While the pattern of urban hierarchy tends to conform to the power law, it is not universal. Especially at the country level, we observe significant deviations from the theoretical distribution  . Countries with a primate city, a city that dominates in population size and, usually, economically, have a deficit of intermediate size cities. Examples of primate cities include Paris in France, London in the United Kingdom, and Tokyo in Japan. The history of these countries play a large role in the persistence of their primate city. Particularly, the concentration of political power in one city early on has a large degree of path dependency.
While the pattern of urban hierarchy tends to conform to the power law, it is not universal. Especially at the country level, significant deviations from the theoretical distribution are observed . Countries with a primate city, a city that dominates in population size and, usually, economically, have a deficit of intermediate size cities. Examples of primate cities include Paris in France, London in the United Kingdom, and Tokyo in Japan. The history of these countries play a large role in the persistence of their primate city. Particularly, the concentration of political power in one city early on has a large degree of path dependency.
D
we observe
A
are observed