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This article is cited in 2 scientific papers (total in 2 papers)
Real, complex and functional analysis
Best approximation of differentiation operators on the Sobolev class of functions analytic in a strip
R. R. Akopyan N.N. Krasovskii Institute of Mathematics and Mechanics, 16, S. Kovalevskaya str., Yekaterinburg, 620100, Russia
Abstract:
A solution is obtained for interconnected extremal problems on the class of analytic functions in a strip with finite $L^2$-norms of limit values of functions on one boundary line and bounded $L^2$-norms of limit values of the derivative of order $n, n\ge 0,$ on the other boundary line: best approximation of the differentiation operators with respect to the uniform norm on an intermediate line by bounded operators; optimal recovery of the derivative of order k on an intermediate line from values of the function on the boundary line given with an error. An exact Kolmogorov-type inequality is obtained that estimates the uniform norm of the derivative of order $k$ on an intermediate line in terms of the $L^2$-norm of the limit boundary values of the function and the derivative of order $n.$
Keywords:
analytic functions, best approximation of the operator, optimal recovery, Kolmogorov inequality.
Received October 25, 2021, published November 19, 2021
Citation:
R. R. Akopyan, “Best approximation of differentiation operators on the Sobolev class of functions analytic in a strip”, Sib. Èlektron. Mat. Izv., 18:2 (2021), 1286–1298
Linking options:
https://www.mathnet.ru/eng/semr1439 https://www.mathnet.ru/eng/semr/v18/i2/p1286
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Abstract page: | 122 | Full-text PDF : | 40 | References: | 16 |
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