evidence on the role of these commuting flows in supporting such concentrations of economic activity. Steam railways … quantitatively. In counterfactuals, we find that removing the entire railway network reduces the population and the value of land and … buildings in Greater London by 20 percent or more, and brings down commuting into the City of London from more than 370,000 to …

location of service-sector establishments to measure commuting and non-commuting trips within the Greater Tokyo metropolitan … area. We show that non-commuting trips are frequent, more localized than commuting trips, strongly related to the … changes in travel patterns within the city (because of the different geography of commuting and non-commuting trips) …

after 1920. Using a two-city spatial model, we show that the secular evolution of inter-city and intra-city commuting costs … can account for this. Alternatively, the long-run decline in inter-city shipping costs relative to intra-city commuting …

American metropolitan areas with comparable geographic units in Brazil, China and India. Both Gibrat's Law and Zipf's Law seem … to hold as well in Brazil as in the U.S., but China and India look quite different. In Brazil and China, the implications …

Financial network structure is an important determinant of systemic risk. This paper examines how the U.S. interbank … network evolved over a long and important period that included two key events: the founding of the Federal Reserve and the …, initially reducing overall network concentration. The network became even more focused on Fed cities during the Depression, as …

, summary network parameters (e.g., the degree distribution or transitivity index); and (iii) empirical models of strategic … network formation admitting interdependencies in preferences. Current research challenges and open questions are also …

I build a simple dynamic model of the formation of an international social network of importers and exporters. Firms … can only export into markets in which they have a contact. They acquire new contacts both at random, and via their network …

financial institutions. Focusing on a multi sector economy linked through a supply network, we show how structural properties of … the supply network determine both whether aggregate volatility disappears as the number of sectors increases (i … aggregate output from its mean) to sector-specific volatility and to the structural properties of the supply network …

linked fields. Our analysis uses 1.8 million U.S. patents and their citation properties to map the innovation network and its … strength. Past innovation network structures are calculated using citation patterns across technology classes during 1975 …-1994. The interaction of this pre-existing network structure with patent growth in upstream technology fields has strong …