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Volume 37 • Number 3 • 2014 |
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Weakly Quasi-First-Countable Spaces and Box Products
Rongxin Shen and Fucai Lin
Abstract.
A space $X$ is said to be weakly quasi-first-countable if and only if for all $x \in X$, there exists countably many countable families of decreasing subsets containing $x$ such that a set $O$ is open if and only if for any $x\in O$, $O$ contains a member of each family associated to $x$. For a space $X$, we denote the countable $\sigma$-product of $X$ endowed with the box topology by $\sigma B(X)$. We prove that if $X$ is first-countable and locally compact, then $\sigma B(X)$ is weakly quasi-first-countable, which gives a general method to construct weakly quasi-first-countable spaces which are neither weakly first-countable nor quasi-first-countable.
2010 Mathematics Subject Classification: 54A05, 54D15
Full text: PDF
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