  We show that $SU_q(2)$ invariant systems in one and two dimensions exhibit
Bose-Einstein condensation for $q >1$. For these systems there is a
$\lambda$-transition at the critical temperature. The critical temperature and
the gap in the heat capacity increase more rapidly for small deviations from
the standard value $q=1$, and they become approximately constant for large
values of $q$. For low temperatures and $q>1$ the entropy is lower than the
entropy of an ideal Bose gas.
