High-dimensional sparse trigonometric approximation in the uniform norm and consequences for sampling recovery

Fuente: arXiv
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Auteurs principaux: Moeller, Moritz, Stasyuk, Serhii, Ullrich, Tino
Format: Preprint
Publié: 2024
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author Moeller, Moritz
Stasyuk, Serhii
Ullrich, Tino
author_facet Moeller, Moritz
Stasyuk, Serhii
Ullrich, Tino
contents Recent findings by Jahn, T. Ullrich, Voigtlaender [10] relate non-linear sampling numbers for the square norm to quantities involving trigonometric best $m-$term approximation errors in the uniform norm. Here we establish new results for sparse trigonometric approximation with respect to the high-dimensional setting, where the influence of the dimension $d$ has to be controlled. In particular, we focus on best $m-$term trigonometric approximation for (unweighted) Wiener classes in $L_q$ and give precise constants. Our main results are approximation guarantees where the number of terms $m$ scales at most quadratic in the inverse accuracy $1/\varepsilon$. Providing a refined version of the classical Nikol'skij inequality we are able to extrapolate the $L_q$-result to $L_\infty$ while limiting the influence of the dimension to a $\sqrt{d}$-factor and an additonal $\log$-term in the size of the (rectangular) spectrum. This has consequences for the tractable sampling recovery via $\ell_1$-minimization of functions belonging to certain Besov classes with bounded mixed smoothness. This complements polynomial tractability results recently given by Krieg [12].
format Preprint
id arxiv_https___arxiv_org_abs_2407_15965
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle High-dimensional sparse trigonometric approximation in the uniform norm and consequences for sampling recovery
Moeller, Moritz
Stasyuk, Serhii
Ullrich, Tino
Numerical Analysis
94A20, 41A46, 46E15, 42B35, 41A25, 65D15, 41A6
Recent findings by Jahn, T. Ullrich, Voigtlaender [10] relate non-linear sampling numbers for the square norm to quantities involving trigonometric best $m-$term approximation errors in the uniform norm. Here we establish new results for sparse trigonometric approximation with respect to the high-dimensional setting, where the influence of the dimension $d$ has to be controlled. In particular, we focus on best $m-$term trigonometric approximation for (unweighted) Wiener classes in $L_q$ and give precise constants. Our main results are approximation guarantees where the number of terms $m$ scales at most quadratic in the inverse accuracy $1/\varepsilon$. Providing a refined version of the classical Nikol'skij inequality we are able to extrapolate the $L_q$-result to $L_\infty$ while limiting the influence of the dimension to a $\sqrt{d}$-factor and an additonal $\log$-term in the size of the (rectangular) spectrum. This has consequences for the tractable sampling recovery via $\ell_1$-minimization of functions belonging to certain Besov classes with bounded mixed smoothness. This complements polynomial tractability results recently given by Krieg [12].
title High-dimensional sparse trigonometric approximation in the uniform norm and consequences for sampling recovery
topic Numerical Analysis
94A20, 41A46, 46E15, 42B35, 41A25, 65D15, 41A6
url https://arxiv.org/abs/2407.15965