Exactness of locally compact groups
  We give some new characterizations of exactness for locally compact second countable groups. In particular, we prove that a locally compact second countable group is exact if and only if it admits a topologically amenable action on a compact Hausdorff space. This answers an open question by Anantharaman-Delaroche. 
Jacek Brodzki, Chris Cave and Kang Li
math.GR math.OA