We determine the exact values of the upper bounds of n-term approximations of q-ellipsoids by Λ-methods in the spaces Sϕq in the metrics of the spaces Sϕp.

We investigate approximations of analytic functions determined by Cauchy-type integrals in Jordan domains of the complex plane. We develop, modify, and complete (in a certain sense) our earlier… Expand

We present a survey of new results related to the investigation of the rate of convergence of Fourier sums on the classes of functions defined by convolutions whose kernels have monotone Fourier… Expand

AbstractWe study the set $$
\mathcal{D}^\infty
$$ of infinitely differentiable periodic functions in terms of generalized $$
\bar \psi
$$-derivatives defined by a pair $$
\bar \psi = (\psi _1 ,\psi… Expand

The approximation properties of the spaces Sϕp introduced by Stepanets’ were studied in a series of works of Stepanets’ and his disciples. In these works, problems related to the determination of… Expand

AbstractWe find asymptotic formulas for the least upper bounds of the deviations of Fourier operators on classes of functions locally summable on the entire real axis and defined by
$$
\bar \Psi… Expand