| Title:
|
On hereditary normality of $\omega ^*$, Kunen points and character $\omega_{1}$ (English) |
| Author:
|
Logunov, Sergei |
| Language:
|
English |
| Journal:
|
Commentationes Mathematicae Universitatis Carolinae |
| ISSN:
|
0010-2628 (print) |
| ISSN:
|
1213-7243 (online) |
| Volume:
|
62 |
| Issue:
|
4 |
| Year:
|
2021 |
| Pages:
|
507-511 |
| Summary lang:
|
English |
| . |
| Category:
|
math |
| . |
| Summary:
|
We show that $\omega ^{*}\setminus \{p\}$ is not normal, if $p$ is a limit point of some countable subset of $\omega ^{*}$, consisting of points of character $\omega _{1}$. Moreover, such a point $p$ is a Kunen point and a super Kunen point. (English) |
| Keyword:
|
non-normality point |
| Keyword:
|
butterfly point |
| Keyword:
|
Kunen point |
| Keyword:
|
super Kunen point |
| MSC:
|
54D15 |
| MSC:
|
54D35 |
| MSC:
|
54D40 |
| MSC:
|
54D80 |
| MSC:
|
54E35 |
| MSC:
|
54G20 |
| idZBL:
|
Zbl 07511577 |
| idMR:
|
MR4405820 |
| DOI:
|
10.14712/1213-7243.2021.032 |
| . |
| Date available:
|
2022-02-21T13:32:15Z |
| Last updated:
|
2024-01-01 |
| Stable URL:
|
http://hdl.handle.net/10338.dmlcz/149373 |
| . |
| Reference:
|
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| Reference:
|
[2] Błaszczyk A., Szymański A.: Some non-normal subspaces of the Čech–Stone compactification of a discrete space.Proc. Eighth Winter School on Abstract Analysis, Czechoslovak Academy of Sciences, Praha, 1980, pages 35–38. |
| Reference:
|
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| Reference:
|
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| Reference:
|
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| Reference:
|
[6] Rajagopalan M.: $\beta N-N-\{p\}$ is not normal.J. Indian Math. Soc. (N.S.) 36 (1972), 173–176. MR 0321012 |
| Reference:
|
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| Reference:
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| . |
