Ultrafilters on \(G\)-spaces
For a discrete group \(G\) and a discrete \(G\)-space \(X\), we identify the Stone-Cech compactifications \(\beta G\) and \(\beta X\) with the sets of all ultrafilters on \(G\) and \(X\), and apply the natural action of \(\beta G\) on \(\beta X\) to characterize large, thick, thin, sparse and scatte...
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| Datum: | 2015 |
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| Sprache: | English |
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Lugansk National Taras Shevchenko University
2015
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| Online Zugang: | https://admjournal.luguniv.edu.ua/index.php/adm/article/view/69 |
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admjournalluguniveduua-article-692015-09-28T11:22:08Z Ultrafilters on \(G\)-spaces Petrenko, O. V. Protasov, I. V. \(G\)-space, ultrafilters, ultracompanion, \(G\)-selective ultrafilter, \(G\)-Ramsey ultrafilter, \(T\)-point, ballean, asymorphism 05D10, 22A15, 54H20 For a discrete group \(G\) and a discrete \(G\)-space \(X\), we identify the Stone-Cech compactifications \(\beta G\) and \(\beta X\) with the sets of all ultrafilters on \(G\) and \(X\), and apply the natural action of \(\beta G\) on \(\beta X\) to characterize large, thick, thin, sparse and scattered subsets of \(X\). We use \(G\)-invariant partitions and colorings to define \(G\)-selective and \(G\)-Ramsey ultrafilters on \(X\). We show that, in contrast to the set-theoretical case, these two classes of ultrafilters are distinct. We consider also universally thin ultrafilters on \(\omega\), the \(T\)-points, and study interrelations between these ultrafilters and some classical ultrafilters on \(\omega\). Lugansk National Taras Shevchenko University 2015-09-28 Article Article Peer-reviewed Article application/pdf https://admjournal.luguniv.edu.ua/index.php/adm/article/view/69 Algebra and Discrete Mathematics; Vol 19, No 2 (2015) 2415-721X 1726-3255 en https://admjournal.luguniv.edu.ua/index.php/adm/article/view/69/18 Copyright (c) 2015 Algebra and Discrete Mathematics |
| institution |
Algebra and Discrete Mathematics |
| baseUrl_str |
|
| datestamp_date |
2015-09-28T11:22:08Z |
| collection |
OJS |
| language |
English |
| topic |
\(G\)-space ultrafilters ultracompanion \(G\)-selective ultrafilter \(G\)-Ramsey ultrafilter \(T\)-point ballean asymorphism 05D10 22A15 54H20 |
| spellingShingle |
\(G\)-space ultrafilters ultracompanion \(G\)-selective ultrafilter \(G\)-Ramsey ultrafilter \(T\)-point ballean asymorphism 05D10 22A15 54H20 Petrenko, O. V. Protasov, I. V. Ultrafilters on \(G\)-spaces |
| topic_facet |
\(G\)-space ultrafilters ultracompanion \(G\)-selective ultrafilter \(G\)-Ramsey ultrafilter \(T\)-point ballean asymorphism 05D10 22A15 54H20 |
| format |
Article |
| author |
Petrenko, O. V. Protasov, I. V. |
| author_facet |
Petrenko, O. V. Protasov, I. V. |
| author_sort |
Petrenko, O. V. |
| title |
Ultrafilters on \(G\)-spaces |
| title_short |
Ultrafilters on \(G\)-spaces |
| title_full |
Ultrafilters on \(G\)-spaces |
| title_fullStr |
Ultrafilters on \(G\)-spaces |
| title_full_unstemmed |
Ultrafilters on \(G\)-spaces |
| title_sort |
ultrafilters on \(g\)-spaces |
| description |
For a discrete group \(G\) and a discrete \(G\)-space \(X\), we identify the Stone-Cech compactifications \(\beta G\) and \(\beta X\) with the sets of all ultrafilters on \(G\) and \(X\), and apply the natural action of \(\beta G\) on \(\beta X\) to characterize large, thick, thin, sparse and scattered subsets of \(X\). We use \(G\)-invariant partitions and colorings to define \(G\)-selective and \(G\)-Ramsey ultrafilters on \(X\). We show that, in contrast to the set-theoretical case, these two classes of ultrafilters are distinct. We consider also universally thin ultrafilters on \(\omega\), the \(T\)-points, and study interrelations between these ultrafilters and some classical ultrafilters on \(\omega\). |
| publisher |
Lugansk National Taras Shevchenko University |
| publishDate |
2015 |
| url |
https://admjournal.luguniv.edu.ua/index.php/adm/article/view/69 |
| work_keys_str_mv |
AT petrenkoov ultrafiltersongspaces AT protasoviv ultrafiltersongspaces |
| first_indexed |
2025-12-02T15:46:28Z |
| last_indexed |
2025-12-02T15:46:28Z |
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1850412172648120320 |