共 50 条
On an analogue of a theorem by Astala and Tylli
被引:0
|作者:
Alexei Karlovich
Eugene Shargorodsky
机构:
[1] Universidade Nova de Lisboa,Centro de Matemática e Aplicações, Departamento de Matemática, Faculdade de Ciências e Tecnologia
[2] King’s College London,Department of Mathematics
[3] Technische Universität Dresden,Fakultät Mathematik
来源:
关键词:
Essential norm;
Measures of noncompactness;
Bounded compact approximation property;
Dual compact approximation property;
Primary 46B28;
Secondary 46B50;
47B07;
47H08;
D O I:
暂无
中图分类号:
学科分类号:
摘要:
Let ‖A‖e\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\Vert A\Vert _{\mathrm {e}}$$\end{document} be the essential norm of an operator A and ‖A‖m\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\Vert A\Vert _m$$\end{document} be the infimum of the norms of restrictions of A to the subspaces of finite codimension. We show that if ‖A‖e<M‖A‖m\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\Vert A\Vert _{\mathrm {e}}<M\Vert A\Vert _m$$\end{document} holds for every bounded noncompact operator A from a Banach space X to every Banach space Y, then the space X has the dual compact approximation property. This is an analogue of a result by Astala and Tylli (J Funct Anal 70(2):388–401, 1987) concerning the Hausdorff measure of noncompactness and the bounded compact approximation property.
引用
收藏
页码:73 / 77
页数:4
相关论文