Madam, - In response to Lynda Donovan (September 1st), the problem with visualising abstract mathematical concepts is that humans can only contemplate in up to three spatial dimensions. Mathematical concepts, however, can exist in infinitely many more. That is what makes them abstract.
If Ms Donovan has developed a means of "making the abstract concrete" by visualising 4-D concepts, I'd be happy to hear from her. - Yours, etc,
Dr MARK A. PERRY,
Statistics Department,
London School of Economics,
London WC2.
