Greedy approximation for biorthogonal systems in quasi-Banach spaces

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Date
2021Version
Acceso abierto / Sarbide irekia
Type
Artículo / Artikulua
Version
Versión aceptada / Onetsi den bertsioa
Project Identifier
AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2019-105599GB-I00/ES/
ES/1PE/MTM2016-76566-P AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PGC2018-095366-B-I00/ES/
AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2019-107701GB-I00/ES/
Impact
|
10.4064/dm817-11-2020
Abstract
The general problem addressed in this work is the development of a systematic study of the thresholding greedy algorithm for general biorthogonal systems in quasi-Banach spaces from a functional-analytic point of view. If (Formula Presented) is a biorthogonal system in X then for each x ∈ X we have a formal expansion (Formula Presented). The thresholding greedy algorithm (with threshold ε > 0) ap ...
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The general problem addressed in this work is the development of a systematic study of the thresholding greedy algorithm for general biorthogonal systems in quasi-Banach spaces from a functional-analytic point of view. If (Formula Presented) is a biorthogonal system in X then for each x ∈ X we have a formal expansion (Formula Presented). The thresholding greedy algorithm (with threshold ε > 0) applied to x is formally defined as (Formula Presented). The properties of this operator give rise to the different classes of greedy-type bases. We revisit the concepts of greedy, quasi-greedy, and almost greedy bases in this comprehensive framework and provide the (non-trivial) extensions of the corresponding characterizations of those types of bases. As a by-product of our work, new properties arise, and the relations among them are carefully discussed. [--]
Subject
Almost greedy,
Democratic basis,
Greedy basis,
Quasi-Banach spaces,
Quasi-greedy basis,
Unconditional basis
Publisher
Instytut Matematyczny
Published in
Dissertationes Mathematicae, 560, (2021), 1-88
Departament
Universidad Pública de Navarra. Departamento de Estadística, Informática y Matemáticas /
Nafarroako Unibertsitate Publikoa. Estatistika, Informatika eta Matematika Saila /
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. Institute for Advanced Materials and Mathematics - INAMAT2
Publisher version
Sponsorship
F. Albiac acknowledges the support of the Spanish Ministry for Science and Innovation under Grant PID2019-107701GB-I00 for Operators, lattices, and structure of Banach spaces. F. Albiac and J. L. Ansorena acknowledge the support of the Spanish Ministry for Science, Innovation, and Universities Grant PGC2018-095366-B-I00 for Análisis Vectorial, Multilineal y Aplicaciones. P. M. Berná acknowledges the support of the Spanish Ministry for Economy and Competitivity Grants MTM-2016-76566-P and PID2019-105599GB-100 (Agencia Estatal de Investigación). P. M. Berná was also supported by Grant 20906/PI/18 from Fundación Séneca (Región de Murcia, Spain). P. Wojtaszczyk was partially supported by National Science Centre, Poland, grant UMO-2016/21/B/ST1/00241. This work was supported by EPSRC grant number EP/R014604/1.