Why one of the world's greatest living mathematicians suddenly picked on two lightweight institutions like City and Polytechnic universities has been baffling many in the local academic community. The Harvard-based, Chinese University-educated Yau Shing-Tung (below left) was in town a week ago to accept an award. Out of the blue, he made some rather unkind remarks. 'Students from the Polytechnic University are not trying their best ... they are not interested in serious research,' the Fields Medallist (maths' equivalent of a Nobel laureate) was quoted as saying. 'City University and Polytechnic University students are only interested in finding jobs, so they don't need first-rate professors. Their resources could be cut and redistributed to other research universities.' It was as if Albert Einstein thought it was worth his time rounding on some obscure training school in America. CityU has been keeping mum, but Polytechnic's president, Poon Chung-kwong (below right) hit back this week. 'The 19th and 20th centuries have seen many high-quality ivory-tower scholars who left their research papers stored away in libraries - that must not have been terribly useful,' he told reporters. Few things in life are nastier than brawls between academics.