Paul Erdős was an extraordinary mathematical collaborator. He traveled constantly, cross-pollinating the mathematical community. He wrote about 1500 papers and had around 500 coauthors. According to Ron Graham,

He’s still writing papers, actually. He’s slowed down. Because many people

starteda paper with Erdős and have let it lay in a stack some place and didn’t quite get around to it … In the last couple years he’s published three or four papers. Of course he’s been dead almost 15 years, so he’s slowed a bit.

For more on Erdős, listen to Samuel Hansen’s excellent podcast.

**Related posts**:

Six degrees of Paul Erdős

Anti-calculus proposition of Erdős

An elegant proof from Erdős

If you joined someone now in completing & coauthoring an unfinished Erdős paper, would you still get an Erdős number of 1?

So I still have an outside chance of getting my Erdős number below 5? Sweet!

Actually, the fact that I have a finite Erdős number at all says volumes about how highly-connected this graph is. I was in academia for only 5 years, in a peripheral field (Industrial Engineering), and only published half a dozen co-authored refereed publications, at a second- or third-tier department. And yet…

Dan Eastwood suggested that if you have a posthumous paper with Erdős, your Erdős number should be imaginary. This was my response:

“I can’t imagine Erdős would have written a paper with me, but I could imagine writing a paper with someone who did write a paper with Erdős, so maybe the imaginary component of my Erdős number should be 2i. The real part of my Erdős number is 4, so my generalized Erdős number (my Erdős-Eastwood number?) would be 4 + 2i.”

This may also require imagining that a journal will accept your paper.

Should you start receiving imaginary rejection notices, seek immediate help.

As a friend of mine comments, Erdos remains more productive than some living colleagues.