# What's your Erdos Number? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [October 31, 2005, 9:22pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790 "2005-10-31T21:22:51Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![beergeek279](https://avatars.discourse-cdn.com/v4/letter/b/7ea924/32.png) [@beergeek279](https://boards.straightdope.com/u/beergeek279)\ **Post date:** [October 31, 2005, 9:22pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/1 "2005-10-31T21:22:51Z")
I’m starting to get into my research (graph algorithms) and was discussing with my advisor small-world graphs. Naturally, Erdos numbers came up, and she mentioned an Erdos number of 3. One of my math profs has a 2 and there’s a person in the department with a 1, though I’m not sure if they’re in discrete mathematics or not. So, what’s your Erdos Number? Are there any Erdos numbers of 1 on the SDMB (and if so do you want to publish? :D)? ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [October 31, 2005, 9:27pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/2 "2005-10-31T21:27:43Z")
I looked this up once – I had to contact a group that had this stuff tabulated and wait for a reply – but I don’t recall my number. Unfortunately, it’s not like your Kevin Bacon number. My Erdos number is finite, but not low – I have papers in common with at least two others who have a huge number of connections, so I’m likely connected through more than one path. ---
**Author:** ![DaddyTimesTwo](https://avatars.discourse-cdn.com/v4/letter/d/f07891/32.png) [@DaddyTimesTwo](https://boards.straightdope.com/u/DaddyTimesTwo)\ **Post date:** [October 31, 2005, 9:30pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/3 "2005-10-31T21:30:42Z")
He presented a paper at the university I attended, several years after I graduated. And one of the professors was working on a paper with him, but I never took one of his classes. And I’m guessing that means my Erdos number approaches infinity. ---
**Author:** ![Sattua](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sattua/32/11906_2.png) [@Sattua](https://boards.straightdope.com/u/Sattua)\ **Post date:** [October 31, 2005, 9:31pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/4 "2005-10-31T21:31:05Z")
Mine is 4. ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [October 31, 2005, 9:51pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/5 "2005-10-31T21:51:24Z")
One of my graduate committee members has an Erdos number of 3. As I have published a (non-mathematical) paper with him, my Erdos number is 4. Here’s an easy way to compute an Erdos number: [http://www.ams.org/msnmain/cgd/index.html](http://www.ams.org/msnmain/cgd/index.html) ---
**Author:** ![bluecanary](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bluecanary/32/3614_2.png) [@bluecanary](https://boards.straightdope.com/u/bluecanary)\ **Post date:** [October 31, 2005, 10:09pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/6 "2005-10-31T22:09:49Z")
That site requires some sort of password, **Terminus Est**. ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [October 31, 2005, 10:12pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/7 "2005-10-31T22:12:33Z")
Oh, sorry. I must have been given access based on my Cornell IP. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [October 31, 2005, 10:38pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/8 "2005-10-31T22:38:46Z")
3 (And I’m in CS, not Math.) ---
**Author:** ![MovieMogul](https://avatars.discourse-cdn.com/v4/letter/m/f08c70/32.png) [@MovieMogul](https://boards.straightdope.com/u/MovieMogul)\ **Post date:** [October 31, 2005, 11:25pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/9 "2005-10-31T23:25:15Z")
I thought the thread title referred to [Irv Erdos](http://www.nctimes.com/news/columnists/erdos). The only way I’d have an Erdos # is if it cross-referenced with the IMDB. ---
**Author:** ![Strinka](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/strinka/32/512_2.png) [@Strinka](https://boards.straightdope.com/u/Strinka)\ **Post date:** [October 31, 2005, 11:46pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/10 "2005-10-31T23:46:25Z")
Uh… So, just what is an Erdos number? ---
**Author:** ![HPL](https://avatars.discourse-cdn.com/v4/letter/h/3da27b/32.png) [@HPL](https://boards.straightdope.com/u/HPL)\ **Post date:** [October 31, 2005, 11:56pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/11 "2005-10-31T23:56:08Z")
> [@Strinka](#): > > Uh… > > So, just what is an Erdos number? I’ve been wondering the same thing. Maybe it’s like your rank in the stonecutters? ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [November 1, 2005, 12:01am UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/12 "2005-11-01T00:01:51Z")
