A note on star Lindelöf, first countable and normal spaces
A topological space $X$ is said to be star Lindelöf if for any open cover $\mathcal U$ of $X$ there is a Lindelöf subspace $A \subset X$ such that $øperatorname{St}(A, \mathcal U)=X$. The "extent" $e(X)$ of $X$ is the supremum of the cardinalities of closed discrete subsets of $X$....
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| Format: | Article |
| Language: | English |
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Institute of Mathematics of the Czech Academy of Science
2017-12-01
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| Series: | Mathematica Bohemica |
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| Online Access: | http://mb.math.cas.cz/full/142/4/mb142_4_7.pdf |