Do chemically saturated antihyperon abundancies signal the quark gluon plasma?

Production and the possible chemical equilibration of strange particles at CERN-SPS energies within a microscopic hadronic transport calculation is reviewed. It is shown in particular that the strange quarks are produced initially via string excitations in the primary, secondary and ternary interactions. The recent idea of antihyperon production by multi-mesonic reactions like n1π + n2K → Y-bar + p corresponding to the inverse of the strong binary baryon-antibaryon annihilation process is discussed. It is argued that by these reactions the (rare) antihyperons are driven towards local chemical equilibrium with pions, nucleons and kaons on a timescale of 1-3 fm/c in the still moderately baryon-dense initial hadronic environment after the termination of the prehadronic string phase. Accordingly this mechanism can provide a convenient explanation for the antihyperon yields at CERN-SPS energies without any need of a deconfined quark gluon plasma phase. (author)