> [@Strinka](#): > > Uh… > > So, just what is an Erdos number? Paul Erdos was a renouned mathematician and the author of many papers in the field. The Erdos Number is similar to the Kevin Bacon number: if you coauthored a paper with Erdos, your number is 1. If you coauthored a paper with someone with an Erdos number of 1, your number is 2, etc. The most famous non-mathemetician with an Erdos number of 1 is Hank Aaron. 😉 ---
**Author:** ![MaxTheVool](https://avatars.discourse-cdn.com/v4/letter/m/9fc29f/32.png) [@MaxTheVool](https://boards.straightdope.com/u/MaxTheVool)\ **Post date:** [November 1, 2005, 12:35am UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/13 "2005-11-01T00:35:35Z")
Can Erdos numbers be by inheritance? If so, I have an Erdos number of 1 from my maternal grandfather, along with some hilarious Erdos anecdotes (“I have just proofed a sheorem… what sheorem have you just proofed?”) ---
**Author:** ![Strinka](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/strinka/32/512_2.png) [@Strinka](https://boards.straightdope.com/u/Strinka)\ **Post date:** [November 1, 2005, 12:41am UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/14 "2005-11-01T00:41:54Z")
Ah. Thanks. Mine is infinite then. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [November 1, 2005, 12:58am UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/15 "2005-11-01T00:58:24Z")
[The Erdos Number Project](http://www.oakland.edu/enp/) I haven’t ever published anything, but I have taken classes from at least one guy with Erdos number 1. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [November 1, 2005, 3:49am UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/16 "2005-11-01T03:49:14Z")
My Erdos number is 4. ---
**Author:** ![Hypnagogic\_Jerk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hypnagogic_jerk/32/4252_2.png) [@Hypnagogic\_Jerk](https://boards.straightdope.com/u/Hypnagogic_Jerk)\ **Post date:** [November 1, 2005, 5:56am UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/17 "2005-11-01T05:56:41Z")
Actually, I’ve heard that Erdos (don’t know how to write the appropriate diacritic) numbers are computed only drawing from papers published by two authors. For example, if you publish a paper with someone whose Erdos number is n, you’ll get an Erdos number of n+1 if you and this person are the only authors, but if there are three or more authors, this paper will not count towards your Erdos number. There are also _extended Erdos numbers_ which, as you’d expect, are computed taking into account any joint paper with other authors, regardless of their number. I personally might have a finite Erdos number, but I don’t know what it is, and it is probably rather high anyway. “High” is relative: it is estimated that a very large majority of people who have a finite Erdos number actually have it smaller than 15. This said, can someone tell me what paper Hank Aaron published jointly with Paul Erdos? And maybe send me a link to it, if it is possible? ---
**Author:** ![beergeek279](https://avatars.discourse-cdn.com/v4/letter/b/7ea924/32.png) [@beergeek279](https://boards.straightdope.com/u/beergeek279)\ **Post date:** [November 1, 2005, 6:04am UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/18 "2005-11-01T06:04:38Z")
> [@severus](#): > > This said, can someone tell me what paper Hank Aaron published jointly with Paul Erdos? And maybe send me a link to it, if it is possible? It’s generally a joke…at an event (I think it was at Emory University, IIRC), Paul Erdos and Henry Aaron signed the same baseball, so you could say they “co-published” and thus Aaron has an Erdos number of 1. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [November 1, 2005, 12:49pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/19 "2005-11-01T12:49:27Z")
severus writes: \> Actually, I’ve heard that Erdos (don’t know how to write the appropriate \> diacritic) numbers are computed only drawing from papers published by two \> authors. I’ve never heard that before. Every description of how the Erdos number works I’ve heard up to now says that you can connect via any co-authored paper, regardless of the number of co-authors. I just checked the only two books I own that might speak to this issue, the two biographies of Erdos (yes, there are two biographies of Erdos), and they both say that any co-authored paper is O.K., regardless of the number of co-authors. \> “High” is relative: it is estimated that a very large majority of people who have \> a finite Erdos number actually have it smaller than 15. Indeed, one of the biographies claims that it’s rare to have a (finite) Erdos number over 7. ---
**Author:** ![BobLibDem](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/boblibdem/32/3149_2.png) [@BobLibDem](https://boards.straightdope.com/u/BobLibDem)\ **Post date:** [November 1, 2005, 12:53pm UTC](https://boards.straightdope.com/t/whats-your-erdos-number/328790/20 "2005-11-01T12:53:19Z")
So exactly what makes this Erdos fellow so important? [Next page](https://boards.straightdope.com/t/whats-your-erdos-number/328790.md?page=2)