Almost Auerbach, Markushevich and Schauder bases in Hilbert and Banach spaces

IF 1.7 2区 数学 Q1 MATHEMATICS
Anton Tselishchev
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Abstract

For any sequence of positive numbers (εn)n=1 such that n=1εn= we provide an explicit simple construction of (1+εn)-bounded Markushevich basis in a separable Hilbert space which is not strong, or, in other terminology, is not hereditary complete; this condition on the sequence (εn)n=1 is sharp. Using a finite-dimensional version of this construction, Dvoretzky's theorem and a construction of Vershynin, we conclude that in any Banach space for any sequence of positive numbers (εn)n=1 such that n=1εn2= there exists a (1+εn)-bounded Markushevich basis which is not a Schauder basis after any permutation of its elements.
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来源期刊
CiteScore
3.20
自引率
5.90%
发文量
271
审稿时长
7.5 months
期刊介绍: The Journal of Functional Analysis presents original research papers in all scientific disciplines in which modern functional analysis plays a basic role. Articles by scientists in a variety of interdisciplinary areas are published. Research Areas Include: • Significant applications of functional analysis, including those to other areas of mathematics • New developments in functional analysis • Contributions to important problems in and challenges to functional analysis
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