Unlike other plays with a mathematical underpinning, *A Disappearing Number* forces the audience to face the reality of mathematics and to try to tangle with some its complexities, subtleties, and mysteries.

The play opens with a professor, Ruth Minnen, writing strings of numbers on a stage equivalent of a blackboard: the sequence 2, 4, 6, 8, . . . , the beginning of the sequence of prime numbers, and more. A narrator shatters the staged illusion, pointing out that everyone on stage is an actor, demonstrating that a door doesn't lead anywhere, showing that the glasses worn by the professor have no lenses. The mathematics on the blackboard is the only thing that is real, he insists.

Yet this reality poses its own puzzles. The sequence of even numbers is completely predictable, but it is also infinite. The sequence of primes is also infinite, but it doesn't have the same predictability. These simple examples lead to more profound mysteries, as Ruth begins describing zeta functions and the Riemann hypothesis, which concerns the distribution of primes.

So begins this imaginatively produced account of Ramanujan's life, which intermingles pieces of his story with the modern-day tale of the romance between Ruth and hedge-fund trader Al Cooper, who manipulates numbers with no sense of the impact of those manipulations on people and society or of the underlying mathematics.

The striking production vividly integrates text, image, and action. It scrambles past, present, and future, fragmenting and reassembling time at a pace so rapid that it is sometimes bewildering and disconcerting.

As it proceeds, the play touches on a variety of mathematical themes, from the startling infinitude of infinities to the more commonplace notion that math is everywhere. It incorporates several famous stories about Ramanujan and Hardy, including Ramanujan's prompt rejoinder to Hardy's comment that

1729 is an uninteresting number: 1729 is the smallest number that is the sum of two positive cubes in two distinct ways.

The collaboration between Ramanujan and Hardy spanned World War I, and one of the more startling figures that the play dramatically cites is the more than 34,000,000 casualties (killed, missing, or wounded) of that war. Towards the end, the play brings Ramanujan's research on

mock theta functions into the realm of modern physics via quantum mechanics and string theory.

*A Disappearing Number* is also about clashes between different cultures—in Ramanujan's perspective on life in an alien England, in the differing viewpoints of a math professor and a bond trader trying to find common ground, in the peaceful and destructive uses of mathematics.

Indeed, so much is packed into the play that it sometimes seems to skip too quickly from one thought or one scene to the next. Yet it also successfully conveys some of the wonder and appeal of mathematical activity for its own sake.

Seeing the play was a fitting conclusion to my first day in India—a memorable day that offered a deliciously chaotic mixture of the old and new and of the commonplace and exotic. The conference setting in a new, high-tech convention center seemed familiar from the innumerable meetings I have attended over the years, with some distinctive variants—a pearl shop open for business, rice-based meals for registered participants, a mathematician lecturing on Indian classical music, and going through security checks for every entry to both the center and the nearby hotel. No aimless wandering allowed!

But the seemingly anarchic traffic was something else entirely. The endlessly weaving and honking gaggles of vehicles—trucks, buses, cars, scooters, auto rickshaws, and more—presented an intriguing lesson in cooperative management. I saw practically no traffic signs or lights, yet drivers somehow manage to get where they want to be, with judicious honking and deft maneuvering—and nary a scratch or dent.

Any trip around the city was a breathtaking, nerve-wracking affair, and I was glad I wasn't the driver, but somehow we arrived. I began to relax a bit—as long as I was in a bus. It opened my eyes to the possibility that tight regulation and firm adherence to rules (hence, imposed predictability) may not always be the only way to go.

As the play demonstrated, seeing things in new ways is an important component of creativity—a jolt out of the familiar and routine. Now that I am out of my usual comfort zone (but not too far out), I can hardly wait for day two.

My title, "English Play," refers to the curious heading under which the play was advertised and described on the

ICM India website and in printed material about the meeting. To get to and from the theater, we boarded buses bearing signs that also read "English Play." And, yes, the play was in English, and it was performed by an English theatre company.