• Title of article

    Normality in products with a countable factor

  • Author/Authors

    Szeptycki، نويسنده , , Paul J.، نويسنده ,

  • Issue Information
    دوماهنامه با شماره پیاپی سال 2010
  • Pages
    7
  • From page
    1622
  • To page
    1628
  • Abstract
    The class of normal spaces that have normal product with every countable space is considered. A countably compact normal space X and a countable Y such that X × Y is not normal is constructed assuming CH. Also, ⋄ is used to construct a perfectly normal countably compact X and a countable Y such that X × Y is not normal. The question whether a Dowker space can have normal product with itself is considered. It is shown that if X is Dowker and contains any countable non-discrete subspace, then X 2 is not normal. It follows that a product of a Dowker space and a countable space is normal if and only if the countable space is discrete. If X is Rudinʹs ZFC Dowker space, then X 2 is normal. An example of a Dowker space of cardinality ℵ 2 with normal square is constructed assuming ⋄ ω 2 ∗ .
  • Keywords
    Countable spaces , Normal space , Products , Countably compact , Counter-examples , Dowker space
  • Journal title
    Topology and its Applications
  • Serial Year
    2010
  • Journal title
    Topology and its Applications
  • Record number

    1582566