Approximation properties of de la Vallée Poussin means of partial Fourier series in Meixner–Sobolev polynomials

We study approximations of a function $f\in W^r_{l^2_{\omega}(\Omega_\delta)}$, $\omega(x)=e^{-x}(1-e^{-\delta})$, by the de la Vallée Poussin means of partial sums of the Fourier series in the Sobolev orthonormal system of polynomials $\{m_{n,N}^{0,r}(x)\}$ generated by the system of Meixner polynomials.
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