Paul Erdos

Paul Erdos is back in the news again, some years after his death. The reason that Paul Erdos is back in the news is really rather amusing. An example of the way in which this internet, or perhaps this web thing, can set off a storm of people looking for information.

It all started with a slightly obscure (to non mathematicians) joke about Paul Erdos in the (excellent) XKCD site. That joke about Paul Erdos is here.

The joke is that Paul Erdos was a slightly odd mathematician who wrote papers with all sorts of people. Looking at all sorts of problems that could have a mathematical solution. In fact, he became so famous for cooperating with others that there arose the phenomenon of an "Erdos" number. If you had co-authored a paper with Paul Erdos then your Erdos number was 0. If you had co-authored a paper with someone with an Erdos number of 0 then your Erdos number would be 1 and so on.

In the way these things work it now appears that half the scientific universe has an Erdos number of 7 or 8.....OK, that's an exaggeration but.

Some more detail:

Paul Erdős (occasionally spelled Erdos or Erdös; Hungarian: Erdős Pál, pronounced ; 26 March 1913 – 20 September 1996) was an immensely prolific and famously eccentric Hungarian mathematician. With hundreds of collaborators, he worked on problems in combinatorics, graph theory, number theory, classical analysis, approximation theory, set theory, and probability theory.

Some of you will see the similarity between Paul Erdos, the Erdos number, and the game Kevin Bacon. For of course that's where the Kevin Bacon game comes from.

Anyway, there's a gentle amusement in seeing what is happening on the web at the moment. XKCD makes an obscure joke then tens of thousands are frantically interrogating Google to find out what the joke is. But, of course, a joke that needs to be explained isn't funny any more, is it?

(And yes, I did get it without looking it up.)