  Graviton and gluon scattering are studied from minimal physical assumptions
such as Poincare and gauge symmetry as well as unitarity. The assumptions lead
to an interesting and surprisingly restrictive set of linear equations. This
shows gluon and graviton scattering to be related in many field and string
theories, explaining and extending several known results. By systematic
analysis exceptional graviton scattering amplitudes are derived which in
general dimensions can not be related to gluon amplitudes. The simplicity of
the formalism guarantees wide further applicability to gauge and gravity
theories.
