  The paper is pertaining to the spectral theory of operators and boundary
value problems for differential equations on manifolds. Eigenvalues of such
problems are studied as functionals on the space of domains. Resolvent
continuity of the corresponding operators is established under domain
deformation and estimates of continuity moduli of their eigenvalues $\slash$
eigenfunctions are obtained provided the boundary of nonperturbed domain is
locally represented as a graph of some continuous function and domain
deformation is measured with respect to the Hausdorff--Pompeiu metric.
