CS Seshadri (1932-2020): World-class algebraic geometer, institution-builder and music lover

CS Seshadri, who passed away on July 17 at the age of 88, was an eminent mathematician, a deep connoisseur of Indian classical music, both Carnatic and Hindustani, an institution-builder and a gentle person. Having been his colleague for more than 50 years, first at the Tata Institute of Fundamental Research and later at the Chennai Mathematical Institute, for me it is also a deep personal loss.

Seshadri was among an early batch of mathematics graduate students at the Tata Institute of Fundamental Research in Mumbai, which was founded just before Independence. K Chandrashekharan was then the head of the institute’s school of mathematics. He was an excellent science administrator, inviting top mathematicians from all over the world to visit TIFR and give lectures on topics of contemporary interest.

Laurent Schwartz, a Fields medallist, was among those who visited. He was impressed by the avidity with which students wanted to learn, so he induced many other mathematicians from France to visit the institute, located until the mid-1960s near the Gateway of India in South Mumbai, as well as arranged for bright students to visit Paris and study modern mathematics.

Trip to Paris

Seshadri was among those who were sent to France, in the late 1950s. In Paris, he got an opportunity to discuss mathematics with the great Jean-Pierre Serre, who was one of the architects of an ongoing modernisation of algebraic geometry. During the course of this effort, Serre made a conjecture, which Seshadri solved in the first non-trivial case. I remember how we, younger graduate students, received this news back in Mumbai. We were excited by the development both on behalf of our senior colleague and also because it showed that it was possible for Indian students to perform at the international level.

After a three-year stint in Paris, Seshadri returned to TIFR. In the meanwhile, he had also solved a problem which had arisen in a seminar in Paris held by another great mathematician, Claude Chevalley. Because of these results and achievements by other early students, the fledgling institute in Mumbai soon got recognition both in India and internationally.

Seshadri collaborated with MS Narasimhan, another eminent mathematician who had joined the institute at the same time and whom I had the good luck to have as my doctoral advisor. The two of them produced a pioneering work that became the centrepiece of a subject called the moduli of vector bundles, which had just been initiated by David Mumford, a professor at Harvard University. Under Seshadri’s influence, many students produced interesting results in algebraic geometry, Lie groups and homogeneous spaces.

Seshadri’s joint work with his students V Lakshmibai and C Musili, who later became professors at Northeastern University, Boston, and Central University of Hyderabad respectively, centred on the geometry of homogeneous spaces and representations of algebraic groups, work that became known as standard monomial theory. At the Chennai Mathematical Institute, he collaborated with his student V Balaji and continued to be productive until a couple of years ago, when he faced some health problems.

He lived up to the stereotype of the absent-minded mathematician. Anecdotes about his forgetfulness are legion. Good-natured as he was, he laughed along with everyone else when these were recounted. One story involves his student at TIFR, Chandrasekhar, who was also a great admirer of his. Chandra, as he was known, was very close to Seshadri and his family. One day, a small group of mathematicians from the institute and a foreign visitor had gathered for tea at the canteen. Seshadri was introducing everyone to the foreigner, but stopped when he came to this student. At that moment, he could not recall his name. To relieve the embarrassment, Chandrasekhar said, “I am Chandra.” Seshadri blurted out, “Yes, this is true!”

Seshadri’s achievements did not go unrecognised. He was honoured with the Shanti Swarup Bhatnagar Prize for Science and Technology and Padma Bhushan in India, Chevalier d’Ordre National Mérite in France, Fellowship of the American Mathematical Society in the US, Fellowship of the Royal Society in the UK, and the Third World Academy of Sciences Award, to mention a few.

Branching out

After about three decades at TIFR, Seshadri moved to Chennai for personal reasons, joining the Institute of Mathematical Sciences, another research institute that, like TIFR, accepted students only at the PhD level. An old friend of ours, S Parthasarathy, induced and helped Seshadri to branch out and start an institution with the mission of training undergraduates, besides undertaking research. Parthasarathy was then working at the petrochemical company SPIC in Chennai, and the new institution was called the SPIC Mathematical Institute.

We first got to know Parthasarathy in Mumbai, where he was working with the Indian Railways. He was an aficionado of music and also managed to obtain his doctorate at TIFR while working. Unfortunately, a few years after the new institute came into being, SPIC faced financial difficulties.

But because of Seshadri’s stature, the institute managed to stay afloat, and later prosper, with the help of another music lover and entrepreneur R Thyagarajan, as well as the Central government. Seshadri’s acumen in selecting and gathering fine scientists – mathematicians, computer scientists and later physicists – was crucial for this endeavour, as was his ability to delegate duties appropriately. This institution eventually evolved into the Chennai Mathematical Institute, one of the most well-recognised Indian institutions for mathematics.

In Chennai, Seshadri could give full vent to his other passion: music. He not only attended concerts, but regularly visited the great Carnatic vocalist T Brinda and learnt several compositions. He also invited musicians to perform and lecture at the Chennai institute, underlining the important of the arts in students’ intellectual growth.

His wife, Sundari, was also a fine singer. Unfortunately, she too passed away, last year. They have two sons, Narasimhan and Giridhar.

Early life

Seshadri was born into a lawyer’s family in a village near Kanchipuram town, about 70 km southwest of Chennai and known for its silk saris and temples. His father shifted to nearby Chengalpattu town, and became quite successful. Seshadri was the eldest child and had ten siblings. “We can form a cricket team,” he used to joke. The youngest of them, CS Rajan is also a successful mathematician.

Seshadri did his undergraduate studies at the Loyola College in Chennai. In those days, in Indian universities and colleges, hardly any professors or teachers were conversant with contemporary science. But the head of Loyola’s mathematics department was Father Racine, a Jesuit priest. Racine’s mentor was one of the greatest mathematicians of the 20th century, the Frenchman Elie Cartan. Although Racine was supposedly not an ideal lecturer, he had the ability to identify and encourage gifted students. It was on Racine’s suggestion that Seshadri joined the Tata Institute of Fundamental Research as a graduate student.

Seshadri also often mentioned Professor Narayanan and Professor Krishnamurthy in Loyola College as having been excellent motivators who had an enthusiasm for whatever they had learnt and the ability to communicate their passion to students.

Seshadri’s grandmother had learnt from the great Carnatic singer Naina Pillai in Kanchipuram. Seshadri imbibed his musicality from her. In Mumbai, he learnt music systematically from AS Panchapakesa Iyer, and also visited and learnt from R Rangaramanuja Ayyangar, a veena player who was a well-known musicologist.

Seshadri’s legacy as a first-rate mathematician and the establishment of a top-notch undergraduate institution emulating fine universities in Europe and America is of immense value. It also served to attract some Indian mathematicians who trained in the West to return to India and teach and mentor students here.

S. Ramanan is a mathematician. He retired as a distinguished professor from the Tata Institute of Fundamental Research in 2001, and is an adjunct professor at the Chennai Mathematical Institute.