Sharper changes in topologies
Logic
2009-09-25 v1
Abstract
Becker and Kechris showed that if a Polish group G acts continuously on a Polish space X, then for any invariant Borel set B we can change the topology on X so that B becomes open, the Borel structure is preserved, and the action continues to be continuous. In this brief paper a short proof is presented for their theorem. The method also gives optimal bounds in terms of minimizing the change to the original topology.
Keywords
Cite
@article{arxiv.math/9610205,
title = {Sharper changes in topologies},
author = {Greg Hjorth},
journal= {arXiv preprint arXiv:math/9610205},
year = {2009}
}