“…Countervailing this notion, however, are models of urban systems, which allow the possibility that neighboring cities have divergent employment cycles. For example, in the evolutionary hierarchy models of Fujita and Mori (1997) and Fujita, Krugman, and Mori (1999), neighboring cities arise out of a single evolutionary process through which one agglomeration center becomes two, each serving a different set of functions within the metro-area economy. If cities with similar functions have similar cycles, and there is a consistent division of functions across metro areas, then cities in the same position on their metro areas hierarchy will have similar cycles.…”