BY NOW, MOST people know who John Nash is, even if they know nothing about his obscure mathematical 'game theory'. New York Times reporter Sylvia Nasar's best-selling 1998 biography of the mathematical genius, A Beautiful Mind, and the new blockbuster film of the same name, are threatening to do to game theory what Albert Einstein did to physics and Bertrand Russell to mathematical logic - make it look almost sexy. The film came in second in the Hong Kong box office last week and the book has been on bookstore chain Page One's bestseller list for weeks. Game theory studies strategies available to competing or partially co-operating players to predict possible outcomes from available options. Economists, political scientists and government planners are among its most frequent users. Cheng Shiu-yuen, a mathematics professor and associate dean of science at the Hong Kong University of Science and Technology, says he has started teaching Nash's Nobel Prize-winning paper in his undergraduate class now students seem to have taken a new interest in the man. 'All 28 lines of proof - it's a very short paper,' says Professor Cheng, also a specialist in the theory. Nash, who was diagnosed with schizophrenia after a mental collapse at the age of 30 but recovered in the early 1990s, has found himself embroiled in a smear campaign after the film was nominated for eight Oscars. Nasar had to write to the Los Angeles Times this month repudiating claims Nash was gay, an anti-Semite and a bad father. To counter the rumours, Nash and his long-suffering wife Alicia agreed to be interviewed on 60 Minutes, to be aired on ATV World at 10pm on Thursday. In the 1950s, Nash published a series of papers which helped lay a firmer foundation for game theory by covering games with counterparts more commonly found in the real world than those considered by early theorists. So Nash examines non-zero sum games, when the rewards or payoffs of a game do not add up to zero - which is when one side takes all and the other loses all. In real life, players rarely lose or gain everything, and there is a level of co-operation or at least tacit understanding and mutual expectations even among bitter rivals. In what is now called the Nash Equilibrium, the mathematician proves that in every game there is a set of strategies, one for each competing player, which yields an outcome such that no player can improve his or her situation by unilaterally switching to another strategy. Professor Cheng said not all was positive about the film, which emphasised the madness rather than the mathematics, reinforcing a popular image of scientists being madmen. Nash was not the first game theorist to make it into a major Hollywood film. John von Neumann, one of the theory's founders who advocated the US launch pre-emptive nuclear strikes against the Russians, served as the real-life model for the title character in Stanley Kubrick's classic satire Dr Strangelove. Both mathematicians might have been brilliant but they were not the nicest of men, which may raise questions about the theory's effects on young minds. Richard Feynman, the late US physicist, once revealed a dark side of the theory: 'Von Neumann gave me a very interesting idea: that you don't have to be responsible for the world that you're in. So I have developed a very powerful sense of social irresponsibility as a result . . . It's made me a very happy man ever since.' He was referring to a game-theoretic situation called 'free-rider', which says if you can evade taxes but enjoy social benefits, or avoid military draft and let others fight in your place, then you should do so. Game theory proves the moralistic secondary school teacher wrong: there are always enough diligent taxpayers and soldiers to sustain the game. Alex Lo is the Post's science correspondent alexlo@scmp.com
