Principle of minimal sensitivity
= Principle of minimal sensitivity
{title2=$dO_{\mathrm{trunc}}/d\ln\mu^2=0$}
This prescription selects an arbitrary scale or scheme parameter by making a truncated perturbative observable stationary under its variation. The complete physical observable is independent of the <renormalization scale>, but truncation leaves residual dependence. Stationarity is a prescription, not a guarantee of uniquely optimal accuracy or of a stationary point's existence.