In this paper, electron–photon scattering in relativistic quantum mechanics is formulated in a symmetrical form by making use of a modified form of the photonwave equation proposed by the author in a previous article, together with the usual form of the Diracwave equation. By solving the coupled wave equations two S matrices are deduced, one with the photonwave function and the other with the Diracwave function. For a given scattering process, either one may be used to give the correct result, if it is obtainable from both. Thus, the symmetry of quantum electrodynamics is explicitly revealed in this formulation.
