A NEW GRAVITATIONAL ENERGY-MOMENTUM PSEUDOTENSOR IN TETRAD FORM

It is shown that (1) the new gravitational energy-momentum pseudotenso r t(i)(k)(x) derived from the Hayashi-Shirafuji gravitational Lagrangi an density in the extended Weitzenbock spacetime is the unique theory which can give the gravitational energy()) within any spatial region a definite value independent of the spatial coordinate system and sati sfy certain other physical postulates, and (2) t(0)(0)(x) takes nonneg ative values at any point in spacetime where g(00)>0(*)) for some wel l-known gravitational fields.