Justification of relativistic Dirac-Hartree-Fock and configuration interaction

Before knowing that the relativistic Hamiltonian H does allow the existence of bounded states (H is unbounded from below and from above), the existenc e of SCF and beyond SCF solutions had to be assumed as an act of faith vind icated by consistent numerical results. A recent theorem showing the existe nce of such bounded states furnishes a rigorous framework for the relativis tic theory of electronic bounded states.