Comparison of longitudinal polarization of $\Lambda$ and $\bar\Lambda$ in deep-inelastic scattering at COMPASS

The longitudinal polarization of $\Lambda$ and $\bar{\Lambda}$ hyperons produced in deep-inelastic scattering of 160 GeV/c polarized muons is studied in the COMPASS experiment. Preliminary results on x- and y- dependence of the longitudinal polarization of $\Lambda$ and $\bar{\Lambda}$ from data collected during the 2003 run are presented.