which can be present in addition to supersymmetry giving a superconformal algebra. Low dimensions In a one or two dimensional theory the only possible scattering is forwards and backwards scattering so analyticity of the scattering angles is no longer possible and the theorem no longer holds. Spacetime dependent internal symmetries are then possible, such as in the massive Thirring model which can admit an infinite tower of conserved charges of ever higher tensorial rank. Quantum groups Models with nonlocal symmetries whose charges do not act on multiparticle states as if they were a tensor product of one-particle states, evade the theorem. Such an evasion is found more generally for quantum group symmetries which avoid the theorem because the corresponding algebra is no longer a Lie algebra. Other limitations For other spacetime symmetries besides the Poincaré group, such as theories with a de Sitter background or non-relativistic field theories with Galilean invariance, the theorem no longer applies. It also does not hold for discrete symmetries, since these are not Lie groups, or for spontaneously broken symmetries since these do not act on the S-matrix level and thus do not commute with the S-matrix. See also Extended supersymmetry Supergroup Supersymmetry algebra Notes Further reading Coleman–Mandula theorem on Scholarpedia Sascha Leonhardt on the Coleman–Mandula theorem Quantum field theory Supersymmetry Theorems in quantum mechanics No-go theorems