Displaying similar documents to “Generalized tri-quotient maps and Čech-completeness”

On ℒ -starcompact spaces

Yan-Kui Song (2006)

Czechoslovak Mathematical Journal

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A space X is ℒ -starcompact if for every open cover 𝒰 of X , there exists a Lindelöf subset L of X such that S t ( L , 𝒰 ) = X . We clarify the relations between ℒ -starcompact spaces and other related spaces and investigate topological properties of ℒ -starcompact spaces. A question of Hiremath is answered.

On k -spaces and k R -spaces

Jinjin Li (2005)

Czechoslovak Mathematical Journal

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In this note we study the relation between k R -spaces and k -spaces and prove that a k R -space with a σ -hereditarily closure-preserving k -network consisting of compact subsets is a k -space, and that a k R -space with a point-countable k -network consisting of compact subsets need not be a k -space.

Mapping theorems on ℵ -spaces

Masami Sakai (2008)

Commentationes Mathematicae Universitatis Carolinae

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In this paper we improve some mapping theorems on ℵ -spaces. For instance we show that an ℵ -space is preserved by a closed and countably bi-quotient map. This is an improvement of Yun Ziqiu’s theorem: an ℵ -space is preserved by a closed and open map.