| Title:
|
A strengthening of the Katětov-Tong insertion theorem (English) |
| Author:
|
Kubiak, Tomasz |
| Language:
|
English |
| Journal:
|
Commentationes Mathematicae Universitatis Carolinae |
| ISSN:
|
0010-2628 (print) |
| ISSN:
|
1213-7243 (online) |
| Volume:
|
34 |
| Issue:
|
2 |
| Year:
|
1993 |
| Pages:
|
357-362 |
| . |
| Category:
|
math |
| . |
| Summary:
|
Normal spaces are characterized in terms of an insertion type theorem, which implies the Katětov-Tong theorem. The proof actually provides a simple necessary and sufficient condition for the insertion of an ordered pair of lower and upper semicontinuous functions between two comparable real-valued functions. As a consequence of the latter, we obtain a characterization of completely normal spaces by real-valued functions. (English) |
| Keyword:
|
normal space |
| Keyword:
|
semicontinuous functions |
| Keyword:
|
insertion |
| Keyword:
|
limit functions |
| Keyword:
|
completely normal space |
| MSC:
|
54C30 |
| MSC:
|
54D15 |
| idZBL:
|
Zbl 0807.54023 |
| idMR:
|
MR1241744 |
| . |
| Date available:
|
2009-01-08T18:04:00Z |
| Last updated:
|
2012-04-30 |
| Stable URL:
|
http://hdl.handle.net/10338.dmlcz/118588 |
| . |
| Reference:
|
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| Reference:
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| Reference:
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| Reference:
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| Reference:
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| Reference:
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| Reference:
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| Reference:
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| Reference:
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| . |
