  Let g = n^- + h + n^+ be a symmetrizable Kac-Moody algebra. Let B(\infty) be
the Kashiwara crystal of U_q(n^-), let \lambda be a dominant integral weight,
let T_\lambda = {t_\lambda} be the crystal with one element of weight \lambda,
and let B(\lambda) \subset B(\infty) \otimes T_\lambda be the crystal of the
integrable representation of highest weight \lambda. We compute the descending
string parameters of an element b \otimes t_\lambda in B(\lambda) in terms of
the Lusztig parameters of b.
