A general method for determining the target-space symmetries, both broken and unbroken, of string theory is presented. Symmetries are shown to be consequences of a class of automorphisms of the world-sheet operator algebra. This formalism is used to prove general coordinate invariance, two-form gauge invariance, and non-Abelian gauge invariance in heterotic string theory.

• Received 23 January 1989

DOI:https://doi.org/10.1103/PhysRevD.39.3016