On the classification of (2,1) heterotic strings
arXiv:hep-th/9706122 · doi:10.1016/S0370-2693(97)01156-8
Abstract
We classify all untwisted (2,1) heterotic strings. The only solutions are the three already known cases, having massless spectra consisting either of 24 chiral fermions, or of 24 bosons, or of 8 scalars and 8 fermions of each chirality.
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