The search session has expired. Please query the service again.

The search session has expired. Please query the service again.

Displaying similar documents to “The G δ -topology and incompactness of ω α ”

The sizes of relatively compact T 1 -spaces

Winfried Just (1996)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

The relativization of Gryzlov’s theorem about the size of compact T 1 -spaces with countable pseudocharacter is false.

Local cardinal functions of H-closed spaces

Angelo Bella, Jack R. Porter (1996)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

The cardinal functions of pseudocharacter, closed pseudocharacter, and character are used to examine H-closed spaces and to contrast the differences between H-closed and minimal Hausdorff spaces. An H-closed space X is produced with the properties that | X | > 2 2 ψ ( X ) and ψ ¯ ( X ) > 2 ψ ( X ) .

Spaces with large star cardinal number

Yan-Kui Song (2012)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

In this paper, we prove the following statements: (1) For any cardinal κ , there exists a Tychonoff star-Lindelöf space X such that a ( X ) ≥ κ . (2) There is a Tychonoff discretely star-Lindelöf space X such that a a ( X ) does not exist. (3) For any cardinal κ , there exists a Tychonoff pseudocompact σ -starcompact space X such that st - l ( X ) ≥ κ .

More on κ -Ohio completeness

D. Basile (2011)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

We study closed subspaces of κ -Ohio complete spaces and, for κ uncountable cardinal, we prove a characterization for them. We then investigate the behaviour of products of κ -Ohio complete spaces. We prove that, if the cardinal κ + is endowed with either the order or the discrete topology, the space ( κ + ) κ + is not κ -Ohio complete. As a consequence, we show that, if κ is less than the first weakly inaccessible cardinal, then neither the space ω κ + , nor the space ℝ κ + is κ -Ohio complete.