This paper constructs a growth model in which monopolistically competing firms choose the characteristic of their own product from an unbounded product space. While consumers wish to satisfy various needs by purchasing a diverse range of goods, production costs are lower for those goods that are...

Evidence shows that firms build their market position by consistently investing in R&D over time and accumulating knowledge protected by secrecy, patents and other appropriability devices. To explore the macroeconomic implications of this fact, I construct an economy where oligopolistic firms...

We develop a model to analyze the social optimality of growth and product variety. The model contains two sectors, one assembly sector producing a homogeneous consumption good and one intermediate goods sector producing differentiated inputs. Growth results from R&D performed in the intermediate...

We investigate the effects of input variety creation and destruction on both micro- and macroeconomic outcomes using detailed data from Belgium. Our microeconomic analysis establishes that the elasticity of downstream firms' marginal cost to supplier separation captures the area under the input...