2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/202674The standard approximations of the Dyson--Schwinger equation lead to complex singularities of the fermion propagator. In three-dimensional QED one can show that this phenomenon might be related to confinement: a confining potential leads to mass-like singularities at complex momenta, and thus to the absence of a mass singularity on the real timelike axis. The correct treatment of the vacuum polarization is essential for the confining nature of QED3.18 pages, REVTeX, 7 uuencoded figures appendedHigh Energy Physics - Phenomenologytext