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On p -sequential p -compact spaces

Salvador García-Ferreira, Angel Tamariz-Mascarúa (1993)

Commentationes Mathematicae Universitatis Carolinae

It is shown that a space X is L ( μ p ) -Weakly Fréchet-Urysohn for p ω * iff it is L ( ν p ) -Weakly Fréchet-Urysohn for arbitrary μ , ν < ω 1 , where μ p is the μ -th left power of p and L ( q ) = { μ q : μ < ω 1 } for q ω * . We also prove that for p -compact spaces, p -sequentiality and the property of being a L ( ν p ) -Weakly Fréchet-Urysohn space with ν < ω 1 , are equivalent; consequently if X is p -compact and ν < ω 1 , then X is p -sequential iff X is ν p -sequential (Boldjiev and Malyhin gave, for each P -point p ω * , an example of a compact space X p which is 2 p -Fréchet-Urysohn and it is...

On pseudo-radial spaces

Aleksander V. Arhangel'skii, Romano Isler, Gino Tironi (1986)

Commentationes Mathematicae Universitatis Carolinae

On quasi-p-bounded subsets

M. Sanchis, A. Tamariz-Mascarúa (1999)

Colloquium Mathematicae

The notion of quasi-p-boundedness for p ∈ ω * is introduced and investigated. We characterize quasi-p-pseudocompact subsets of β(ω) containing ω, and we show that the concepts of RK-compatible ultrafilter and P-point in ω * can be defined in terms of quasi-p-pseudocompactness. For p ∈ ω * , we prove that a subset B of a space X is quasi-p-bounded in X if and only if B × P R K ( p ) is bounded in X × P R K ( p ) , if and only if c l β ( X × P R K ( p ) ) ( B × P R K ( p ) ) = c l β X B × β ( ω ) , where P R K ( p ) is the set of Rudin-Keisler predecessors of p.

On some fan-tightness type properties

J. Valuyeva (1998)

Commentationes Mathematicae Universitatis Carolinae

Properties similar to countable fan-tightness are introduced and compared to countable tightness and countable fan-tightness. These properties are also investigated with respect to function spaces and certain classes of continuous mappings.

On spaces with the property of weak approximation by points

Angelo Bella (1994)

Commentationes Mathematicae Universitatis Carolinae

A sufficient condition that the product of two compact spaces has the property of weak approximation by points (briefly WAP) is given. It follows that the product of the unit interval with a compact WAP space is also a WAP space.

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