A note on spaces with countable extent

Yan-Kui Song

Commentationes Mathematicae Universitatis Carolinae (2017)

  • Volume: 58, Issue: 3, page 397-399
  • ISSN: 0010-2628

Abstract

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Let P be a topological property. A space X is said to be star P if whenever 𝒰 is an open cover of X , there exists a subspace A X with property P such that X = S t ( A , 𝒰 ) . In this note, we construct a Tychonoff pseudocompact SCE-space which is not star Lindelöf, which gives a negative answer to a question of Rojas-Sánchez and Tamariz-Mascarúa.

How to cite

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Song, Yan-Kui. "A note on spaces with countable extent." Commentationes Mathematicae Universitatis Carolinae 58.3 (2017): 397-399. <http://eudml.org/doc/294097>.

@article{Song2017,
abstract = {Let $P$ be a topological property. A space $X$ is said to be star P if whenever $\mathcal \{U\}$ is an open cover of $X$, there exists a subspace $A\subseteq X$ with property $P$ such that $X=St(A,\mathcal \{U\})$. In this note, we construct a Tychonoff pseudocompact SCE-space which is not star Lindelöf, which gives a negative answer to a question of Rojas-Sánchez and Tamariz-Mascarúa.},
author = {Song, Yan-Kui},
journal = {Commentationes Mathematicae Universitatis Carolinae},
keywords = {star properties; star Lindelöf; space with star countable extent},
language = {eng},
number = {3},
pages = {397-399},
publisher = {Charles University in Prague, Faculty of Mathematics and Physics},
title = {A note on spaces with countable extent},
url = {http://eudml.org/doc/294097},
volume = {58},
year = {2017},
}

TY - JOUR
AU - Song, Yan-Kui
TI - A note on spaces with countable extent
JO - Commentationes Mathematicae Universitatis Carolinae
PY - 2017
PB - Charles University in Prague, Faculty of Mathematics and Physics
VL - 58
IS - 3
SP - 397
EP - 399
AB - Let $P$ be a topological property. A space $X$ is said to be star P if whenever $\mathcal {U}$ is an open cover of $X$, there exists a subspace $A\subseteq X$ with property $P$ such that $X=St(A,\mathcal {U})$. In this note, we construct a Tychonoff pseudocompact SCE-space which is not star Lindelöf, which gives a negative answer to a question of Rojas-Sánchez and Tamariz-Mascarúa.
LA - eng
KW - star properties; star Lindelöf; space with star countable extent
UR - http://eudml.org/doc/294097
ER -

References

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  1. Aiken L.P., 10.1016/j.topol.2011.06.032, Topology Appl. 158 (2011), 1732–1737. Zbl1223.54029MR2812483DOI10.1016/j.topol.2011.06.032
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  4. van Douwen E.K., Reed G.M., Roscoe A.W., Tree I.J., 10.1016/0166-8641(91)90077-Y, Topology Appl. 39 (1991), 71–103. Zbl0743.54007MR1103993DOI10.1016/0166-8641(91)90077-Y
  5. Engelking R., General Topology, revised and completed edition, Heldermann, Berlin, 1989. Zbl0684.54001MR1039321
  6. Matveev M.V., A survey on star-covering properties, Topological Atlas preprint no. 330, 1998. 
  7. van Mill J., Tkachuk V.V., Wilson R.G., 10.1016/j.topol.2006.03.029, Topology Appl. 154 (2007), 2127–2134. MR2324924DOI10.1016/j.topol.2006.03.029
  8. Noble N., Countably compact and pseudocompact products, Czechoslovak Math. J. 19(3) (1969), 390–397. Zbl0184.47706MR0248717
  9. Rojas-Sánchez A.D., Tamariz-Mascarúa Á., Spaces with star countable extent, Comment. Math. Univ. Carolin. 57 (2016), no 3, 381–395. MR3554518

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