Sixty-five million sound like a big deal by any standard. That’s the size of the improvement that an online army of collaborating mathematicians has already made to a groundbreaking proof involving pairs of prime numbers, which was first announced just a few weeks ago.
Though the improvement is big, mathematically speaking it amounts to a technicality. Still, the achievement showcases a new way of doing mathematics online. Since the proof appeared, mathematicians from across the world have been locked in an addictive race to tighten it up.
The work relates to a longstanding problem called the twin prime conjecture. A prime number can only be divided by 1 and itself, and twin primes are those just two numbers apart, like 3 and 5, or 29 and 31. The conjecture, put forward in 1849, says there are an infinite number of these pairs, but no one has managed to prove or disprove it.
Last month Yitang Zhang of the University of New Hampshire in Durham took an important step towards this goal by showing there are infinite number of primes that are separated by 70 million or less. It was the first time someone had put an upper limit on the gap between pairs of primes. Since then, mathematicians have been competing online to shrink the limit.