On Products of Property $b_1$ |
Received:July 13, 2010 Revised:November 20, 2010 |
Key Words:
$\sigma$-product Tychonoff products property $b_1$ hereditarily property $b_1$.
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Fund Project:Supported by the National Natural Science Foundation of China (Grant Nos.10671134; 11026081). |
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Abstract: |
In this note, we present that: (1)~Let $X$=$\sigma\{X_{\alpha}:\alpha\in A\}$ be $\left| A \right|$-paracompact (resp., hereditarily $\left| A \right|$-paracompact). If every finite subproduct of ${\rm \{ } X\-\alpha: \alpha \in A {\rm \} }$ has property $b_1$ (resp., hereditarily property $b_1$), then so is $X$. (2)~Let $X$ be a P-space and $Y$ a metric space. Then, $X\times Y$ has property $b_1 $ iff $X$ has property $b_1 $. (3)~Let $X$ be a strongly zero-dimensional and compact space. Then, $X\times Y$ has property $b_1 $ iff $Y$ has property $b_1$. |
Citation: |
DOI:10.3770/j.issn:2095-2651.2012.02.012 |
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