Russian maths genius Grigory Perelman, who declined a prestigious¹ international award four years ago, is under new pressure to accept a prize.

俄罗斯数学天才格里高利·佩雷尔曼，四年前曾拒绝过一个有声望的国际奖项，目前又面临再次接受一项奖金的压力。

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The Soviet-born mathematician once taught at colleges in the US

A US institute wants to give him $1m (£700,000) for solving one of the world's most complex mathematical problems, the Poincare Conjecture³（庞加莱猜想） .

But it is unclear whether Dr Perelman, a virtual recluse⁴（隐士） , will pick it up.

A children's charity in St Petersburg, where he lives, has urged him to take the money and give it to charity.

Dr Perelman, 43, has cut himself off from the outside world for the past four years, living with his elderly mother in a tiny flat said by neighbours to be infested⁵ with（侵害，骚扰） cockroaches⁶（蟑螂） .

In an open letter on its website, the Warm Home charity called on Dr Perelman to give the cash equivalent of the US Clay Mathematics Institute's $1m Millennium⁷ Prize to Russian charities.

It suggested that the mathematician had already made an ethical⁸ point by turning down the Fields Medal, the world's highest prize in mathematics, in 2006.

Appeal for privacy

The mathematician is reported to have said "I have all I want" when contacted by a reporter this week about the Clay Millennium Prize.

According to the UK's Daily Mail newspaper, he was speaking through the closed door of his flat.

Dr Perelman was the first person to turn down the Fields Medal（菲尔兹奖） , which would have been presented to him at the International Congress of Mathematicians⁹ in Madrid.

"I'm not interested in money or fame," he is quoted to have said at the time.

"I don't want to be on display like an animal in a zoo. I'm not a hero of mathematics. I'm not even that successful; that is why I don't want to have everybody looking at me."

One of Russia's most senior politicians, Federation¹⁰ Council Chairman Sergei Mironov, has appealed for Dr Perelman to be left in peace to make up his own mind.

He suggested that it was "not very decent to look into other people's pockets and count other people's money", Russia's Interfax news agency reports.