Local cardinal functions of H-closed spaces

Angelo Bella; Jack R. Porter

The $G_{δ}$ -topology and incompactness of $ω^{α}$

Isaac Gorelic (1996)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

We establish a relation between covering properties (e.gĿindelöf degree) of two standard topological spaces (Lemmas 4 and 5). Some cardinal inequalities follow as easy corollaries.

On the cardinality of functionally Hausdorff spaces

Alessandro Fedeli (1996)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

In this paper two new cardinal functions are introduced and investigated. In particular the following two theorems are proved: (i) If $X$ is a functionally Hausdorff space then $| X | \leq 2^{f s (X) ψ_{τ} (X)}$ ; (ii) Let $X$ be a functionally Hausdorff space with $f s (X) \leq κ$ . Then there is a subset $S$ of $X$ such that $| S | \leq 2^{κ}$ and $X = ⋃ {c l_{τ θ} (A) : A \in {[S]}^{\leq κ}}$ .

Displaying similar documents to “Local cardinal functions of H-closed spaces”

The G δ -topology and incompactness of ω α

On the cardinality of functionally Hausdorff spaces

The $G_{δ}$ -topology and incompactness of $ω^{α}$