The best polynomial approximation, derivatives of fractional order, and widths of classes of functions in $L_2$
Keyword(s):
On the classes of $2\pi$-periodic functions ${\mathcal{W}}^{\alpha} (K_{\beta}, \Phi)$, where $\alpha, \beta \in (0;\infty)$, defined by $K$-functionals $K_{\beta}$, fractional derivatives of order $\alpha$, and majorants $\Phi$, the exact values of different $n$-widths have been computed in the space $L_2$.
2015 ◽
Vol 27
(1)
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pp. 1-16
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2020 ◽
Vol 13
(02)
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pp. 2050011
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2020 ◽
Vol 20
(13)
◽
pp. 2041011