English

Alternatives for pseudofinite groups

Group Theory 2012-05-17 v1 Logic

Abstract

The famous Tits' alternative states that a linear group either contains a nonabelian free group or is soluble-by-(locally finite). We study in this paper similar alternatives in pseudofinite groups. We show for instance that an 0\aleph_{0}-saturated pseudofinite group either contains a subsemigroup of rank 22 or is nilpotent-by-(uniformly locally finite). We call a class of finite groups GG weakly of bounded rank if the radical rad(G)rad(G) has a bounded Pr\"ufer rank and the index of the sockel of G/rad(G)G/rad(G) is bounded. We show that an 0\aleph_{0}-saturated pseudo-(finite weakly of bounded rank) group either contains a nonabelian free group or is nilpotent-by-abelian-by-(uniformly locally finite). We also obtain some relations between this kind of alternatives and amenability.

Keywords

Cite

@article{arxiv.1205.3533,
  title  = {Alternatives for pseudofinite groups},
  author = {Abderezak Ould Houcine and Françoise Point},
  journal= {arXiv preprint arXiv:1205.3533},
  year   = {2012}
}
R2 v1 2026-06-21T21:04:45.274Z