expected at high energies. In other words the Green’s function depends on some reference momentum value and the numerical simulations, in principle, make measurements not only at low but also at high energies. In the latter case perturbation theory is actually valid there and hence is a reliable complementary tool. Therefore, if the same Green’s function is computed to several loop orders then it ought to be the case that the numerical measurements will overlap at large energies. Given this, it is sometimes the situation when there are accurate large loop order results that the continuum estimate is used to assist with normalizing the lattice measurements.

This brief overview clouds some of the more technical aspects of the overall procedure. For instance, all the operators of interest undergo renormalization. Whilst this is not a major problem, since the formalism to carry out a renormalization has been established for many years now, there is the problem of the relation of a continuum renormalization to what is performed in practice on the lattice. For instance, the standard practice in high energy problems is to dimensionally regularize QCD and then to subtract the resulting divergences, which are manifested as poles in the regularizing 