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Once SDM told me the following story:
It must be early fifties. Mrs. SDM was having problem with her only delivery. The doctors then decided to try maybe one of the earliest Caesarian Sections in Calcutta. She was in the OT for more than an hour. While SDM was waiting outside, he told me, pointing to his head, that 'it got solved'. He was referring to the 'Majumdar formula' for CG coefficients of the rotation group.
For youngsters who haven't heard of it, there are only four formulae for the CG coefficients of the rotation group: Weyl formula, Van der Warden formula, Racah formula, and Majumdar formula. Each looks different. But they are equivalent. The specialty of Majumdar formula is that it comes from calculus, while the others come from group theory. His is unique. He showed that the weird CG coefficients appear as the coefficients of expansion of a hypergeometric function in a Taylor series. This led to the entire later work of DB and SDM and their students on the ‘master analytic functions' (all of them more complicated hypergeometric functions) of more intricate and important groups, like the Lorentz Group. DB knows all about it.
These four formulae are listed in a Russian book he showed me. He was rightly beaming with pride to be ranked alongside such stalwarts. He was ‘invited' for a Professorship at IIT KGP by Professor H.N.Bose, the then HoD. But the rules of IIT said that he had to appear before a ‘duly constituted selection committee’. He was unhappy, but the then Director Professor S.R.Sengupta was a fan of SDM. So he tried to make light of the formality of an interview. But, one of the members asked SDM what his ‘achievements’ were. SDM told him brusquely to go to the Library, pick up the Angular Momentum book and turn to Page so and so to learn of one of his achievements.
Once he told me somewhat wryly that Mompi, his daughter, refuses to learn math from him. I asked him why. He said he found the prescribed calculus book of Class XI very inadequate, so he started teaching ‘Limits’ for a fortnight. Then she gave up, once for all.
Analysis was his forte. He was past master in that field. And tried to reduce all problems of Physics to Analysis.
Mompi & Angular Momentum
It must be early fifties. Mrs. SDM was having problem with her only delivery. The doctors then decided to try maybe one of the earliest Caesarian Sections in Calcutta. She was in the OT for more than an hour. While SDM was waiting outside, he told me, pointing to his head, that 'it got solved'. He was referring to the 'Majumdar formula' for CG coefficients of the rotation group.
For youngsters who haven't heard of it, there are only four formulae for the CG coefficients of the rotation group: Weyl formula, Van der Warden formula, Racah formula, and Majumdar formula. Each looks different. But they are equivalent. The specialty of Majumdar formula is that it comes from calculus, while the others come from group theory. His is unique. He showed that the weird CG coefficients appear as the coefficients of expansion of a hypergeometric function in a Taylor series. This led to the entire later work of DB and SDM and their students on the ‘master analytic functions' (all of them more complicated hypergeometric functions) of more intricate and important groups, like the Lorentz Group. DB knows all about it.
These four formulae are listed in a Russian book he showed me. He was rightly beaming with pride to be ranked alongside such stalwarts. He was ‘invited' for a Professorship at IIT KGP by Professor H.N.Bose, the then HoD. But the rules of IIT said that he had to appear before a ‘duly constituted selection committee’. He was unhappy, but the then Director Professor S.R.Sengupta was a fan of SDM. So he tried to make light of the formality of an interview. But, one of the members asked SDM what his ‘achievements’ were. SDM told him brusquely to go to the Library, pick up the Angular Momentum book and turn to Page so and so to learn of one of his achievements.
Once he told me somewhat wryly that Mompi, his daughter, refuses to learn math from him. I asked him why. He said he found the prescribed calculus book of Class XI very inadequate, so he started teaching ‘Limits’ for a fortnight. Then she gave up, once for all.
Analysis was his forte. He was past master in that field. And tried to reduce all problems of Physics to Analysis.
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