  We make a detailed study of the longitudinal polarization of hyperons and
anti-hyperons in semi-inclusive deep-inelastic lepton-nucleon scattering. We
present the numerical results for spin transfer in quark fragmentation
processes, analyze the possible origins for a difference between the
polarization for hyperon and that for the corresponding anti-hyperon. We
present the results obtained in the case that there is no asymmetry between sea
and anti-sea distribution in nucleon as well as those obtained when such an
asymmetry is taken into account. We compare the results with the available data
such as those from COMPASS and make predictions for future experiments
including those at even higher energies such as at eRHIC.
