We prove that a topological group G is strongly countably complete (the notion introduced by Z. Frolik in 1961) iff G contains a closed countably compact subgroup H such that the quotient space G/H is completely metrizable and the canonical mapping pi : G -> G/H is closed. We also show that every strongly countably complete group is sequentially complete, has countable G(delta)-tightness, and its completion is a tech-complete topological group. Further, a pseudocompact strongly countably complete group is countably compact. An example of a pseudocompact topological Abelian group H with the Frechet-Urysohn property is presented such that H fails to be sequentially complete, thus answering a question posed by Dikranjan, Martin Peinador, and Tarieladze in [Appl. Categor. Struct. 15 (2007) 511-539]. (C) 2012 Elsevier B.V. All rights reserved.
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Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA
UC Santa Barbara, Dept Math, Santa Barbara, CA 93106 USAUniv Calif Santa Barbara, Santa Barbara, CA 93106 USA
Hake, Kathleen
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Mellor, Blake
Pittluck, Matt
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机构:Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA
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Bucknell Univ, Dept Math, Lewisburg, PA 17837 USAUniv Naples Federico II, Dipartimento Matemat & Applicaz R Caccioppoli, Via Cintia Monte S Angelo, I-80126 Naples, Italy