%0 Journal Article %T Infrared Behaviour of Propagators and Vertices %A Frederick T. Hawes %A Pieter Maris %A Craig D. Roberts %J Physics %D 1998 %I arXiv %R 10.1016/S0370-2693(98)01105-8 %X We elucidate constraints imposed by confinement and dynamical chiral symmetry breaking on the infrared behaviour of the dressed-quark and -gluon propagators, and dressed-quark-gluon vertex. In covariant gauges the dressing of the gluon propagator is completely specified by P(k^2):= 1/[1+Pi(k^2)], where Pi(k^2) is the vacuum polarisation. In the absence of particle-like singularities in the dressed-quark-gluon vertex, extant proposals for the dressed-gluon propagator that manifest P(k^2=0)=0 and Max[P(k^2)]~10 neither confine quarks nor break chiral symmetry dynamically. This class includes all existing estimates of P(k^2) via numerical simulations. %U http://arxiv.org/abs/nucl-th/9807056v1