  Parton distributions given by deep inelastic lepton scattering (DIS) are not
equal to the probabilities of finding those partons in the parent wave
function. Soft rescattering of the struck parton within the coherence length of
the hard process influences the DIS cross section and gives dynamical phases to
the scattering amplitudes. This gives rise to diffractive DIS, shadowing in
nuclear targets and transverse spin asymmetry.
