N = 2 superstring

N = 2 superstring refers to a specific type of superstring theory characterized by its amount of supersymmetry. In the context of superstring theory, "N" typically denotes the number of supersymmetries that are present in the theory. Therefore, N = 2 superstring theories have a higher amount of supersymmetry compared to theories with lower values of N, such as N = 1 or N = 0.