ABSTRACT
Loop integrals typically give rise to infinities, which can be regularised by considering a cutoff in momentum space. Another possibility of regularising the theory is by discretising space-time, amounting to a lattice formulation. The parameters, like the coupling constants, masses and field renormalisation constants, will depend on this cutoff parameter, generically denoted by an energy or a distance. For the renormalisation of the coupling constant, it is best to define the physical coupling constant in terms of a particular scattering process, as that is what can be measured in experiment. By adjusting the bare coupling constants of the theory as a function of the cutoff, to ensure that all regularised couplings stay finite when the cutoff is moved to infinity, the calculations can be arranged such that nowhere explicit infinities occur.
