Polarized sea-quark and gluon distribution functions.

With the phenomenologically determined valence-quark spin densities in conjunction with the positivity of the unpolarized parton distributions, we extract the polarized sea-quark (gluon) distribution necessary to interpret the European Muon Collaboration measurement of the polarized proton structure function {ital g}{sub 1}{sup {ital p}}({ital x}) in terms of sea quarks (gluons) alone. We then propose more realistic spin-dependent sea and gluon distribution functions which are parametrized in such a way that the first moment of {ital g}{sub 1}{sup {ital p}}({ital x}) receives almost all contributions from the region {ital x}{gt}0.01. A prediction of the polarized neutron structure function is given.