We consider singular perturbed eigenvalue problem for Laplace operator in a
cylinder with frequent and nonperiodic alternation of boundary conditions
imposed on narrow strips lying in the lateral surface. The width of strips
depends on a small parameter in a arbitrary way and may oscillate fast,
moreover, the nature of oscillation is arbitrary, too. We obtain two-sided
estimates for degree of convergences of the perturbed eigenvalues.Comment: This preprint is a short version; the bigger version with more
results will appear in "Computational Mathematics and Mathematical Physics