The Erdős number, honouring the late Hungarian mathematician Paul Erdős /εrdøː∫/,
one of the most prolific writers of mathematical papers, is a way of describing the
"collaborative distance", in regard to mathematical papers, between an author and Erdős.
An author's Erdős number is defined inductively as follows:
 Paul Erdős has an Erdős number of zero.
 The Erdős number of author M is one plus the minimum among the Erdős numbers of all
the authors with whom M coauthored a mathematical paper.
My Erdős number is 3 (upper bound). The track is as follows:
 Paul Erdős
 Andrew M. Odlyzko
 Leonidas J. Guibas
 Michael M. Bronstein
