Shchogolev S. The some problems of the theory of oscillations for the differential sysytems, containing slowly varying parameters

The thesis is devoted to the research of the quasilinear systems of the differential equations, whose coefficients are represented as an absolutely and uniformly convergent Fourier-series with slowly varying coefficients and frequencies. The conditions of existence of particular solutions of the similar structure are obtained at the various assumtions about properties of matrix of linear part of these systems. Based on these results the conditions of the possibility of complete separation of the homogeneous linear system of differential equations whose coefficients are represented as an absolutely and uniformly convergent Fourier-series with slowly varying coefficients and frequencies, are obtained.