On the Landau-Kolmogorov inequality between $$$\| f' \|_{\infty}$$$, $$$\| f \|_{\infty}$$$ and $$$\| f''' \|_1$$$

D. Skorokhodov (Oles Honchar Dnipro National University), http://orcid.org/0000-0001-8494-5885


We solve the Landau-Kolmogorov problem on finding sharp additive inequalities that estimate $$$\| f' \|_{\infty}$$$ in terms of $$$\| f \|_{\infty}$$$ and $$$\| f''' \|_1$$$. Simultaneously we solve related problems of the best approximation of first order differentiation operator $$$D^1$$$ by linear bounded ones and the best recovery of operator $$$D^1$$$ on elements of a class given with error.


the Landau-Kolmogorov problem; the Stechkin problem; best recovery of operator; modulus of continuity of operator

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DOI: https://dx.doi.org/10.15421/241906



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