World's cleverest man turns down $1million prize after solving one of mathematics' greatest puzzles

A Russian awarded $1million (£666,000) for solving one of the most intractable problems in mathematics said yesterday that he does not want the money. Said to be the world's cleverest man, Dr Grigory Perelman, 44, lives as a recluse in a bare cockroach-infested flat in St Petersburg. He said through the closed door: 'I have all I want.'

It was in 2002 that Perelman, then a researcher at the Steklov Institute of Mathematics in St. Petersburg, began posting papers online suggesting he had solved the Poincare Conjecture, one of seven major mathematical puzzles for which the Clay Institute is offering $1 million each. Rigorous tests proved he was correct. The topological conundrum essentially states that any three-dimensional space without holes in it is equivalent to a stretched sphere. The puzzle was more than 100 years old when Perelman solved it - and could help determine the shape of the universe.