Inter‐state dynamics of invention activities, 1930–2000
用马尔可夫链分析美国48个州1930至2000年人均专利的分布动态，发现知识收敛的证据：分布趋向更集中的极限分布，极端州向中间移动，但收敛速度慢。
Abstract We study the dynamics of the cross‐section distribution of patents per capita for the 48 continental US states from 1930 to 2000 using a discrete‐state Markov chain. We test for and find evidence in favor of the (knowledge) convergence hypothesis. The distribution of patents is converging to a limiting distribution that is significantly more concentrated than its initial distribution. States in the extreme are more mobile than states in the middle of the cross‐sectional distribution and are likely to move to the middle. However, the rate of convergence to the limiting distribution is ‘slow’. Copyright © 2006 John Wiley & Sons, Ltd.