A Universal String Theory
Nobuyoshi Ohta · Progress of Theoretical Physics Supplement · 1996
We show that any N -extended superstring can be embedded into ( N +1)-extended superstring. The resulting theory can be mapped by a similarity transformation into the direct product of the original superstring and topological sector. This implies that arbitrary superstrings can be obtained by selecting different vacua in a universal superstring . We also demonstrate that the embedding is possible for non-critical superstrings. The “small” N =4 superstring is also shown to belong to this hierarchy of superstrings.