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This article is cited in 6 scientific papers (total in 6 papers)
Free interpolation in the spaces $ C^A_{r,\omega}$
N. A. Shirokov
Abstract:
Let the integer $r\geqslant0$ and the modulus of continuity $\omega(t)$ be fixed, and let $C^A_{r,\omega}$ be the class of all functions continuous on the closed unit disk $\overline D$, analytic on its interior $D$, and having an $\omega$-continuous $r$th derivative on $\overline D$.
Consider for each $f\in C^A_{r,\omega}$ and each fixed $\zeta\in\overline D$ the polynomial in $z$
$$
P_{r,\zeta}(z;f)=\sum_{\nu=0}^r \dfrac{f^{(\nu)}(\zeta)}{\nu!}
$$
(the $(r+1)$st partial sum of the Taylor series of $f$ in a neighborhood of $\zeta$). Then for any two points $\zeta_1,\zeta_2\in\overline D$
\begin{equation}
\begin{gathered}
|(P_{r,\zeta_1}(z)-P_{r,\zeta_2}(z))^{(\nu)}|_{z=\zeta_1}\leqslant c_f|\zeta_1-\zeta_2|^{r-\nu}\omega(|\zeta_1-\zeta_2|),
\\
P_{\,\cdot\,,\,\cdot\,}(\,\cdot\,)=P_{\,\cdot\,,\,\cdot\,}(\,\cdot\,;f),\qquad 0\leqslant\nu\leqslant r.
\end{gathered}
\tag{1.1}
\end{equation}
Let $E$ be a closed subset of $\overline D$. This article contains a solution of the problem of free interpolation in $C^A_{r,\omega}$, formulated as follows: find necessary and sufficient conditions on $E$ such that for each collection $\{P_\zeta\}_{\zeta\in E}$ of $r$th-degree polynomials satisfying conditions of the type (1.1) for all $\zeta_1,\zeta_2\in E$ there is a function $f\in C^A_{r,\omega}$ with $P_\zeta(\,\cdot\,)=P_{r,\zeta}(\,\cdot\,;f)$.
Bibliography: 13 titles.
Received: 10.02.1981
Citation:
N. A. Shirokov, “Free interpolation in the spaces $ C^A_{r,\omega}$”, Math. USSR-Sb., 45:3 (1983), 337–358
Linking options:
https://www.mathnet.ru/eng/sm2212https://doi.org/10.1070/SM1983v045n03ABEH001011 https://www.mathnet.ru/eng/sm/v159/i3/p337
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Abstract page: | 329 | Russian version PDF: | 88 | English version PDF: | 13 | References: | 52 |
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