Modular functions were first discovered by the Indian mathematical genius Srinivasa Ramanujan. He has been compared to a bursting supernova, illuminating the darkest, most profound corners of mathematics, before being tragically struck down by tuberculosis at the age of 33. Scattered throughout his notebooks are sets of very obscure equations called modular functions. These are some of the strangest equations ever found and appear only in distant, unrelated branches of mathematics. One of these modular functions, called the Ramanujan function in his honor, appears in string theory as the underlying mathematical theory that shows how strings vibrate in 10 and 26 dimensions.
quoted from: http://www.infoplease.com/cig/theories-universe/how-many-dimensions-there.html
