The — Guy Who Knew Infinity

In his last year (1919–20), Ramanujan wrote a “lost notebook” containing mock theta functions—series that mimic theta functions but are not modular forms. Decades later (2002), S. Zwegers showed they arise from the theory of harmonic Maass forms, confirming Ramanujan’s prescience.

He died on April 26, 1920, aged 32. Hardy later wrote, “The tragedy of his life was not that he died young, but that during his one year of health in Cambridge, he had been given only the mediocre theorems to prove.” Ramanujan’s legacy is twofold: mathematical and symbolic. the guy who knew infinity

The partition function p(n) counts the number of ways to write n as a sum of positive integers (order irrelevant). With Hardy, Ramanujan derived an exact asymptotic series that converges to p(n) , astonishing for its use of complex analysis (circle method). This work later became foundational in analytic number theory. In his last year (1919–20), Ramanujan wrote a

Ramanujan discovered remarkable continued fractions, including the Rogers–Ramanujan continued fraction, whose convergence properties and connections to partition identities still inspire research. 5. The Return to India and Final Year (1919–1920) By early 1919, Ramanujan’s health was beyond recovery. He returned to India and spent his last months producing the “lost notebook” (actually a sheaf of 87 loose pages, rediscovered in 1976 by George Andrews). In these pages, written in a shaky hand, he anticipated modern developments in mock theta functions, q-series, and even combinatorics. This period suggests that, far from declining mentally, Ramanujan’s creative powers intensified even as his body failed. He died on April 26, 1920, aged 32

Abstract This paper examines the life, mathematical contributions, and enduring legend of Srinivasa Ramanujan (1887–1920), the self-taught Indian prodigy whose intuitive grasp of numbers reshaped early 20th-century analysis. Drawing primarily from Robert Kanigel’s biography, the paper explores the tensions between Ramanujan’s mystical, formula-driven mathematics and the rigorous, proof-based tradition of Cambridge. It analyzes his collaborations with G.H. Hardy, his key results (partitions, mock theta functions, continued fractions), and the cultural and psychological dimensions of his genius. Finally, it considers the legacy of Ramanujan as both a historical figure and a symbol of cross-cultural scientific exchange. 1. Introduction: The Myth and the Man Few mathematicians have captured the public imagination like Srinivasa Ramanujan. Born in a small village in Tamil Nadu, he produced thousands of theorems, many of them without proof, yet almost all later shown to be correct. His life—a trajectory from near-obscurity and poverty to fellowship at Cambridge University, followed by early death at 32—has become a modern parable of untutored genius. Robert Kanigel’s The Man Who Knew Infinity (1991) remains the definitive biographical treatment, avoiding hagiography while illuminating the psychological, social, and intellectual forces that shaped Ramanujan’s work.

His notebooks have spawned hundreds of research papers. The Ramanujan conjecture (proved by Deligne in 1973 as part of the Weil conjectures) became a cornerstone of modern algebraic geometry. The Hardy–Ramanujan circle method remains a standard tool.

Crucially, Ramanujan had almost no formal training in proof. His methods were idiosyncratic: he would derive a result on a slate, erase it once committed to memory, and then write the final formula in a notebook. This process, while immensely productive, left a legacy of unproven claims. When he wrote to G.H. Hardy at Cambridge in 1913, enclosing a list of theorems, Hardy initially suspected fraud—but was quickly astonished. “A single look at them is enough to show that they could only be written down by a mathematician of the highest class.” — G.H. Hardy The partnership between Ramanujan and Hardy (1877–1947) is one of the most famous in mathematical history. Hardy, a meticulous analyst and atheist, was the perfect foil to Ramanujan’s mystical intuition. Hardy’s role was not to create mathematics with Ramanujan, but to translate Ramanujan’s insights into the language of proof.