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Real-Analytic Negligibility of Points and Subspaces in Banach Spaces, with Applications

Published online by Cambridge University Press:  20 November 2018

D. Azagra
Affiliation:
Departamento de Análisis Matemático, Facultad de Ciencias Matemáticas, Universidad Complutense, Madrid 28040, Spain, email: daniel@sunam1.mat.ucm.es
T. Dobrowolski
Affiliation:
Department of Mathematics, Pittsburg State University, Pittsburg, Kansas 66762, USA, email: tdobrowo@mail.pittstate.edu
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Abstract

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We prove that every infinite-dimensional Banach space $X$ having a (not necessarily equivalent) real-analytic norm is real-analytic diffeomorphic to $X\,\backslash \,\left\{ 0 \right\}$. More generally, if $X$ is an infinite dimensional Banach space and $F$ is a closed subspace of $X$ such that there is a real-analytic seminorm on $X$ whose set of zeros is $F$, and $X/F$ is infinite-dimensional, then $X$ and $X\backslash F$ are real-analytic diffeomorphic. As an application we show the existence of real-analytic free actions of the circle and the $n$-torus on certain Banach spaces.

Keywords

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2002

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