关键词: 产品创新, 价格管制, 网络外部性, 商誉

Abstract: This paper discussed a dynamic control problem of a monopolist who invested in the product innovation and goodwill in a market with network externality and adopted the regulated price. Under the monopoly optimum, it is concluded that there exists a unique stable steady state equilibrium, which is a saddle point. When the symbol of the change rate of investment in improving product quality and goodwill investment is the same (opposite), the two kinds of investment are complementary (substitutable). As the fixed strength of network externality increases with other parameters being kept constant, it is very likely that the steady-state investment of the monopolist in product innovation increases with the product quality. The steady-state equilibrium investments of the monopolist are substitutes when there are some slight variations in product quality in the neighborhood of the steady-state equilibrium.

Key words: product innovation, price regulation, network externality, goodwill