Countable structure does not have a free uncountable automorphism group
Logic
2007-05-23 v1
Abstract
Solecki proved that the group of automorphisms of a countable structure cannot be an uncountable free abelian group. See more in Just, Shelah and Thomas math.LO/0003120 where as a by product we can say something on on uncountable structures. We prove here the following Theorem: If A is a countable model, then Aut(M) cannot be a free uncountable group.
Cite
@article{arxiv.math/0010305,
title = {Countable structure does not have a free uncountable automorphism group},
author = {Saharon Shelah},
journal= {arXiv preprint arXiv:math/0010305},
year = {2007}
}