St. Petersburg Mathematical Journal, 16. cilt

analytic apply approximation assume asymptotic belongs BKN-equation block boundary bounded called closed coefficients collection compatible complete components condition Consequently consider constant construction contains continuous corresponding covering defined definition denote differential domain edge eigenvalues embedding English equal equation estimate example exists extension fact fibers field finite fixed formula function given graph harmonic identity implies inequality integral introduce invertible Lemma linear manifold Math Mathematical matrix monodromy Moreover norm obtain operator oriented pair particular periodic polynomial positive potential present problem proof properties Proposition prove rational relation Remark representation respect result satisfies selfadjoint separation singular smooth solution space spectral spectrum statement Subsection sufficiently Suppose surface symmetric Theorem theory transformation transl true unique values vector vertex vertices zero