Article 10142 introduced the idea of the renormalization group in quantum field theory. In colloquial terms, the renormalization group describes how a model changes when we "zoom out." Article 22212 derived a system of ordinary differential equations that describe how the coefficients in the action of a scalar quantum field change under the flow of the renormalization group. This article uses those flow equations to study which parts of the action are relevant (becoming more important at lower resolution) and which parts are irrelevant (becoming less important at lower resolution) with respect to the trivial fixed point, where interactions are absent.
