## The Man who knew Infinity, by Robert Kanigel

*June 2020*Why did Ramanujan attain a legendary status among modern Indian mathematicians? Is it just because he was invited to Cambridge in times when no one could even dream of applying there from British-ruled India and maybe he did a remarkable job there? That doesn't quite sound like a compelling reason from a modern standpoint, wherein thousands of Indian students emigrate to study in world-renowned universities along with scholarships using which, even the poorest of the poor can aspire to harness their talents and make it big. There should be more to that story and Robert Kanigel's 'The Man Who Knew Infinity' filled the missing pieces in my jigsaw puzzle with a story that is aptly deemed as one of the most romantic stories in the history of mathematics. This is one book that I managed to devor in a record time (for me), by eagerly waiting for my bedtime reading each day.

When I mentioned about this wonderful biography to one of my friends, he snubbed with "It was all just his inborn talent.....". Hmmm....if only he knew about the psychological struggles of Ramanujan all his life - from running away from home multiple times in his childhood to a suicide attempt during his stay in England!

The story starts with Ramanujan as a happy-go-lucky guy, whose mathematical talents were already recognized in his high school days by his peers and teachers. Life takes a turn in his college days when he looses interest in anything but mathematics. His failure in other subjects leads to revocation of his scholarship, subsequently coercing him into dropping out of the college. He was no more a superstar in the eyes of his friends that he was until that point. As a dropout, he tries his luck at being a tutor for his fellow college mates and utterly fails in doing so, for his unconventional teaching methodology could not even help the "brightest" students pass their exams. Resented by societal treatment, he stays reclusive and jobless in his home for 5 years obsessively doing what he always loved to do. Later on, these very healthy and productive 5 years in Ramanujan's life would go on to unleash his mathematical genius, paving way for his entrance to Cambridge under the guidance of a bright and upcoming mathematician -G.H. Hardy. Amidst the emotional turmoil induced by foreign land added with his strict observance of brahmanical rites leading to a continual health crisis, Ramanujan manages to produce the amount of mathematics that'd baffle mathematicians of several generations. It became a phenomena that mathematicians would spend their lifetimes trying to decode a slice of his notebook and understand its profound implications. During the same 7-year period, he also ends up receiving the much-coveted fellowship of the Royal Mathematical Society of London, becoming the first Indian to receive the honor and one of the youngest recipients ever. After returning to India due to his ill health, he'd continue doing mathematics with unabated enthusiasm, albeit from his death bed until a year after which he takes a last breath. Interestingly, his work on Mock theta functions during this year would lead to the discovery of a new branch of mathematics and would later prompt mathematical historians to weigh it as his greatest endeavor.

The narration is interesting and is evidently backed by a thorough research on the social, economic and cultural backgrounds of Ramanujan and his mentor - G.H.Hardy. Of course, Ramanujan's story itself is legendary and larger-than-life in nature. The superlatives from Hardy (an intellectual giant himself) and Littlewood of Ramanujan's work surely gave me some goosebumps, some of which I'm listing below:

1) Hardy would say of the sum of infinite series of fractions in Ramanujan's first letter, "They have defeated me completely. I have never seen anything in the least like them before. A single look at them is enough to show that they could only be written down by a mathematician of the highest class. They must be true because, if they were not true, no one would have imagination to invent them".

2) Upon examining Ramanujan's notebook for the first time, Littlewood would say, "I can believe he's at least a Jacobi", whereas Hardy would comment that he can only compare with either Euler or Jacobi.

3) Hardy would rank Ramanujan's letter as "certainly the most remarkable I have ever received and its author a mathematician of highest quality, a man of altogether exceptional originality and power".

4) Hardy would say that if he were to rate mathematicians on a scale of 100, he'd give himself 25, Littlewood 30, David Hilbert 80 and Ramanujan 100.

5) When asked about his greatest contribution to mathematics was, Hardy unhesitatingly replied that is was the discovery of Ramanujan, and called their collaboration "the one romantic incident in my life".

6) The tragedy in Ramanujan's life, as said by Hardy, is that he spent most of his prime time in rediscovering the mathematics that the world has long known.

I can't describe the feeling of elation that I experienced while reading the anecdotes such as the above. The sensation was no less than the whistle-worthy elevation moments that I experienced in some of my favorite movies. I am tickled to know that Ramanujan's thought process, which is dominantly based on the power of intuition than anything, is in great alignment with the way ancient Indian mathematicians conducted their studies. This line of thinking, that emphasizes more on the results that arouse out of deep intuition rather than systematic proofs is in contrast with the ideals of deductive reasoning and objectivity that the west has been upholding for many centuries now. It is delighting to note that unlike 20th century Indian Nobel laureates such as Sir C.V.Raman or Subrahmanyan Chandrasekhar who, despite being Indian by birth, groomed themselves in the west, Ramanujan nurtured his intellect on the soil of the subcontinent through indigenous approaches by staying isolated from the west-inspired education system. In other words, he took off where people like Bhaskara, Brahmagupta left off many many centuries back.

This biography is the story of passion, obsession and hunger. This is the story of how Ramanujan killed his hunger and pain with his hunger for Mathematics. This is the story of an underdog who utilized his talents to the fullest extent possible to achieve an impossible feat. This is also the story that is testament to the fact that the west-inspired education system that the whole world has now adopted now is neither perfect nor the only way and it is possible to reach beyond the pinnacle of human knowledge through alternate means.