Spin-0 fields and the NP-constants close to spatial infinity in Minkowski spacetime

Newman–Penrose (NP) constants of massless spin-0 fields propagating in Minkowski spacetime are computed close to spatial and null infinity by means Friedrich’s i0-cylinder. Assuming a certain regularity condition on the initial data ensuring that field extends analytically critical sets, it is shown NP at future I+ past I− independent each other. In other words, classical I± stem from different parts given Cauchy hypersurface. contrast, that, using slight generalization constants, associated quantities (i0-cylinder constants) do not require being satisfied give rise conserved determined same piece data, which, turn, correspond terms controlling field. Additionally, how conservation laws with can be exploited construct, flat space, heuristic asymptotic-system expansions, which sensitive logarithmic sets.