Erdös number: 4   (smallest known)

Known chains:

Paul Erdös
Noga Alon (1985) Douglas Stinson (1983)
Manuel Blum (1994) Giuseppe Ateniese (1996)
Nicholas Hopper (2001) Yongdae Kim (2000)
Eugene Y. Vasserman (2006, 2007)

See the Erdös Number Project for more information.

Academic genealogy

My full academic genealogy as a (LARGE) image map.

See the Mathematics Genealogy Project for more information. Thanks to Ian Goldberg, my academic cousin 3 times removed, for showing me how to generate this.