Partial Differential Equations


Smoothness of solutions of a problem with an oblique derivative K. I. Bazyk

3 

On the Cauchy problem for harmonic functions A. V. Bitsadze

11 

A fourthorder evolution equation encountered in underwater acoustics of a stratified fluid S. A. Gabov, B. B. Orazov, A. G. Sveshnikov

19 

Boundary value problems for a class of fourthorder equations of mixed type T. D. Dzhuraev, M. Mamazhanov

25 

Stabilization of means with respect to time of the solution of the Cauchy problem for a singular hyperbolic equation V. N. Denisov

31 

Fundamental mixed boundary value problem for elliptic systems in the plane N. A. Zhura

44 

The Bitsadze–Samarskiǐ problem for equations of mixed type M. M. Zainulabidov

54 

Solvability in the class $L_2$ of the Tricomi problem for a parabolichyperbolic equation with a degenerate hyperbolic part N. Yu. Kapustin

60 

Boundary value problems for equations of mixed type containing a mixed derivative A. G. Kuz'min

66 

The behavior of eigen and associated functions of the Schrödinger operator at the point of discontinuity of the potential N. M. Mahmedzhanov, V. V. Tikhomirov

74 

An inequality connected with the solution of a differential equation E. I. Moiseev

82 

The property of being an unconditional basis on a closed interval of systems of eigen and associated functions of a quadratic pencil of nonselfadjoint differential operators M. Rakhimov

94 

A problem with a normal derivative for an equation of mixed type with nonsmooth lines of degeneracy M. S. Salakhitdinov, Z. Kadyrov

103 

Estimation of spectral density corresponding to an expansion in an $N$multiple system of exponentials Ya. Sh. Salimov

114 

Uniform equiconvergence of expansions in a system of exponentials with associated functions, and trigonometric Fourier series T. A. Samarskaya

125 

Fractional powers of a differential operator with singularity V. S. Serov

134 

Asymptotic behavior of solutions of singular integral equations A. P. Soldatov

143 

Characteristic problem for a class of secondorder hyperbolic systems with parabolic degeneration S. S. Kharibegashvili

153 

Short Communications


An analogue of the Tricomi–Neumann problem for an equation of parabolichyperbolic type S. Dauenov

165 

The basis property of a trigonometric system of functions G. G. Devdariani

168 

The basis property of a system of functions G. G. Devdariani

170 

A nonlocal problem for partial differential equations Z. A. Nakhusheva

171 

Approximate solution of twodimensional Abel type integral equations Teng Meng Yan

175 

A problem of Riemann–Hilbert type for a degenerate elliptic system of firstorder equations Kh. R. Shukurov

176 