Origin of the violation of the Gottfried sum rule

Using generalized Sullivan processes to generate sea-quark distributions of a nucleon at $Q^2=4\mathrm{}$ ${\mathrm{GeV}}^2$, we find that the recent finding by the New Muon Collaboration on the violation of the Gottfried sum rule can be understood quantitatively, including the shape of $F_2^p\mathrm{}\left(x\right)-F_2^n\mathrm{}\left(x\right)\mathrm{}$ as a function of $x$. The agreement may be seen as a clear evidence toward the validity of a recent suggestion of Hwang, Speth, and Brown that the sea distributions of a hadron, at low and moderate $Q^2$ (at least up to a few ${\mathrm{GeV}}^2$), may be attributed primarily to generalized Sullivan processes.