Abstract:
We give an upper bound for the error of the best approximation of the (first-order) differentiation operator by linear bounded operators on the class of twice differentiable functions in the space L2(0,∞). This upper bound is close to a known lower bound and improves the previous upper bounds. To prove the upper estimate, we consider a specific family of operators; in this family, we choose an operator that provides the least bound for the error of the best approximation.
Citation:
V. V. Arestov, M. A. Filatova, “On the approximation of the differentiation operator by linear bounded operators on the class of twice differentiable functions in the space L2(0,∞)”, Trudy Inst. Mat. i Mekh. UrO RAN, 18, no. 4, 2012, 35–50; Proc. Steklov Inst. Math. (Suppl.), 284, suppl. 1 (2014), 24–40
\Bibitem{AreFil12}
\by V.~V.~Arestov, M.~A.~Filatova
\paper On the approximation of the differentiation operator by linear bounded operators on the class of twice differentiable functions in the space $L_2(0,\infty)$
\serial Trudy Inst. Mat. i Mekh. UrO RAN
\yr 2012
\vol 18
\issue 4
\pages 35--50
\mathnet{http://mi.mathnet.ru/timm865}
\elib{https://elibrary.ru/item.asp?id=18126466}
\transl
\jour Proc. Steklov Inst. Math. (Suppl.)
\yr 2014
\vol 284
\issue , suppl. 1
\pages 24--40
\crossref{https://doi.org/10.1134/S0081543814020035}
\isi{https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=Publons&SrcAuth=Publons_CEL&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=000334277400003}
\scopus{https://www.scopus.com/record/display.url?origin=inward&eid=2-s2.0-84898717408}
Linking options:
https://www.mathnet.ru/eng/timm865
https://www.mathnet.ru/eng/timm/v18/i4/p35
This publication is cited in the following 2 articles:
Arestov V., Filatova M., “Best Approximation of the Differentiation Operator in the Space l-2 on the Semiaxis”, J. Approx. Theory, 187 (2014), 65–81
Arestov V.V., Filatova M.A., “the Best Approximation of the Differentiation Operator By Linear Bounded Operators in the Space l (2) on the Semiaxis”, Dokl. Math., 90:2 (2014), 592–595