Answer to last week's quiz

Paul Erdös was a great mathematician. His paper count exceeds that of Euler and is considered as one of the greatest mathematicians (rightly so). All the co-authors of Paul Erdös have Erdös-number (EN from now) as one. If a person does not has paper with Erdös, but has paper with an author with EN one, that person has an EN two. This procedure moves ahead imparting EN to everyone. If you don't qualify for a finite EN, I am unsure about the answer. Infinity seems to be the most sensible answer.

Web resources on Paul Erdös:

More on EN and finding it out: http://www.oakland.edu/enp/

Quote from fellow mathematicians:

Never, mathematicians say, has there been an individual like Paul Erdös. He was one of the century's greatest mathematicians, who posed and solved thorny problems in number theory and other areas and founded the field of discrete mathematics, which is the foundation of computer science. He was also one of the most prolific mathematicians in history, with more than 1,500 papers to his name. And, his friends say, he was also one of the most unusual.

Biography: http://www-history.mcs.st-and.ac.uk/history/Mathematicians/Erdos.html

PS: Some day, I will post some jokes from his life.