Extremal properties of the set of vector-valued Banach limits

In this manuscript we find another class of real Banach spaces which admit vector-valued Banach limits different from the classes found in [6, 7]. We also characterize the separating subsets of ℓ∞(X). For this we first need to study when the space of almost convergent sequences is closed in the spac...

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Main Author: García-Pacheco Francisco Javier
Format: Article
Language:English
Published: De Gruyter 2015-11-01
Series:Open Mathematics
Subjects:
Online Access:https://doi.org/10.1515/math-2015-0067
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spelling doaj-ca18d359a34a4e3bb67130330eb0458d2021-09-06T19:20:07ZengDe GruyterOpen Mathematics2391-54552015-11-0113110.1515/math-2015-0067math-2015-0067Extremal properties of the set of vector-valued Banach limitsGarcía-Pacheco Francisco Javier0Department of Mathematics, University of Cadiz, Puerto Real 11510, SpainIn this manuscript we find another class of real Banach spaces which admit vector-valued Banach limits different from the classes found in [6, 7]. We also characterize the separating subsets of ℓ∞(X). For this we first need to study when the space of almost convergent sequences is closed in the space of bounded sequences, which turns out to happen only when the underlying space is complete. Finally, a study on the extremal structure of the set of vector-valued Banach limits is conducted when the underlying normed space is a Hilbert space.We also reach the conclusion that the set of vector-valued Banach limits is not a convex component of BCL(ℓ∞(X),X), provided that X is a 1-injective Banach space satisfying that the underlying compact Hausdorff topological space has isolated points.https://doi.org/10.1515/math-2015-0067banach limit almost convergence group of isometries extremal structure
collection DOAJ
language English
format Article
sources DOAJ
author García-Pacheco Francisco Javier
spellingShingle García-Pacheco Francisco Javier
Extremal properties of the set of vector-valued Banach limits
Open Mathematics
banach limit
almost convergence
group of isometries
extremal structure
author_facet García-Pacheco Francisco Javier
author_sort García-Pacheco Francisco Javier
title Extremal properties of the set of vector-valued Banach limits
title_short Extremal properties of the set of vector-valued Banach limits
title_full Extremal properties of the set of vector-valued Banach limits
title_fullStr Extremal properties of the set of vector-valued Banach limits
title_full_unstemmed Extremal properties of the set of vector-valued Banach limits
title_sort extremal properties of the set of vector-valued banach limits
publisher De Gruyter
series Open Mathematics
issn 2391-5455
publishDate 2015-11-01
description In this manuscript we find another class of real Banach spaces which admit vector-valued Banach limits different from the classes found in [6, 7]. We also characterize the separating subsets of ℓ∞(X). For this we first need to study when the space of almost convergent sequences is closed in the space of bounded sequences, which turns out to happen only when the underlying space is complete. Finally, a study on the extremal structure of the set of vector-valued Banach limits is conducted when the underlying normed space is a Hilbert space.We also reach the conclusion that the set of vector-valued Banach limits is not a convex component of BCL(ℓ∞(X),X), provided that X is a 1-injective Banach space satisfying that the underlying compact Hausdorff topological space has isolated points.
topic banach limit
almost convergence
group of isometries
extremal structure
url https://doi.org/10.1515/math-2015-0067
work_keys_str_mv AT garciapachecofranciscojavier extremalpropertiesofthesetofvectorvaluedbanachlimits
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