Separable and tree-like asymptotic cones of groups

Using methods from nonstandard analysis, we will discuss which metric spaces can be realized as ultralimits (in particular, asymptotic cones). For example, we will show that any separable ultralimit is proper. Applying the results we will find in the context of groups, we will classify the real tree...

Verfasser: Sisto, Alessandro
FB/Einrichtung:FB 10: Mathematik und Informatik
Dokumenttypen:Artikel
Medientypen:Text
Erscheinungsdatum:2012
Publikation in MIAMI:23.10.2012
Datum der letzten Änderung:07.05.2015
Quelle:Münster Journal of Mathematics, 5 (2012), S. 233-248
Angaben zur Ausgabe:[Electronic ed.]
Fachgebiet (DDC):510: Mathematik
Lizenz:InC 1.0
Sprache:English
Format:PDF-Dokument
URN:urn:nbn:de:hbz:6-88399586094
Permalink:https://nbn-resolving.de/urn:nbn:de:hbz:6-88399586094
Onlinezugriff:mjm_vol_5_12.pdf

Using methods from nonstandard analysis, we will discuss which metric spaces can be realized as ultralimits (in particular, asymptotic cones). For example, we will show that any separable ultralimit is proper. Applying the results we will find in the context of groups, we will classify the real trees appearing as asymptotic cones of (not necessarily hyperbolic) finitely generated groups. Also, we show that all proper metric spaces can be realized as asymptotic cones.