Ultracompanions of subsets of a group
| Autor: | Protasov, I., Slobodianiuk, S. |
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| Rok vydání: | 2013 |
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| Druh dokumentu: | Working Paper |
| Popis: | Let $G$ be a group, $\beta G$ is the Stone-$\check{C}$ech compactification of $\beta G$ endowed with the structure of a right topological semigroup, $G^*=\beta G\setminus G$. Given any subset $A$ of $G$ and $p\in G^*$, we define the $p$-companion $\vt_p(A)=A^*\cap Gp$ of $A$, and characterize the subsets with finite and discrete ultracompanions. |
| Databáze: | arXiv |
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