4
votes
1answer
145 views

Free groups and Kazhdan's property (T)

Showing non-amenability of a (non-abelian) free group is somewhat easy and one can do this immediately after the definition of amenability. Is there an easy proof of the fact that free groups do not ...
3
votes
2answers
114 views

Extensions and Kazhdan's Property (T)

Is Kazhdan's property (T) stable under extensions? i.e. if $G$ is an extension of a group with property (T) by a group with property (T), does it follow that $G$ has property (T)?