Negative Sobolev regularity of a compactly supported distribution
= Negative Sobolev regularity of a compactly supported distribution
{title2=$u\in H^s,\ s<-M-n/2$}
A <compactly supported distribution> of <order of a distribution> at most $M$ has a <smooth function> as its <Fourier transform>, bounded by $C\langle\xi\rangle^M$. It therefore belongs to every <Sobolev space> $H^s$ with $s<-M-n/2$.