In his article “Professor, teach thyself” (Sept. 3), Chairman of the Press Council of India, Markandey Katju, has cited an incident that took place when he was a judge of the Allahabad High Court. He says he chided a mathematics lecturer, whose case he was hearing, and told him that he was not fit to be even a teacher because he (the lecturer) said one divided by zero was infinity. Justice Katju claims that anything divided by zero is indeterminate. He is wrong and the lecturer was right because any non-zero number divided by zero is infinity. It is zero divided by zero that is indeterminate.
While I can understand the plight of the poor lecturer who did not have the courage to correct the judge hearing his case, I am appalled at the timidity of “some of the top senior academicians” of Jawaharlal Nehru University, to whom Justice Katju narrated the incident. I wonder why they let his fallacy pass unchallenged. Justice Katju must seek out the mathematics lecturer and apologise to him.
Kanan Vihari Jaswal,
I would like to digress from the primary point made in the article — with which I completely agree — and talk about the mathematics lecturer’s answer. “Infinity” is indeed the correct answer to the question posed by Justice Katju to the lecturer. 0/0 is indeterminate because it can take multiple values depending on the limit being calculated (for example 2x/x; x->0 is 2 , 5x/x; x->0 is 5) whereas any finite number divided by 0 (eg 1/0) is an impermissible operation, which is just another way of saying that the result is infinite (an absurdly large number).