There are 5 types of supersymmetric string or superstring: I, IIA, IIB, HO, and HE. Their low-energy limits have forms of supergravity, and some of them also have gauge fields. Here are their gauge symmetries: IIA, IIB: No gauge field I, HO: SO(32) HE: E8*E8 The gauge fields are all in the algebras' adjoint representations: SO(32): 496 E8*E8: (248,1) + (1,248) Of these, E8*E8 has gotten a lot of study as a superset of the Standard Model's symmetry -- there are several paths from E8*E8 to the Standard Model. But has there been much work on getting the Standard Model out of SO(32)? I've tried doing that with my Lie-algebra code, and I find it difficult to get it in a fashion comparable to the E8*E8 breakdown. There, the first step is E8 -> E6*SU(3) 248 -> (78,1) + (1,8) + (27,3) + (27*,3*) where the E6 gauge fields are associated with a SU(3) singlet and the chiral multiplets with SU(3) triplets. I can get the Standard Model if I skip this condition, however. I can also get Georgi-Glashow SU(5) or Pati-Salam SO(6)*SO(4), though not SO(10) or E6 -- I can't get a SO(10) spinor, only a vector and an adjoint.