Let $M = (X, \mathcal{F}, \mu, T)$ be a D2827: Measure-preserving system such that

(i) | $\mathcal{S} = \mathcal{Stat}(M)$ is the D2842: Set of stationary measurable sets in $M$ |

Then $\mathcal{S}$ is a D470: Subsigma-algebra of $\mathcal{F}$ on $X$.