One of our favorite comics recently had this comic:

What in the heck is it talking about?  One of the most prolific mathematicians of all time was Paul Erdos.  He has been an author on 1590 papers so far (keep in mind that for most math professors, writing 100 papers is considered very impressive!).  The most recent one was in 2008, despite the fact that he passed away in 1996!  He was generally regarded as as a kind, brilliant, and completely eccentric person.  We’ve already mentioned him here and here.

One thing which we haven’t mentioned is the famous (among mathematicians, anyway 🙂 ) notion of a person’s Erdos Number.  If you’ve coauthored a paper with Erdos, then your Erdos number is 1.  If you’ve coauthored a paper with someone who’s coauthored a paper with Erdos, then your Erdos number is two.  And so on.   Bonus points if you can determine Erdos’s Erdos number!

It is a source of pride to have a low Erdos number.  If you’d like to know your professors’ Erdos number, you can go to MathSciNet and under Free Tools you can use the Collaboration Distance function.  For example, yours truly has an Erdos number of four (most mathematicians are in the 3-7 range).  It’s quite fun to play with the Collaboration Distance function and compute the distance between people.  For example, the collaboration distance between Paul Goodey and Einstein is four (Goodey –> Rosenfeld –> Bollobas –> Straus –> Einstein).

P.S.  To use MathSciNet you have to use your 4 + 4 to log into the OU library first because it’s a subscription service of the University.

P.P.S.  If you’d like an Erdos number of one, you had better not depend on the xkcd technique.  It’s well known that the living dead don’t need to solve world problems:

## 3 thoughts on “What’s your Erdos Number?”

1. If you expand the criteria to include general research papers, rather than strictly Mathematical collaboration, then apparently Natalie Portman has a lower Erdös number than any other member of the cast of Mr. Magorium’s Wonder Emporium–at least according to Wikipedia (caveat lector):

[1] **Baird AA**, Kagan J, Gaudette T, Walz KA, __Hershlag N__, Boas DA (Aug 2002). “Frontal lobe activation during object permanence: data from near-infrared spectroscopy”. Neuroimage 16 (4): 1120–5

Above, Hershlag, N. is her legal name.

[2] **Baird AA**, Colvin MK, Vanhorn JD, Inati S, **Gazzaniga MS** (Apr 2005). “Functional connectivity: integrating behavioral, diffusion tensor imaging, and functional magnetic resonance imaging data sets”. J Cogn Neurosci 17 (4): 687–93

[3] **Victor, J.D.**, Maiese, K., Shapley, R., Sidtis, J., and **Gazzaniga, M.S.** (1989) Acquired central dyschromatopsia: analysis of a case with preservation of color discrimination. Clinical Vision Sciences 4, 183-196

[4] Azor, R., **Gillis, J.**, and **Victor, J.D.** (1982) Combinatorial applications of Hermite polynomials. SIAM Journal on Mathematical Analysis 13, 879-890

[5] __P. Erdos__ and **J. Gillis**, “Note on the transfinite diameter,” J. Lond. Math. Soc. 12 185 (1937)