关于有限支撑元素的NY紧空间类及相关类
On the class of NY compact spaces of finitely supported elements and related classes
AI总结:
本文通过σ-积嵌入条件给出ω-Corson与NY紧空间的新刻画,构造反例回答Kubiś和Leiderman的问题,并证明NY紧性由函数空间C_p(K)的拓扑结构决定。
摘要:
我们证明,一个紧空间 $K$ 能嵌入到紧可度量空间的 $σ$-积(区间的 $σ$-积)中,当且仅当 $K$ 是(强可数维的)遗传metalindelöf空间,并且 $K$ 的每个子空间都有一个非空的相对开第二可数子集。这为 $ω$-Corson 紧空间和 $NY$ 紧空间提供了新的刻画。我们给出一个一致Eberlein紧空间的例子,它不能以使得 $σ$-积在像中稠密的方式嵌入到紧度量空间的乘积中。特别地,这回答了Kubiś和Leiderman的一个问题。我们还证明,对于一个紧空间 $K$,其为 $NY$ 紧的性质由配备点态收敛拓扑的 $K$ 上连续实值函数空间 $C_p(K)$ 的拓扑结构所决定。这改进了Zakrzewski最近的一个结果。
英文摘要:
We prove that a compact space $K$ embeds into a $σ$-product of compact metrizable spaces ($σ$-product of intervals) if and only if $K$ is (strongly countable-dimensional) hereditarily metalindelöf and every subspace of $K$ has a nonempty relative open second-countable subset. This provides novel characterizations of $ω$-Corson and $NY$ compact spaces. We give an example of a uniform Eberlein compact space that does not embed into a product of compact metric spaces in such a way that the $σ$-product is dense in the image. In particular, this answers a question of Kubiś and Leiderman. We also show that for a compact space $K$ the property of being $NY$ compact is determined by the topological structure of the space $C_p(K)$ of continuous real-valued functions of $K$ equipped with the pointwise convergence topology. This refines a recent result of Zakrzewski.
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