In active investment climates where firms sequentially improve each other's products, a patent can terminate either because it expires or because a noninfringing innovation displaces its product in the market. We define the length of time until one of these happens as the effective patent life,...

New economic geography focuses on the impact of falling transport costs on the spatial distribution of activities. However, it disregards the role of technological innovations, which are central to modern economic growth, as well as the role of migration costs, which are a strong impediment to...