Krein’s Theorem in the Context of Topological Abelian Groups

A topological abelian group <i>G</i> is said to have the quasi-convex compactness property (briefly, qcp) if the quasi-convex hull of every compact subset of <i>G</i> is again compact. In this paper we prove that there exist locally quasi-convex metrizable complete groups <...

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Bibliographic Details
Main Authors: Tayomara Borsich, Xabier Domínguez, Elena Martín-Peinador
Format: Article
Language:English
Published: MDPI AG 2022-05-01
Series:Axioms
Subjects:
Online Access:https://www.mdpi.com/2075-1680/11/5/224
Description
Summary:A topological abelian group <i>G</i> is said to have the quasi-convex compactness property (briefly, qcp) if the quasi-convex hull of every compact subset of <i>G</i> is again compact. In this paper we prove that there exist locally quasi-convex metrizable complete groups <i>G</i> which endowed with the weak topology associated to their character groups <inline-formula><math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><msup><mi>G</mi><mo>∧</mo></msup></semantics></math></inline-formula>, do not have the qcp. Thus, Krein’s Theorem, a well known result in the framework of locally convex spaces, cannot be fully extended to locally quasi-convex groups. Some features of the qcp are also studied.
ISSN:2075-1680