Magnetic charges in the AdS(4) superalgebra osp(4 vertical bar 2)

We discuss the issue of how to include magnetic charges in the AdS(4) superalgebra osp(4 vertical bar 2). It is shown that the usual way of introducing a pseudoscalar central charge on the right hand side of the basic anticommutator does not work, because this breaks SO(2, 3) covariance. We propose a way out by promoting the magnetic charge to a vector charge, which amounts to enlarge osp(4 vertical bar 2) to the superconformal algebra su(2, 2 vertical bar 1). The conditions for 1/4, 1/2 and 3/4 BPS states are then analyzed. These states form the boundary of the convex cone associated with the Jordan algebra of 4x4 complex hermitian matrices. An Inonu-Wigner contraction of the constructed superalgebra yields a known extension of the Poincare superalgebra containing electric and magnetic 0-brane charges as well as string-and space-filling 3-brane charges. As an example, we show how some supersymmetric AdS(4) black holes fit into the classification scheme of BPS states.