For example, by imposing supertranslation invariance (using a smaller BMS group acting only on the future or past null infinity) on S-matrix elements involving gravitons, the resulting Ward identities turn out to be equivalent to Weinberg 's 1965 soft graviton theorem. In fact, such a relation between asymptotic symmetries and soft Quantum field theory theorems is not specific to gravitation alone, but is rather a general property of gauge theories including electromagnetism.