Srinivasa Ramanujan and Operations Research

In Tuesday’s plenary talk by Prof. Suvrajeet Sen at the INFORMS Annual Conference in Nashville, I learned that the great George Dantzig was also a statistician who spoke about the importance of solving planning problems under uncertainty. During a coffee break, I got thinking about famous people with not so well known OR connections. Take Srinivasa Ramanujan. He is famous for the beautiful mathematical results he came up with, and a movie was made about him in 2015. Some of his results found applications several decades later. Tucked away in the book ‘The man who knew infinity‘ by Robert Kanigel is an interesting anecdote about a 14-year old Ramanujan being called upon to solve a complicated and recurring real-life resource-allocation problem that was important to the local community and had immediate value.

Occasionally, his powers were put to good use. Some twelve hundred
students attended the school and each had to be assigned to classrooms,
and to the school’s three dozen or so teachers, while satisfying any special
circumstances peculiar to particular students. At Town High, the senior
math teacher, Ganapathi Subbier, was regularly shackled with the maddening
job—and he would give it to Ramanujan.

We can recognize this as a challenging discrete optimization problem. India has a several milennia old and pragmatic tradition of Ganita (the science of calculation). Ramanujan’s approach comes from this tradition that is rooted in reality, and he was no stranger to complex computations. An indirect connection here is P. C. Mahalanobis, founder of the Indian Statistical Institute. He stayed with Ramanujan in England for a while and there is a famous story of a puzzle he posed to Ramanujan, who not only gave him the answer but also the solution to the general case. P. C. Mahalanobis was a wonderful stats and OR person in his own right. He formulated Linear Programming (operational) models to provide decision support for medium-to-long term planning in a newly independent India, whose future at that point in time was deemed to be uncertain by many other countries.