| Title:
             | 
Coronas of ultrametric spaces (English) | 
| Author:
             | 
Protasov, I. V. | 
| Language:
             | 
English | 
| Journal:
             | 
Commentationes Mathematicae Universitatis Carolinae | 
| ISSN:
             | 
0010-2628 (print) | 
| ISSN:
             | 
1213-7243 (online) | 
| Volume:
             | 
52 | 
| Issue:
             | 
2 | 
| Year:
             | 
2011 | 
| Pages:
             | 
303-307 | 
| Summary lang:
             | 
English | 
| . | 
| Category:
             | 
math | 
| . | 
| Summary:
             | 
We show that, under CH, the corona of a countable ultrametric space is homeomorphic to $\omega^*$. As a corollary, we get the same statements for the Higson's corona of a proper ultrametric space and the space of ends of a countable locally finite group. (English) | 
| Keyword:
             | 
Stone-Čech compactification | 
| Keyword:
             | 
ultrametric space | 
| Keyword:
             | 
corona | 
| Keyword:
             | 
Higson's corona | 
| Keyword:
             | 
space of ends | 
| MSC:
             | 
54D35 | 
| MSC:
             | 
54D80 | 
| MSC:
             | 
54G05 | 
| idZBL:
             | 
Zbl 1240.54087 | 
| idMR:
             | 
MR2849052 | 
| . | 
| Date available:
             | 
2011-05-17T08:43:44Z | 
| Last updated:
             | 
2013-09-22 | 
| Stable URL:
             | 
http://hdl.handle.net/10338.dmlcz/141502 | 
| . | 
| Reference:
             | 
[1] Dranishnikov A.: Asymptotic topology.Russian Math. Surveys 55 (2000), 1085–1129. Zbl 1028.54032, MR 1840358, 10.1070/RM2000v055n06ABEH000334 | 
| Reference:
             | 
[2] Engelking R.: General Topology.PWN, Warzsawa, 1985. Zbl 0684.54001 | 
| Reference:
             | 
[3] Houghton C.H.: Ends of groups and associated first cohomology groups.J. London Math. Soc. 6 (1972), 81–92. MR 0316595, 10.1112/jlms/s2-6.1.81 | 
| Reference:
             | 
[4] van Mill J.: Introduction to $\beta \omega $.in Handbook of Set-Theoretical Topology, Chapter 11, Elsevier Science Publishers B.V., Amsterdam, 1984. Zbl 0555.54004 | 
| Reference:
             | 
[5] Protasov I.V.: Normal ball structures.Math. Stud. 20 (2003), 3–16. Zbl 1053.54503, MR 2019592 | 
| Reference:
             | 
[6] Protasov I.V.: Coronas of balleans.Topology Appl. 149 (2005), 149–160. Zbl 1068.54036, MR 2130861, 10.1016/j.topol.2004.09.005 | 
| Reference:
             | 
[7] Protasov I., Zarichnyi M.: General asymptology.Math. Stud. Monogr. Ser. 12, VNTL, Lviv, 2007. Zbl 1172.54002, MR 2406623 | 
| . |