Some computations of 1-cohomology groups and construction of non orbit equivalent actions
Operator Algebras
2007-05-23 v6 Group Theory
Abstract
For each group having an infinite normal subgroup with the relative property (T) (for instance where is infinite with property (T) and is arbitrary), and any countable abelian group we construct free ergodic measure preserving actions of on the probability space such that the 1'st cohomology group of , , is equal to Char. We deduce that has uncountably many non stably orbit equivalent actions. We also calculate 1-cohomology groups and show existence of ``many'' non stably orbit equivalent actions for free products of groups as above.
Cite
@article{arxiv.math/0407199,
title = {Some computations of 1-cohomology groups and construction of non orbit equivalent actions},
author = {Sorin Popa},
journal= {arXiv preprint arXiv:math/0407199},
year = {2007}
}
Comments
24 pages (final version, with slight additions and change of title on 09/20/04)