Texas A&M University, Department of
Mathematics, 317 Milner Hall, 29th of November 2005, 3:00-3:50
Groups and Dynamics Seminar
Ergodic properties
of boundary actions and Nielsen's method
Vadim Kaimanovich of International
Univesiy Bremen, Germany
The talk is based on a joint work with S. Grigorchuk and T. Nagnibeda.
We study the basic ergodic properties (ergodicity and conservativity)
of the action of a subgroup of a free group on the boundary of the
ambient group with respect to the uniform measure. We relate these
properties with natural geometric objects (the Schreier graph, its
geodesic spanning subtrees and the associated Nielsen systems of
generators) and their quantitative characteristics (growth, cogrowth
etc.) .