Let $M = (X, \mathcal{F}, \mu)$ be D1158: Measure space such that

(i)	$\mathsf{Subnull} = \mathsf{Subnull}(M)$ is the D3804: Set of subnull sets in $M$

Then $\mu$ is a complete measure if and only if \begin{equation} \mathsf{Subnull} \subseteq \mathcal{F} \end{equation}