Portrait of calculated existence
Amathematician is a machine for turning coffee into theorems,' said Paul Erdos, one of the strangest, yet acknowledged as greatest, mathematicians of the century - if not the most prolific. He lived only for mathematics, having few possessions or even his own home, preferring to wander as a guest from one mathematician's home to another.
Uninterested in the normal trappings of life - money from publications or speaking engagements was simply given away - he eschewed even sex, preferring to spend 19 hours a day solving problems. He lived on amphetamines and coffee as he did so. By the time he died, aged 83 in 1996, he had published more than 1,500 papers and his enormous contribution to a whole range of mathematical problems was undisputed.
Other mathematicians pride themselves on their Erdos number. Erdos number 1 is the coveted code for having worked with Erdos himself. An Erdos number of 2 is earned by mathematicians who have published with someone who has published with Erdos and so on, to infinity - which is the Erdos number for non-mathematicians. Einstein had an Erdos number 2. There is even an Internet site run by two mathematicians at Oakland University, Michigan, which tracks the coveted numbers.
In sum, so to speak, it seems almost every mathematician in America and many in Europe have been influenced by Erdos.
The tongue-in-cheek game of Erdos numbers gives some clues to the way this book is written - from the stories of those with high Erdos quotients rather than family members or those who 'merely' remembered him.
Rather than a linear biography from birth to death, the book careers off on a series of tangents. There is very little about Erdos' parents or childhood in Hungary, or even his death. Instead Paul Hoffman builds a convincing picture of Erdos by drawing amusing portraits of an array of other mathematicians and their work - and not all of them had an Erdos number of 1. Hoffman has said elsewhere: 'I use Erdos' life story to introduce non-mathematicians to a cast of remarkable numerati from Archimedes and Pythagoras to Stanislaw Ulam, one of the chief minds behind the Los Alamos nuclear projects.' It is almost as if Erdos is too complex and too eccentric to be tackled as a subject. It is far easier to collate the impressions of those who knew him, although Hoffman did interview Erdos over the last 10 years of his life, even following him on mathematical sojourns.
As those who knew Erdos were almost exclusively mathematicians (excepting the epsilons - Erdos' affectionate word meaning small quantities - for children, for whom he had a soft spot) the picture that emerges is one of great admiration for Erdos and great tolerance for his foibles and his inability to deal with normalities of life, such as getting a carton of tomato juice from the fridge, which others might have found strange and irritating, even intolerable.
Erdos is judged by the standards of other mathematicians - several of whom fairly eccentric themselves - rather than the standards of 'normal' people or a simple biographer. And the picture is surprisingly rich and convincing. Erdos comes across as someone who really enjoyed his life, as someone with a sense of humour and fun. His love of mathematics is infectious and the book is peppered with brain-teasing problems which keeps readers reminded of the power and usefulness of mathematics even in the most mundane aspects of life.
The concentration on anecdotes and descriptions (Hoffman in his acknowledgments calls it oral history) makes it all the more readable, particularly for those who are not mathematicians. But it leaves a host of unanswered questions about Erdos' life. The book does not even attempt to chart his major mathematical discoveries or summarise them.
Often as Hoffman digresses into the life of another mathematician or genius, the reader is left entertained but confused, until Hoffman returns eventually to Erdos, by whom one cannot fail to be riveted.
The Man Who Loved Only Numbers by Paul Hoffman Fourth Estate, $220
