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“God has the Big Book,

the beautiful proofs of mathematical theorems are listed here.”

                                                              -- Paul Erdös


Who is Erdos




photographs taken from the documentary N is a Number

by George Paul Csicsery ă

A Hungarian mathematician with no home and no job, Paul Erdös was the incredibly prolific mathematician of the highest caliber. He, who died at age 83 in September 1996, wrote hundreds of mathematical research papers in many different areas, many in collaboration with others. Erdös's motto was not ‘Other cities, other maidens’ but ‘Another roof, another proof.’ He did mathematics in more than 25 different countries, completing important proofs in remote places and sometimes publishing them in equally obscure journals.


Concentrating fully on mathematics, Erdös traveled from meeting to meeting, carrying a half-empty suitcase and staying with mathematicians wherever he went. His colleagues took care of him, lending him money, feeding him, buying him clothes and even doing his taxes. In return, he showered them with ideas and challenges - with problems to be solved and brilliant ways of attacking them.



A biography by The MacTutor History of Mathematics Archive.

Michael D. Lemonick’s article in Times.

Ivars Peterson's article in MAA Online.

Gina Colata’s obituary of Erdös in The New York Times.

The Erdös Number Project - Jerry Grossman's page of Erdös, also contains his effort to track all Erdös' collaborators.
Theory at U of C salutes Paul Erdös - a page by The Computer Science Department at the University of Chicago.





Erdös had a special language all his own, which reveals his dry humor towards politics, death and relationships. 









anyone or anything annoying


classical music

Order Mahler, OM (named after Mahler, one of the worst bridge player in Manchester)

someone performing very poorly




any alcoholic beverage

Do you exist?

Are you awake?



to preach

to give Math lecture

When did you arrive?

When were you born?



to die

to stop doing Math

What was that when it was alive?

What kind of meat is this?



to leave

to die

My brain is open.

I'm ready to do Math.





Your proof is straight from the Big Book.

Erdös' greatest compliment for a mathematician


useless or nasty things





trivial being


Sam and Joe show

international news




child or a little

on the long wavelength






What is an Erdos Number


Erdös number is a way for Mathematicians to explain their connections to Erdös. The number starts with Erdös, who is the only person with Erdös number 0. One has Erdös number 1 if (s)he had published a paper with Erdös; it is 2 if (s)he had published with Erdös’ co-authors, and so on. If there is no chain of co-authorships connecting someone with Erdös, then that person’s Erdös number is said to be infinite (∞).



Stats & Facts

    data retrieved from AMS’ MathSciNet as of 31 May 2007


·   There are about 2.1 million authored items from 1,800 journals in the Mathematical Reviews/MathSciNet database, by a total of about 466,000 different authors.

·   There are nine authors with more than 500 papers: Paul Erdös with 1585, Drumi Bainov (Erdös number 4) with 837, Saharon Shelah (1) with 826, Hari M. Srivastava (2) with 803, Leonard Carlitz (2) with 743, Lucien Godeaux (Ą, he wrote only one joint paper) with 669, Yuri Alekseevich Mitropolskii (3) with 608, Frank Harary (1) with 593, and Richard Bellman (2) with 554.

·   There are five people with more than 200 coauthors: Paul Erdös with 509, Frank Harary (Erdös number 1) with 276, Yuri Alekseevich Mitropolskii (3) with 265, Hari M. Srivastava (2) with 265, and Noga Alon (1) with 260. The other four sociable mathematicians (all have between 155 and 180 coauthors) are: Saharon Shelah (1), Aleksandr Andreevich Samarskii (3), Sergei Petrovich Novikov (3), and Andrei Nikolaevich Kolmogorov (2).

·   There are currently 509 people having written a joint paper with Paul Erdös (who have Erdös number 1) and 6593 people with Erdös number 2.

·   Albert Einstein’s Erdös number is 2; Claude E. Shannon’s and John Nash’s are 3; both Stephen Hawking and Bill Gates have Erdös number 4.




My Erdos Number


photograph from Acta Arithmetica 81 (1997)

My  Erdös number is 3 by virtue of this chain of publications:


1.      Juraj Bosák, Pául Erdös, Alexander Rosa, Decompositions of complete graphs into factors with diameter two. Mat. Casopis Sloven. Akad. Vied 21 (1971), 14-28.


2.      Dean G. Hoffman, Christopher A. Rodger, Alexander Rosa, Maximal sets of $2$-factors and Hamiltonian cycles. J. Combin. Theory Ser. B 57 (1993), no. 1, 69-76.


3.      Mirka Miller, Chris Rodger, Rinovia Simanjuntak, Distance magic labelings of graphs. Australas. J. Combin. 28 (2003), 305-315.


The Erdös Number Project

Erdös on Graphs: His Legacy of Unsolved Problems – a book by Fan Chung and Ron Graham 



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last updated: 31 May 2007