Boundary triples for the Dirac operator with Coulomb-type spherically symmetric perturbations

We determine explicitly a boundary triple for the Dirac operator H:=-iα·∇+mβ+V(x) in R 3 , for mϵR and V(x)=|x|-1(νI4+μβ-iλαx/|x| β), with ν,μ,λϵR. Consequently, we determine all the self-adjoint realizations of H in terms of the behavior of the functions of their domain in the origin. When supx|x||V(x)|≤1, we discuss the problem of selecting the distinguished extension requiring that its domain is included in the domain of the appropriate quadratic form.