Article 89053 introduces a family of models called Yang-Mills theories whose only quantum field is a gauge field. The models are defined by treating spacetime as a lattice, with the understanding that we only care about what the model predicts at resolutions much coarser than the lattice scale. Many models with a nonabelian gauged group in 3- or 4-dimensional spacetime have a property called asymptotic freedom, which is believed to be related to the existence of a nontrivial strict continuum limit. This article uses Yang-Mills theory with gauged group SU(N) to introduce that relationship. This article also clarifies some things about the small-coupling expansion (also called perturbation theory) in models with gauge fields.
