Proof is in a duel to the death, philosopher tells rival

A Chinese philosopher last month raised the stakes in an academic feud with an anti-fraud campaigner by challenging him to a science duel - to the death.

The dispute began in April when Li Ming, a philosopher, said he had solved the four-colour theorem using a revolutionary logic system. He dismissed as unverifiable the computer-aided proof obtained in 1976 by Ken Appel and Wolfang Haken. He said that "under the guidance of Laozi (an ancient Chinese thinker) and Kant" he had discovered a proof that could be demonstrated with a pen and paper.

In June, Fang Zhouzi - a crusader against academic fraud - published a critique in which he labelled Mr Li a "philosophy-turned-mathematics-crank". He pointed out errors in Mr Li's articles and insisted that Mr Li's proof should be subject to peer review and published in a journal. Mr Li said that he did not want to publish for fear of plagiarism.

A war of words ensued, online and in print, and in August, Mr Li posted a challenge to Mr Fang on his weblog titled "Let us have a duel!" Mr Li says:

"Fang Zhouzi and I should carry out a civilised duel to the death." He proposed that the China Academy of Sciences host a symposium for him, at which he would demonstrate his "cracking" of the theorem. If the experiment failed, Mr Li would commit suicide; if not, Mr Fang would commit suicide.

But Mr Li's offer has not brought the feuding to a halt. Mr Fang has turned down Mr Li's "deadly wager" on the grounds that scientific results "are built on evidence and logic, not on a duel". Moreover, Mr Fang said, he did not believe that Mr Li would admit to losing a bet.