & D and R & D policy affect an international oligopolistic competition.
Suppose that there is an international rivalry between two firms (i.e., home and foreign firms), both of which export their homogeneous outputs to the third country. Suppose also that initially two firms have equal technology. In order to maximize the discounted sum of profits, two firms should decide how much to invest in R & D and how much to produce outputs.
We start from a simple export rivalry model and make it a dynamic model by introducing cost-reducing R & D made by two firms. Moreover, we allow for the possibility of R & D spillovers between two firms.
In the first part of this paper we formulate the differential games to be solved by two firms, derive and characterize the unique open-loop Nash equilibrium. In the second part of this paper we examine the open-loop Nash equilibrium R & D policies of the two governments.
The following results were obtained:
(1) The stationary state marginal cost of two firms depends on the parameters, that is, demand, spillover, discount rate and R & D cost parameter.
(2) The speed of convergence for the stationary state marginal cost of two firms depends on the parameters, that is, demand, spillover, discount rate and R & D cost parameter.
(3) The optimal trajectories of R & D capitals and investment strategies of two firms depend on the parameters, that is, spillover, discount rate and R & D cost parameter.
(4) The open-loop Nash equilibrium R & D subsidies of the two governments depend on the parameters, that is, spillover, discount rate and R & D cost parameter.
These results lead to the conclusion that the stationary state level of marginal cost depend on the degree of spillover and the optimal R & D subsidies depend on the discount rate and the R & D cost.