Subbaramiah Minakshisundaram obtained his DSc (1940) from University of Madras specializing in pure mathematics and mathematical physics. He served as the Professor of Mathematical Physics, Department of Mathematical Physics, Andhra University and later Professor, Institute of Advanced Studies. Shimla.
Academic and Research Achievements: Minakshisundaram’s forte lay in summability. Even as a young researcher, he displayed his mastery over Tauberian theorems and summability and the understanding of classical Fourier analysis. One of his earliest works was a generalization of his mentor. Ananda Rau’s theorem. On a suggestion from Fr C Racine, the redoubtable French analyst, Meenakshisundaram studied the topological methods of Schauder and Leray and by applying their fixed-point theorem proved the existence, and in some cases, uniquencess of solutions of parabolic nonlinear partial differential equations. This piece of work led him to the study of a new summation process, which he called Besel summability. In one of his works he grappled with the problems of uniqueness of egen-function expansions using the technique of sub-harmonic functions; also did a great deal of work on analytic number theory. He applied the Epstein zeta function [ Z (s)] for studying asymptotic distribution of eigen-values as also for determining—a field in which T Carleman and A Pleijel did pioneering work. Unlike Carleman, however, Minakshisundaram used Green’s function of the heat equation as the analogue of ‘theta function’. Applying Tauberian arguments, he generalized Carleman’s asymptotic results. A fitting tribute to Minakshisundaram is enshirined in what is described as Minakshisundaram coefficient in Mekean and Singer’s solution of the heat equation, which Minakshisundaram had used. He co-authored a book Typical Means (Oxford University Press, 1952).
Awards and Honours: Minakshisundaram was the Member, Indian Mathematical Society and Institute of Advanced Study, Princeton.