Complicite's new work, conceived and directed by Simon McBurney, tells several interrelated stories linked by the themes of mathematics, infinity and culture clash. In March 1913 the genius mathematician Srinivasa Ramanujan sails for England, despite his previous reluctance to do so due to the restrictions against foreign travel set by his Brahmin caste. In present-day London, mathematics lecturer Ruth is wooed and won over by an Indian-American hedge fund manager who initially fails to understand what motivates her deep love for the only thing that she sees as "real", that which is left when everything else is gone: pure mathematics, as represented by the work of Ramanujan, whom she idolises.
      The story of Cambridge-based mathematician GH Hardy's coup in getting Ramanujan to come to England to work with him, and their ensuing relationship, is intertwined with the modern-day story in Complicite's hallmark style: actors are stage hands and props, the scenery and music characters in themselves. Equations are written on whiteboards, blackboards and notebooks, and are projected to fill the whole stage. We are transported from university lecture hall to a taxicab navigating the treacherous streets of Mumbai, from Hardy and Ramanujan's office to a train, from Ruth and Al's bedroom to an Indian riverbank, with a few flips of the scenery and simple but effective visual effects. The stage walls, Alex tells us (he is a nuclear physicist, also of Indian extraction), are merely an illusion  as he pushes them away  and the characters we see on stage are merely actors. In the end only the equations matter.
      Ramanujan's story is a remarkable one: introduced to mathematics at ten years of age, he was discovering theorems on his own by the age of thirteen. With little formal training he became one of the key figures in 20th century mathematics and his work, which consists of nearly 4000 results (many of them equations involving infinite series), has gone on to prove instrumental in fields such as crystallography and string theory. He was isolated and unhappy in England, where the difficulties of being a vegetarian during wartime, on top of long-running physical and mental health problems, probably contributed to his early death at the age of 32. His approach was very different from that of Hardy's: where Hardy was rigorous and demanded a proof for every equation, Ramanujan seemed to grab his theories out of thin air (he attributed the inspiration to God): they seemed to present themselves to him as complete entities, and he was also a notoriously fast problem solver.
      Numbers play a large part in A Disappearing Number, as you might expect, and they are what both separate and unite the main characters. Al (the hedge-fund manager) repeatedly attempts to get a BT telephone operator (based at "headquarters", wherever that might be: Mumbai? Bangalore?) to transfer his departed wife's number to his name, and he gets increasingly frustrated when the operator fails to recognise the significance of the number to him. The last four digits of this number (1729) also have significance to Hardy and Ramanujan: Hardy's greeting to Ramanujan at the sanatorium to which he is confined after a suicide attempt (Hardy seems to have been a very matter-of-fact character) was that the number of the cab that brought him there was a dull one. Ramanujan immediately responds that it's not boring at all: "it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways."
      Al's failure to understand Ruth's obsession with mathematics and her motivation for going to India to trace Ramanujan's footsteps, and Hardy's attempts to understand Ramanujan and his methods add some tension to what might otherwise be rather dry subject matter. The difficulty in presenting the story to an audience of mixed ability is evident when the explanation of a particular infinite series (by Ruth in lecturer mode) is met by scattered embarrassed laughter in the audience. As she says, most mathematicians do their greatest work before they're 30 (she's 43) and it is with a sense of regret that I identified with her lack of achievement in the subject.
      A Disappearing Number brings to mind Stoppard's Arcadia, Frayn's Copenhagen and the film A Beautiful Mind, and stands up well in comparison with any of them. The links between East and West, art and science, sanity and madness, life and death, creation and procreation, zero and infinity, are all explored here. To paraphrase Hardy, mathematics gives us patterns as beautiful as those by a poet or painter. Complicite are accomplished painters of the stage.
Roderick Swanston