Zhang Yitang is proof that for mathematicians, life begins at 40
Middle-aged Chinese researcher's prime numbers breakthrough is more evidence that the days of the maths whiz kid are well and truly over
No mathematician should ever allow himself to forget that mathematics, more than any art or science, is a young man's game," the British mathematician G.H. Hardy wrote in A Mathematician's Apology. But the older guys are now catching up.
Since Hardy wrote those lines in 1940, it has been conventional wisdom that mathematical breakthroughs are most often made in a moment of brilliance by a born genius at a young age, rather than an experienced practitioner after decades of work.
Last month, however, Zhang Yitang, a 50-year-old lecturer in mathematics at the University of New Hampshire, defied Hardy's glib assertion. Zhang, who had not published any original work since 2001, submitted a paper to the peer-reviewed Annals of Mathematics in which he solved one of the most longstanding and difficult problems in pure maths. His proof - that there are an infinite number of consecutive pairs of prime numbers (those that are divisible only by 1 and themselves such as 3, 5, 7, 11) separated by less than 70 million - may be meaningless to the layperson, but to number theorists it is earth-shaking.
The fact that Zhang is well into middle age gives hope to legions of mid-career mathematicians oppressed by Hardy's dictum that groundbreaking work in their field should be left to the young.