The topological structure of (homogeneous) spaces and groups with countable cs∗-character

In this paper we introduce and study three new cardinal topological invariants called the cs∗-, cs-, and sb-characters. The class of topological spaces with countable cs∗-character is closed under many topological operations and contains all N-spaces and all spaces with point-countable cs∗-network....

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Main Authors: Taras Banak, Lubomyr Zdomskyi
Format: Article
Language:English
Published: Universitat Politècnica de València 2004-04-01
Series:Applied General Topology
Subjects:
Online Access:http://polipapers.upv.es/index.php/AGT/article/view/1993
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spelling doaj-7ee96f7213a14cffa41fdfdbbe4d351e2020-11-24T22:17:45ZengUniversitat Politècnica de ValènciaApplied General Topology1576-94021989-41472004-04-0151254810.4995/agt.2004.19931615The topological structure of (homogeneous) spaces and groups with countable cs∗-characterTaras Banak0Lubomyr Zdomskyi1Akademia SwietorzyskaIvan Franko Lviv National UniversityIn this paper we introduce and study three new cardinal topological invariants called the cs∗-, cs-, and sb-characters. The class of topological spaces with countable cs∗-character is closed under many topological operations and contains all N-spaces and all spaces with point-countable cs∗-network. Our principal result states that each non-metrizable sequential topological group with countable cs∗- character has countable pseudo-character and contains an open kω- subgroup. This result is specific for topological groups: under Martin Axiom there exists a sequential topologically homogeneous kω-space X with N0 = cs∗x ­(X) <ψ (X).http://polipapers.upv.es/index.php/AGT/article/view/1993sb-networkcs-networ, cs∗-networkSequential topological groupkω-groupTopologically homogeneous spaceSmall cardinalCardinal invariant
collection DOAJ
language English
format Article
sources DOAJ
author Taras Banak
Lubomyr Zdomskyi
spellingShingle Taras Banak
Lubomyr Zdomskyi
The topological structure of (homogeneous) spaces and groups with countable cs∗-character
Applied General Topology
sb-network
cs-networ
, cs∗-network
Sequential topological group
kω-group
Topologically homogeneous space
Small cardinal
Cardinal invariant
author_facet Taras Banak
Lubomyr Zdomskyi
author_sort Taras Banak
title The topological structure of (homogeneous) spaces and groups with countable cs∗-character
title_short The topological structure of (homogeneous) spaces and groups with countable cs∗-character
title_full The topological structure of (homogeneous) spaces and groups with countable cs∗-character
title_fullStr The topological structure of (homogeneous) spaces and groups with countable cs∗-character
title_full_unstemmed The topological structure of (homogeneous) spaces and groups with countable cs∗-character
title_sort topological structure of (homogeneous) spaces and groups with countable cs∗-character
publisher Universitat Politècnica de València
series Applied General Topology
issn 1576-9402
1989-4147
publishDate 2004-04-01
description In this paper we introduce and study three new cardinal topological invariants called the cs∗-, cs-, and sb-characters. The class of topological spaces with countable cs∗-character is closed under many topological operations and contains all N-spaces and all spaces with point-countable cs∗-network. Our principal result states that each non-metrizable sequential topological group with countable cs∗- character has countable pseudo-character and contains an open kω- subgroup. This result is specific for topological groups: under Martin Axiom there exists a sequential topologically homogeneous kω-space X with N0 = cs∗x ­(X) <ψ (X).
topic sb-network
cs-networ
, cs∗-network
Sequential topological group
kω-group
Topologically homogeneous space
Small cardinal
Cardinal invariant
url http://polipapers.upv.es/index.php/AGT/article/view/1993
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AT lubomyrzdomskyi thetopologicalstructureofhomogeneousspacesandgroupswithcountablecscharacter
AT tarasbanak topologicalstructureofhomogeneousspacesandgroupswithcountablecscharacter
AT lubomyrzdomskyi topologicalstructureofhomogeneousspacesandgroupswithcountablecscharacter
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