Magerovska T. Nonlocal boundary-value problems for hyperbolic equations and initial problem for typeless equations

In the dissertation the nonlocal problems with multipoint and integral conditions on marked variable and periodicity conditions on the rest coordinates for hyperbolic equations with variable coefficients, and also the initial problem for typeless equations and systems of equations with constant coefficients of the arbitrary order are considered. The conditions of existence of the unique solution of theses problems are established. The solutions of theses problems are constructed in the form of Fourier series. The new metric theorems about estimates from below of small denominators, that appear in construction of solutions of the problems, are proved.