The **Erd****ös number** honors the late Hungarian
mathematician Paul Erdös, one of the most prolific writers of mathematical papers. It
is a way of describing the "collaborative distance", in regard to
mathematical papers, between an author and Erdös.

"And What Is Your Erdös Number?", Casper Goffman, American Mathematical Monthly, Vol. 76, No. 7 (August-September 1969), p. 791.

My Erdös number is 5, since I coauthored a paper with Bart Childs, and his Erdös number is 4, etc., down to Paul Erdös himself, who has an Erdös number of zero. Actually, I should say that my Erdös number is no more than 5, since there may be a shorter path that I haven't found yet.

McGuire ---> Childs ---> Osborne ---> Turlach ---> Vijayan ---> Erdös

McGuire,
Tim; Childs,
Bart An analysis of power series operators. *Appl. Math. Lett.* 4
(1991),
no.
2, 45--48.

Childs,
S. Bart; Osborne,
Michael R. Fitting solutions of ordinary differential
equations to observed data. *Computational techniques and
applications: CTAC95 (Melbourne, 1995), *193--198, *World Sci. Publ.,
River Edge, NJ,* 1996.

Osborne,
Michael R.; Presnell,
Brett; Turlach,
Berwin A. On the LASSO and its dual. *J. Comput. Graph. Statist.* 9
(2000),
no.
2, 319--337.

Czarn,
Andrew; MacNish,
Cara; Vijayan,
Kaipillil; Turlach,
Berwin Statistical exploratory analysis of genetic
algorithms: the influence of Gray codes upon the difficulty of a problem.
*AI 2004: Advances in artificial intelligence, *1246--1252, Lecture
Notes in Comput. Sci., 3339, *Springer, Berlin,* 2004.

Caccetta,
L.; Erdös,
P.; Vijayan,
K. On graphs with adjacent vertices of large degree.
*J. Combin. Math. Combin. Comput.* 5
(1989),
217--222.