On some kinds of ω-balancedness in semitopological groups

被引:8
作者
Peng, Liang-Xue [1 ]
Zhang, Pei [1 ]
机构
[1] Beijing Univ Technol, Coll Appl Sci, Beijing 100124, Peoples R China
基金
北京市自然科学基金; 中国国家自然科学基金;
关键词
Semitopological group; Paratopological group; omega-balanced; Moore space; Point-countable base; PRODUCTS; SUBGROUPS; SPACES;
D O I
10.1016/j.topol.2020.107128
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
In this article, we introduce two notions which are called M-omega-balancedness and C-omega-balancedness, respectively. We get the following conclusions. A regular semitopological group G is topologically isomorphic to a subgroup of the product of a family of Moore semitopological groups if and only if G is M-omega-balanced and Ir(G) <= omega. A T(1 )semitopological group G is topologically isomorphic to a subgroup of the product of a family of T-1 semitopological groups with a point-countable base if and only if G is C-w-balanced and Sm(G) <= omega. If G is a Hausdorff countably compact semitopological group with Hs(G) <= omega, then the M-omega-balancedness (C-omega-balancedness) of G implies that G is a topological group. Let G be an omega-balanced paratopological group and let e be the identity of G. We show that if for each U is an element of N(e) there exist omega-good set V is an element of N(e) with V subset of U and A subset of G such that boolean OR{g(V boolean AND V-1) : g is an element of A} = G and {g(V boolean AND V-1)V : g is an element of A} is star-countable, then G is completely omega-balanced, where N(e) is the family of open neighborhoods of e in G. (C) 2020 Elsevier B.V. All rights reserved.
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页数:17
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