Floyd maps to the boundaries of relatively hyperbolic groups

Victor Gerasimov

Published 2010-01-25, updated 2012-04-26Version 3

A continuous equivariant map from the Floyd boundary of a relatively hyperbolic group (RHG for short) to its Bowditch boundary is constructed. Such a map is unique unless the group is two-ended. In order to optimize the proof and the usage of the map theorem we propose two new definitions of relative hyperbolicity equivalent to the other known definitions. In our approach some "visibility" conditions in graphs are essential. We introduce a class of "visibility actions" that contains the class of relatively hyperbolic actions. The convergence property still holds for the visibility actions. We describe and make use a rather general construction of "attractor sum" of two actions of a locally compact group.