Aspects of fractional superstrings

We investigate some issues relating to recently proposed fractional superstring theories withD_critical<10. Using the factorization approach of Gepner and Qiu, we systematically rederive the partition functions of theK=4, 8, and 16 theories and examine their spacetime supersymmetry. Generalized GSO projection operators for theK=4 model are found. Uniqueness of the twist field,_K/4^K/4, as source of spacetime fermions is demonstrated.Work supported in part by the U.S. Department of Energy under Contract no. DEAC-0381ER40050