Let $U \subset \mathbb{R}^n$ be open. Let $A \in \Psi^m(U)$ be a pseudodifferential operator of order $m < 0$, and let $\chi,\psi \in C_c^\infty(U)$ satisfy $\psi = 1$ on an open neighbourhood of $\operatorname{supp}\chi$. For every $s \in \mathbb{R}$, the operator