Source: wikibot/cotlar-stein-lemma
= Cotlar–Stein lemma
{wiki=Cotlar–Stein_lemma}
The Cotlar–Stein lemma is a result in functional analysis, particularly in the theory of bounded operators on Hilbert spaces. It provides a criterion under which a certain type of operator can be shown to be compact. While the lemma itself can be quite specialized, its essence can be articulated as follows: Suppose \\(T\\) is a bounded linear operator on a Hilbert space \\(H\\).