In the paper the quark?gluon vertex is not treated as a simple， tree?level or one?loop object that can be expanded in powers of the strong coupling. “Non?perturbative” means that the vertex is dressed by the full dynamics of QCD – i.e. all orders of gluon exchange， quark loops， and other strong?interaction effects are taken into account. In practice this is done by solving (or modelling) the Dyson–Schwinger equation for the vertex， or by using an Ansatz that incorporates the momentum?dependent dressing functions that encode dynamical chiral symmetry breaking， confinement， etc. Thus the vertex is obtained from the full， non?perturbative DSE framework rather than from a truncated perturbative expansion.。