The Erdős number () describes the "collaborative distance" between a person and mathematician Paul Erdős, as measured by authorship of mathematical papers.
The same principle has been proposed for other eminent people in other fields.
Overview
Paul Erdős (1913–1996) was an influential mathematician who spent a large portion of his later life living out of a suitcase, and writing papers with those of his colleagues willing to give him room and board. He published more papers during his lifetime (at least 1,525) than any other mathematician in history.
The idea of the Erdős number was ...