Theorems for Sale

In April, an eBay auction offered math and science aficionados a rare opportunity: to link their names, albeit through 5 degrees of separation, with one of the most famous mathematicians of the 20th century. Trumpeting the title "Decrease your Erdös number!" the auction presented bidders with the chance to collaborate on a research project with the seller, who had collaborated with someone who had collaborated with someone who had collaborated with someone who had collaborated with Paul Erdös, the Hungarian mathematical prodigy who died in 1996.

Erdös was an eccentric, legendary figure with no fixed address. He worked with mathematicians all over the globe, coauthoring papers with more than 500 other researchers during his lifetime.