Explicit expressions for the singlet g_1 at small x and small Q^2 are
obtained with the total resummation of the leading logarithmic contributions.
It is shown that g_1 practically does not depend on Q^2 in this kinematic
region. In contrast, it would be interesting to investigate its dependence on
the invariant energy 2pq because, being g_1 positive at small 2pq, it can turn
negative at greater values of this variable. The position of the turning point
is sensitive to the ratio between the initial quark and gluon densities, so its
experimental detection would enable to estimate this ratioComment: Section 2 is totally changed, one more ref adde
