A common interwining relation providing a basis for a unified treatment of three seperate limits at which a Dirac Hamiltonian, with scalar and vector potentials exhibited supersymmetric patterns was discussed. It was shown that in the Coulomb limit, the potentials were 1/r but their strength were otherwise arbitrary. In the pseudospin or spin limits, there were no restrictions on the r dependence of the potentials but a constraint on their sum or differences was there. It was observed that the characteristic degeneracies reflected the presence of additional conserved operators, Johnson-Lippman operator and the relativistic pseudospin and spin generators.
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This work was supported by the Israel Science Foundation.