Moduli space of Chaudhuri-Hockney-Lykken strings

We discuss an orbifold of the toroidally compactified heterotic string which gives a global reduction of the dimension of the moduli space while preserving the supersymmetry. This construction yields the moduli space of the first of a series of reduced rank theories with maximal supersymmetry discovered recently by Chaudhuri, Hockney, and Lykken. Such moduli spaces contain nonsimply laced enhanced symmetry points in any spacetime dimension D10. Precisely in D=4 the set of allowed gauge groups is invariant under electric-magnetic duality, providing further evidence for the S duality of the D=4 heterotic string. 1995 The American Physical Society.