Semitopological group;
T-i-refiection;
Open homomorphism;
Feebly compact;
D O I:
10.1016/j.topol.2014.12.020
中图分类号:
O29 [应用数学];
学科分类号:
070104 ;
摘要:
Given a semitopological group G, denote by N(e) the family of open neighborhoods of the identity e in G. We show that K = boolean AND{(U) over bar : U is an element of N(e)} is a closed invariant subgroup of G. Therefore, the T-2-reflection of G is topologically isomorphic to G/K. Also, we show that in every semitopological group G, the following conditions are equivalent: i) G is feebly compact; ii) T-0(G) is feebly compact; iii) T-1(G) is feebly compact; iv) T-2(G) is feebly compact. These results answer some questions posed by M. Tkachenko about the T-i-reflection of semitopological groups, for i = 1, 2. (C) 2014 Elsevier B.V. All rights reserved.
机构:
Univ Autonoma Metropolitana, Dept Matemat, Av San Rafael Atlixco 186, Mexico City 09340, MexicoUniv Autonoma Metropolitana, Dept Matemat, Av San Rafael Atlixco 186, Mexico City 09340, Mexico
机构:
Beijing Univ Technol, Sch Math Stat & Mech, Dept Math, Beijing 100124, Peoples R ChinaBeijing Univ Technol, Sch Math Stat & Mech, Dept Math, Beijing 100124, Peoples R China
Peng, Liang-Xue
Deng, Yu-Ming
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h-index: 0
机构:
Beijing Univ Technol, Sch Math Stat & Mech, Dept Math, Beijing 100124, Peoples R ChinaBeijing Univ Technol, Sch Math Stat & Mech, Dept Math, Beijing 100124, Peoples R China
机构:
Northeastern Univ Qinhuangdao, Sch Math & Stat, Qinhuangdao 066004, Hebei, Peoples R ChinaNortheastern Univ Qinhuangdao, Sch Math & Stat, Qinhuangdao 066004, Hebei, Peoples R China
Li, Piyu
Mou, Lei
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h-index: 0
机构:
Capital Normal Univ, Sch Math Sci, Beijing 100048, Peoples R ChinaNortheastern Univ Qinhuangdao, Sch Math & Stat, Qinhuangdao 066004, Hebei, Peoples R China
Mou, Lei
Wang, Hanfeng
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h-index: 0
机构:
Shandong Agr Univ, Dept Math, Tai An 271018, Shandong, Peoples R ChinaNortheastern Univ Qinhuangdao, Sch Math & Stat, Qinhuangdao 066004, Hebei, Peoples R China
Wang, Hanfeng
Xie, Li-Hong
论文数: 0引用数: 0
h-index: 0
机构:
Wuyi Univ, Sch Math & Computat Sci, Jiangmen 529020, Peoples R ChinaNortheastern Univ Qinhuangdao, Sch Math & Stat, Qinhuangdao 066004, Hebei, Peoples R China
机构:
Univ Autonoma Metropolitana, Dept Matemat, Del Iztapalapa 09340, DF, MexicoUniv Autonoma Metropolitana, Dept Matemat, Del Iztapalapa 09340, DF, Mexico