"He was a kind of mathematical troubadour." (Image by Kmhkmh.)

Even in a field marked by eccentricity, mathematician Paul Erdös was an odd number. The Hungarian published more papers than any other mathematician in history, even though he never really had an official post or a home or any money. He just traveled around the world, crashed with an array of academics and worked on seemingly unsolvable problems. He hardly slept or ate. This peripatetic pattern and self-abnegation continued until his death in 1996. An excerpt from Jeremy Bernstein’s 1998 Atlantic essay, which meditates on Paul Hoffman’s biography about the monomaniacal human computer, The Man Who Loved Only Numbers:

“Around 1950, when I was an undergraduate in mathematics at Harvard, my tutor George Mackey remarked that he was having a visitation from Paul Erdös.

I had never heard of Erdös (the correct pronunciation seems to have been ‘air-dish’ although I always used ‘air-dosh’), but Mackey explained that he was a kind of mathematical troubadour. He had no actual position — not because he was not offered them, but because they would interfere with his modus operandi.

Erdös migrated rapidly among 25 or so countries. He carried all his belongings in one small suitcase and a shopping bag, the greater part of which was filled with his mathematical papers and notebooks. He had no interest in clothes and even less in money. He needed three or four hours of sleep. He would arrive at a place and announce, ‘My brain is open,’ then proceed to collaborate with any and every mathematician who could keep up with him.

His collection of interesting unsolved problems in almost every field of mathematics, but especially in the theory of numbers where he probably did his most enduring work, seemed inexhaustible. What was exhaustible was the stamina of the mathematicians he landed on. Erdös would knock at a colleague’s door. ‘Hello’ he’d begin. ‘Let n be prime and letf(n) be defined as…’ After a few days of this, friends would be ready for a vacation.”

Paul Erdös tells an anecdote about a mathematician even odder than himself: