2017
Том 69
№ 9

### All Issues

Articles: 2
Brief Communications (Ukrainian)

### On the Lebesgue Inequality on Classes of $\bar{\psi}$ -Differentiable Functions

Ukr. Mat. Zh. - 2013. - 65, № 6. - pp. 844–849

We consider the deviations of Fourier sums in the spaces ${C^{\bar{\psi}}}$. The estimates of these deviations are expressed via the best approximations of the $\bar{\psi}$ -derivatives of functions in the Stepanets sense. The sequences $\bar{\psi} = (ψ_1, ψ_2)$ are quasiconvex.

Article (Ukrainian)

### Approximation by Fourier sums of classes of periodic functions of several variables defined by polyharmonic operators

Ukr. Mat. Zh. - 1980. - 32, № 2. - pp. 212 - 219