It may be possible (e.g. in perturbation theory) to monitor how dimensions of UV operators change along the RG flow. In such a situation, one sometimes calls dangerously irrelevant a UV operator whose scaling dimension, while irrelevant at short distances: formula_28 , receives a negative correction along a renormalization group flow, so that the operator becomes relevant at long distances: formula_29. This usage of the term is different from the one originally introduced in statistical physics.