Technological Relatedness and Knowledge Space: Entry and Exit of US Cities from Patent Classes

Rigby D. L. Technological relatedness and knowledge space: entry and exit of US cities from patent classes, Regional Studies. US patent and citation data are used to measure technological relatedness between major patent classes in the United States Patent and Trademark Office (USPTO). The technological relatedness measures, constructed as the probability that a patent in class j will cite a patent in class i, form the links of a knowledge...