Gauge symmetry in string theory

Abstract

An account is given of the way symmetry is incorporated into string theory by using the Frenkel—Kac—Segal mechanism, taken from the representation theory of affine Kac-Moody algebras. The intrinsically quantum mechanical nature of this mechanism is emphasized, and the present stage of development of string theory is compared with the ‘old quantum theory’. The corresponding method of incorporating gauge symmetry into superstring theories is discussed and arguments that appear to prevent the construction of realistic theories of this type are reviewed in outline.