In this paper, we prove the following result. Let X be a complete metric space of weight w(X) and H⊆X be a set such that w(X)<|H|<c. Then there is no continuous bijection of the subspace X∖H onto a σ-compact space. As a result, there is no continuous bijection of the subspace X∖H onto a Polish space. Thus, it has been proved that metric compact spaces are not aτ-spaces for any uncountable cardinal number τ. This result answers the question asked by E.G. Pytkeev in his coauthored work “On the properties of subclasses of weakly dyadic compact sets” to be published in the Siberian Mathematical Journal.
Original languageEnglish
Pages (from-to)351-355
Number of pages5
JournalDoklady Mathematics
Volume106
Issue number2
DOIs
Publication statusPublished - 1 Nov 2022

    ASJC Scopus subject areas

  • Mathematics(all)

    WoS ResearchAreas Categories

  • Mathematics

ID: 33223826