On the singular numbers of correct restrictions of non-selfadjoint elliptic differential operators

Conditions are established on a correct restriction of an elliptic differential operator of order $2l$ defined on a bounded domain in $\mathbb R^n$ with sufficiently smooth boundary, ensuring that its singular numbers $s_k$ are of order $k^{-\frac{2l}n}$. As an application certain estimates are obtained for the deviation upon domain perturbation of singular numbers of such correct restrictions.