 The Bondi mass is also associated with a group of asymptotic symmetries, the BMS group at null infinity.Like the SPI group at spatial infinity, the BMS group at null infinity is infinite-dimensional, and it also has a preferred 4-parameter subgroup of "pure" translations.Another approach to the problem of energy in General Relativity is the use of pseudotensors such as the Landau-Lifshitz pseudotensor.