Abstract
With Éliashberg's equations for the two temperature Green's functions of a superconductor, the effect of real phonons on the transition temperature Tc is discussed. The equation derived for TcTc0 describes a temperature-depdendent pair-breaking mechanism that depends on both the real and the imaginary part of the electron-phonon self-energy (Tc0=transitiontemperatureintheabsenceofrealphonons).