I’m in search of a number. No, not that kind of a number – I’ve been happily married for nearly ten years, thank you. The number I’m in search of might actually be more elusive than anything one might hope to be handed in a dark, crowded bar. It is so obscure and difficult to obtain that a mere sixteen (some say seventeen) people have ever obtained this number (though, loosely, I believe that number to be much higher). In fact it is not a single number at all but rather a variable with a minimum (and most desired, but impossible to obtain) value of 1. The lowest known instances of this number, however, are a handful of 3’s. Curious are you? Not enough bad television to watch? This number happens to be the answer to the question: what do Bill Gates, Richard Feynman, Hank Aaron, and Natalie Portman (AKA Padmé Amidala, Darth Vader’s former love interest) have in common?

As it turns out they are all in possession of an Erdös-Bacon number. While most of us in science and mathematics probably have an Erdös number, only a handful of people possess an Erdös-Bacon number.

For the uninitiated, you are in possession of an Erdös number if you can trace a series of collaborations (officially via co-authorship) back to the enigmatic mathematician Paul Erdös. Erdös himself had an Erdös number of 0. Anyone who coauthored a paper with him (and he had at least 509 coauthors) had (or has) an Erdös number of 1. Anyone who coauthored a paper with one of them has an Erdös number of 2, and so on.

My quest to obtain an Erdös number actually began after I had unwittingly obtained one. A decade ago, fresh out of engineering school (which I can’t refer to as “college” with an entirely straight face), I found myself stuffed into an anonymous cubicle somewhere near Washington, DC. It didn’t take long for the Dilbertesque reality of government contracting to suck out my soul. And so, within two years, I, along with my wife who at the time was having her own reality problems at a large DC law firm, decided to – drum roll please – publish a paper. The paper led to a company (which predictably failed) and eventually, via a very circuitous route, to here. But let’s return to that paper for a moment.

My wife and I had three coauthors – a kinesiologist and astronaut from Penn State; my wife’s father, a now retired teacher and school technology specialist; and my own father, a now retired high school English and Drama teacher who has a role to play in this quest a bit later. It is via the kinesiologist that I (and the other authors of that paper) obtained an Erdös number of 6.

Oddly, despite a doctorate in mathematics from St. Andrews (you may be familiar with them from the GAP project or, perhaps, from my former advisors’ pet project, the MacTutor History of Mathematics Archive), that single paper marks my only path to Erdös. I have had virtually no coathors in succeeding years (which may be due to the utter obscurity of my research – I’m a world expert on the unification theories of Sir Arthur Eddington – I’m sorry, I seem to have lost you). Anyway, the point is that I nonetheless have an Erdös number. What I don’t possess is a Bacon number which means I also don’t possess an Erdös-Bacon number which is the sum of one’s separate Erdös and Bacon numbers.

So what’s a Bacon number anyway? If you’re currently ravenous, as am I, this might conjure up images of strips of pork sizzling on a griddle (apologies to “Old Ben” and the 880 pound porker at this year’s Fryeburg Fair in Maine). Or perhaps this conjures up images of the venerable Quantum Pontiff, AKA Dave Bacon, who was recently seen at London’s Royal Society impersonating Newton. In fact, it has nothing to do with either (as far as I know). One’s Bacon number traces a path (officially through film roles, semi-officially through film credits, and unofficially through association) back to actor Kevin Bacon. Now, while I do not formally possess a Bacon number, as of yet, I’ve come close and could claim an unofficial or pseudo-Bacon number based on more than one association.

One of my closest associations stems from the fact that one of my good friends is the nephew (and, until recently, subterranean houseguest) of the president of Warner Brothers. Almost thirteen years ago, while on winter break, this friend and I spent a week relaxing in said uncle’s Malibu beach house which used to belong to the late Steve McQueen (whose son Chad was still the neighbor). As it happens, the week was mostly spent in the company of my friend’s grandmother, so no luck there in obtaining a direct Bacon number, though this friend of mine is currently working for an Australian film company (and his uncle is still Warner Bros. president), so there’s still hope.

Now I happen to have a few other Hollywood connections. As it happens, my hometown of East Aurora, New York has produced a disproportionately high number of Hollywood types. Two of the better known have direct connections to nearly everyone in my family via a local community theatre group, though appearing onstage with an actor (or serving on the crew of a production) does not technically qualify one for a Bacon number. So, despite the fact that the actress who played (the now dead) Mrs. Huber on Desperate Housewives was on the first date I had with my wife (long story), and despite the fact that my wife, a few years later, babysat her nephew (who is now approaching six feet tall), I struck out again.

But the utter irony in all of this is that it is actually conceivable that my father (affectionately known to certain people – primarily former students – as “Beard”) just might have an Erdös-Bacon number. Since he was a coauthor on the same paper as the “astrokinesiologist” (who happens to be one of his former students), he has an Erdös number of 6. Since he was a long-time Drama director and coach (as well as English teacher), a number of his former students have gone on to theatre-related jobs. One, in particular, gave Hollywood a try (you might remember him as creepy lawyer Roy Cohn in a flashback episode of The X-Files or Principal Cole in Donnie Darko). In any case, I have a vague recollection that my father appeared in an independent film (ok, that’s really, really a stretch on more than one level) with him many years ago (I’ll have to confirm this at some point, but if I don’t it makes for a more interesting story). If so, my father – the retired high school English and Drama teacher – would have an Erdös-Bacon number of 8! That’s one better than Natalie Portman (whose Erdös number was obtained under her real name, Natalie Hershlag), and is tied with physicists Fred Alan Wolf and John Hagelin as well as linguist Geoffrey Nunberg.

But I suppose that’s stretching it a bit. In fact, Hank Aaron’s Erdös-Bacon number is also a stretch since it is derived from the fact that Aaron and Erdös once happened to sign the same baseball which doesn’t really count as a publication I suppose. The others are entirely real, though, including Natalie Portman’s. And remember Winnie Cooper from The Wonder Years? That would be Danica McKellar (who more recently appeared on The West Wing), who has an Erdös-Bacon number of 6. And in case you’re wondering who possesses those 3’s, that would be Hank Aaron (if the baseball counts), Paul Erdös himself (his Bacon number is 3), and MIT applied math professor Daniel Kleitman whose Erdös number is 1 (he was one of the 509 coauthors previously mentioned) and whose Bacon number is 2 (thanks to his appearance in and consultation on Good Will Hunting).

And so my quest continues. But I’m still relatively young and my wife thinks I’m rather dashing (at least I hope so). And perhaps, someday, someone will make a film about Eddington