“…In particular, the conformal scattering theory (i.e. the geometric scattering theory) has been studied extensively from the early works by Friedlander [25][26][27][28][29], Baez et al [8], Hörmander [37] to recent ones by Mason and Nicolas [49], Joudioux [41,42], Nicolas [59], Mokdad [53,54], Taujanskas [72] and Pham [63,65].…”