Ordinary Differential Equations


On a scheme for studying cycles of nonlinear systems N. A. Bobylev, A. V. Bulatov, S. K. Korovin, A. A. Kutuzov

3 

Some properties of root functions of differential operators that are connected with the unconditional basis property V. D. Budaev

9 

The curve of separatrix cycles of an autonomous quadratic system in the plane. The case of two antisaddles S. I. Dovnar, L. A. Cherkas

15 

Some estimates for root functions of a matrix differential operator with a diagonalmatrix eigenvalue A. V. Dyadechko

22 

An estimate, uniform on the whole line $\mathbb R$, for the rate of convergence of a spectral expansion corresponding to the Schrödinger operator with a summable potential V. A. Il'in, L. V. Kritskov

32 

On necessary and sufficient conditions for the basis property of systems of root functions of a differential operator N. B. Kerimov

37 

The potential method in a linear timeoptimality problem Yu. N. Kiselev, M. V. Orlov

44 

Singular Cauchy problems for singularly perturbed systems of nonlinear ordinary differential equations. I N. B. Konyukhova

52 

Distribution of eigenvalues for uniformly minimal systems of root functions of ordinary differential operators L. V. Kritskov

62 

On the rate of convergence of biorthogonal series connected with secondorder differential operators I. S. Lomov

71 

Partial Differential Equations


On the convergence of Riesz means of spectral expansions that correspond to the Schrödinger operator with a singular potential N. S. Buzurnyuk, V. S. Serov

83 

The generalized Fourier method for solving mixed problems for nonlinear equations A. I. Vagabov

90 

On the semidiscretization method in the problem of periodic solutions of quasilinear autonomous parabolic equations I. N. Gurova, M. I. Kamenskii

101 

On some problem of the reconstruction of a boundary condition for a parabolic equation. I A. B. Kostin, A. I. Prilepko

107 

On the differential properties of expansions in a system of sines and cosines E. I. Moiseev

117 

Short Communications


On the construction of solutions of linear difference systems with continuous time M. G. Blizorukov

127 

On a method for solving a form of integral equations of the first kind A. N. Zarubin

129 

On solutions, bounded on the halfaxis, of nonlinear differential equations V. N. Laptinskii

131 

On a boundary value problem for the Schrödinger operator with a complex potential A. S. Makin

133 

On the expansion of the solution of the generalized Gellerstedt problem in a biorthogonal series A. A. Polosin

135 

On a connection between the solutions of a linear differential equation and solutions of a conjugate equation A. K. Svinin

138 