### 8 maj 2008, kl 14.15-15.10, Tom Ward (University of East Anglia):
Rigidity and entropy geometry

**Abstract.**
Abelian measure rigidity
(situations where measures invariant
by several commuting maps are forced
to be algebraic in nature) has found
many applications. In the case of
zero-dimensional algebraic systems,
a very simple approach to proving
measure rigidity may be given using
the geometry of how the systems
produce entropy. (Joint work with
Manfred Einsiedler)