“…In works [12,18,37], the optical theorem was used to derive general expressions for the probabilities of the electron-positron pair production by a photon. Note also that, in the works [38,39], the resonant case of the process of electron-positron pair generation in a magnetic field by two photons was considered. In work [40], the 1 and resonant 2 pair creation processes were compared at the parameter values that are typical of the neutron star magnetosphere, and the limiting concentration of cyclotron photons at which the second-order process dominates over the first-order one was determined.…”