2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/127237We study the energy of relativistic electrons and positrons interacting via the second quantized Coulomb potential in the field of a nucleus of charge Z within the Hartree-Fock approximation. We show that the associated functional has a minimizer. In addition, all minimizers are purely electronic states, they are projections, and fulfill the no-pair Dirac-Fock equations.Mathematical Physics81V45; 34L40text