Yan-Kui Song, Shu-Nian Zheng (2010)
Mathematica Bohemica
Similarity:
A subset of a space is almost countably compact in if for every countable cover of by open subsets of , there exists a finite subfamily of such that . In this paper we investigate the relationship between almost countably compact spaces and relatively almost countably compact subsets, and also study various properties of relatively almost countably compact subsets.
John J. Schommer, Mary Anne Swardson (2001)
Commentationes Mathematicae Universitatis Carolinae
Similarity:
We provide a new generalization of realcompactness based on ultrafilters of cozero sets and contrast it with almost realcompactness.
Yankui Song (2009)
Mathematica Bohemica
Similarity:
A subspace of a space is almost Lindelöf (strongly almost Lindelöf) in if for every open cover of (of by open subsets of ), there exists a countable subset of such that . In this paper we investigate the relationships between relatively almost Lindelöf subset and relatively strongly almost Lindelöf subset by giving some examples, and also study various properties of relatively almost Lindelöf subsets and relatively strongly almost Lindelöf subsets.
A. Maliszewski, T. Natkaniec (1993)
Revista de la Real Academia de Ciencias Exactas Físicas y Naturales
Similarity: