Building highly conditional almost greedy and quasi-greedy bases in Banach spaces
Abstract
It is known that for a conditional quasi-greedy basis in a Banach space , the associated sequence of its conditionality constants verifies the estimate and that if the reverse inequality holds then is non-superreflexive. Indeed, it is known that a quasi-greedy basis in a superreflexive quasi-Banach space fulfils the estimate for some . However, in the existing literature one finds very few instances of spaces possessing quasi-greedy basis with conditionality constants "as large as possible." Our goal in this article is to fill this gap. To that end we enhance and exploit a technique developed in [S. J. Dilworth, N. J. Kalton, and D. Kutzarova, On the existence of almost greedy bases in Banach spaces, Studia Math. 159 (2003), no. 1, 67-101] and craft a wealth of new examples of both non-superreflexive classical Banach spaces having quasi-greedy bases with and superreflexive classical Banach spaces having for every quasi-greedy bases with . Moreover, in most cases those bases will be almost greedy.
Keywords
Cite
@article{arxiv.1803.08351,
title = {Building highly conditional almost greedy and quasi-greedy bases in Banach spaces},
author = {Fernando Albiac and Jose L. Ansorena and Stephen Dilworth and Denka Kutzarova},
journal= {arXiv preprint arXiv:1803.08351},
year = {2018}
}
Comments
arXiv admin note: text overlap with arXiv:1712.04004