当前位置: X-MOL 学术Topol. Appl. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Scattered compact sets in continuous images of Čech-complete spaces
Topology and its Applications ( IF 0.6 ) Pub Date : 2020-08-01 , DOI: 10.1016/j.topol.2020.107213
Taras Banakh , Bogdan Bokalo , Vladimir Tkachuk

Assume hat a functionally Hausdorff space $X$ is a continuous image of a \v{C}ech complete space $P$ with Lindel\"of number $l(P)<\mathfrak c$. Then the following conditions are equivalent: (i) every compact subset of $X$ is scattered, (ii) for every continuous map $f:X\to Y$ to a functionally Hausdorff space $Y$ the image $f(X)$ has cardinality $|f(X)|\le \max\{l(P),\psi(Y)\}$, (iii) no continuous map $f:X\to[0,1]$ is surjective. Also we prove the equivalence of the conditions: (a) $\omega_1<\mathfrak b$, (b) a K-analytic space $X$ (with a unique non-isolated point) is countable if and only if every compact subset of $X$ is countable.

中文翻译:

Čech-完全空间的连续图像中的分散紧集

假设函数 Hausdorff 空间 $X$ 是 \v{C}ech 完全空间 $P$ 的连续图像,其中包含数为 $l(P)<\mathfrak c$ 的 Lindel\"。那么以下条件是等价的: (i) $X$ 的每个紧致子集都是分散的, (ii) 对于每个连续映射 $f:X\to Y$ 到函数 Hausdorff 空间 $Y$,图像 $f(X)$ 具有基数 $|f( X)|\le \max\{l(P),\psi(Y)\}$, (iii) 没有连续映射 $f:X\to[0,1]$ 是满射的。我们也证明了等价条件:(a) $\omega_1<\mathfrak b$, (b) K-解析空间 $X$(具有唯一的非孤立点)是可数的当且仅当 $X$ 的每个紧子集都是可数的.
更新日期:2020-08-01
down
wechat
bug