This paper analyses an open economy Ramsey model with an endogenous labour supply without capital. The technology defines an optimal firm size. Changes to the number of firms is subject to adjustment costs, so that the entry dynamics is determined endogenously. We find that there is a short run...

We develop a model of vertical innovation in which firms incur a market entry cost and position themselves in the quality space. Once established, firms compete monopolistically in the quality space, selling to consumers with heterogeneous tastes for quality. Exogenously growing productivities...

In a recent paper, Chiara Fumagalli and Massimo Motta (2006) challenge the idea that an incumbent can foreclose efficient entry in the face of scale economies by using exclusive contracts. They claim that inefficient exclusion does not arise when buyers are homogenous firms that compete...

In the Dixit-Stiglitz model of monopolistic competition, entry of firms is socially too small. Other authors have shown that excess entry is also a possibility with other preferences for diversity. We show that the cost structure and workers's rents can also explain excess entry

Equilibria and optima generally differ in imperfectly competitive markets. While this is well understood theoretically, it is unclear how large the welfare distortions are in the aggregate economy. Do they matter quantitatively? To answer this question, we develop a multi-sector monopolistic...