Weak forms of unconditionality of bases in greedy approximation
Volume 267 / 2022
Studia Mathematica 267 (2022), 1-17
MSC: Primary 41A65; Secondary 41A46, 41A17, 46B15, 46B45.
DOI: 10.4064/sm210601-2-2
Published online: 27 June 2022
Abstract
We study a new class of bases, weaker than quasi-greedy bases, which retain their unconditionality properties and can provide the same optimality for the thresholding greedy algorithm. We measure how far these bases are from being unconditional and use this concept to give a new characterization of nearly unconditional bases.
