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Y. A. Volynets

Publications and source records attributed to Y. A. Volynets.

2 recordsLinked to original sources

Numerical differentiation of functions on the half-line in a weighted uniform metric

We consider the problem of numerical differentiation of functions defined on the half-line: the derivative $f^{(r)}$, $ r=1,2,\ldots$, is recovered from a finite set of perturbed Fourier--Laguerre coefficients of a function $f$, whose error is measured in $\ell_p$, while the accuracy of approximation is measured in the uniform metric with the weight $t^αe^{-t}$. It is established that the Wiener class $W^μ_{s}$ admits such a setting for $μ>r+1-1/s$. A class of methods $\mathcal{S}^θ$ is constructed that realize the optimal order of accuracy of numerical differentiation on $W^μ_{s}$ and use the smallest amount of input information in order.

math.NA↗

Regularized summation of Fourier-Laguerre series in the weighted sup-norm

We consider the problem of recovering functions defined on the half-line from inexact input information. For the proposed regularizing summation methods based on Laguerre polynomials, we analyze their approximation properties on functions from Wiener classes. We establish conditions under which these methods are stable with respect to small perturbations of the input data and order-optimal not only in accuracy in the weighted $\sup$-norm, but also in the number of Fourier-Laguerre coefficients used.

math.NA↗