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Center for Nonlinear Studies |
Cities are now home to a majority of the world’s population, and play a major role in many of the most pressing challenges facing humanity such as climate change, sustainability, and economic recovery. Thus understanding urban dynamics is crucial for effective economic, social, and environmental policy-making. Recent availability of large, consistent data sets enables us to study the structure and dynamics of cities in a more quantitative, mathematical way. Population size and economic diversity, our focus in this paper, are two of the most salient characteristics of urban areas associated with innovation and wealth creation. Here we show that a universal structure to the economic diversity of metropolitan areas in the United States reveals by analyzing the distributions of establishments (work places) – fundamental units of economic analysis. This structure is remarkably robust to different levels of wealth and density implying the existence of a common niche construction and indicating an economic ecosystem common to cities in the U.S. We propose a generalized Yule-Simon model with decreasing new types with the system size to explain the empirical data. Our findings suggest that cities are self-similar not only in terms of their aggregated quantities (such as GDP, patents, crime) but also in their internal abundance structure. The dissimilarity of cities comes out by filling the multifarious economic constitutions in the universal mold. We provide multi-dimensional allometry scaling to capture the hidden order of such dissimilarity, from which, we believe, we can gain insight into the systematic economic merits of agglomeration and the division of labor.
Host: Aric Hagberg, CNLS, 667-1444, hagberg@lanl.gov