2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41341We show that Dyson resummation schemes based on Baym's $Φ$-derivable approximations can be renormalized with counter term structures solely defined on the vacuum level. First applications to the self-consistent solution of the sunset self-energy in $ϕ^4$-theory are presented.Contribution to the proceedings of the International Workshop XXX on Gross Properties of Nuclei and Nuclear Excitations - Ultrarelativistic Heavy-Ion Collisions, Jan. 13-19, 2002, Hirschegg, Austria 7 Pages LaTeX V2: Added conference information as a footnoteHigh Energy Physics - PhenomenologyNuclear Theorytext