GROWTH,INTER‐INDUSTRY AND INTRA‐INDUSTRY COMPETITION AND WELFARE*

In this paper we introduce strategic interaction between firms in an R&D growth model which captures both the intra‐industry competition between firms operating within an industry and the inter‐industry competition between firms in different industries. We show that the more substitutable the goods produced within each industry (across industries) are, that is, the more intense the intra‐industry (inter‐industry) competition, the higher is the growth rate. In the comparison between social optimum and a decentralized economy, it is shown that the market outcome is characterized by inefficiently high entry of firms within each industry and insufficient productivity growth.