7 Penrose’s Quasi-Local Energy-Momentum and Angular Momentum
The construction of Penrose is based on twistor-theoretical ideas, and motivated by the linearized
gravity integrals for energy-momentum and angular momentum. Since, however, twistor-theoretical ideas
and basic notions are still considered to be some ‘special knowledge’, the review of the basic idea behind the
Penrose construction is slightly more detailed than that of the others. The basic references of the field are
the volumes [312, 313
] by Penrose and Rindler on ‘Spinors and Spacetime’, especially volume 2, the very
well readable book by Hugget and Tod [206] and the comprehensive review article [377
] by
Tod.