In quantum field theory, we don't yet know how to define most models of interest directly in continuous spacetime. As a workaround, we can define many models of interest by treating spacetime as a lattice, with the understanding that the model is only meant to be used at resolutions much coarser than the lattice scale. This works well because of universality: many of a model's details don't have any significant effect on the model's predictions at such low resolutions. Article 10142 introduced some of the general concepts used in the study of universality. This article introduces a specific method for studying universality in greater quantitative detail.
