Editing Coleman–Mandula theorem (section)

===Conformal symmetry===

The theorem does not apply to a theory of [[massless particle]]s, with these allowing for conformal symmetry as an additional spacetime dependent symmetry.<ref name="Weinberg"/> In particular, the [[algebra over a field|algebra]] of this group is the [[conformal symmetry#commutation relations|conformal algebra]], which consists of the Poincaré algebra together with the commutation relations for the [[homothety|dilaton]] generator and the [[special conformal transformation]]s generator.