%0 Journal Article
%T A characterization of relative Kazhdan Property T for semidirect products with abelian groups
%A Yves Cornulier
%A Romain Tessera
%J Mathematics
%D 2009
%I arXiv
%R 10.1017/S0143385710000271
%X Let A be a locally compact abelian group, and H a locally compact group acting on A. Let G=HA be the semidirect product. We prove that the pair (G,A) has Kazhdan's Property T if and only if the only countably approximable H-invariant mean on the Borel subsets of the Pontryagin dual of A, supported at the neighbourhood of the trivial character, is the Dirac measure.
%U http://arxiv.org/abs/0911.3371v3