Empirical studies have found that enhanced foreign competition can encourage or discourage innovation. To address this relationship, I examine a market structure in which a small number of large multi-product oligopolists compete with a large number of small single-product firms in the same...

Forward-looking investments determine the resilience of firms' supply chains. Such investments confer externalities on other firms in the production network. We compare the equilibrium and optimal allocations in a general equilibrium model with an arbitrary number of vertical production tiers....

During the last two decades, new research has greatly advanced our understanding of the structure of world trade. This article reviews the empirical literature that grew out of this effort, emphasizing the ways in which it relied on theoretical developments

In this paper we study how aggregate output responds to the arrival of a new General Purpose Technology (GPT) by looking at adjustment mechanisms that operate through labor markets. We show that under a wide set of circumstances the arrival of a new GPT that raises long-run output can trigger a...

History and theory alike suggest that General Purpose Technologies (GPT's), such as the steam engine or electricity, may play a key role in economic growth. In a previous paper (Helpman and Trajtenberg, 1994) we incorporated this notion into a Grossman-Helpman growth model, and explored the...

We study the politics of intergenerational redistribution in an overlapping generations model with short-lived governments. The successive governmentsþwho care about the welfare of the currently living generations and possibly about campaign contributionsþare unable to pre-commit the future...

We examine the extent to which developing countries that do little, if any research and development themselves benefit from R&D that is performed in the industrial countries. By trading with an industrial country that has large 'stocks of knowledge' from its cumulative R&D activities, a...