  We study how the components of hadronic wave functions in light-cone
quantization depend on the ultraviolet cut-off by relating them in a systematic
way to the matrix elements of a class of quark-gluon operators between the QCD
vacuum and the hadrons. From this, we derive an infinite set of scale-evolution
equations for the individual contributions to parton distributions from the
Fock expansion. When summed over all the contributions, we recover the
well-known DGLAP equation.
