Projections and relative hyperbolicity
arXiv:1010.4552
Abstract
We give an alternative definition of relative hyperbolicity based on properties of closest-point projections on peripheral subgroups. We also derive a distance formula for relatively hyperbolic groups, similar to the one for mapping class groups.
The previous version has been split, the present version is a revision of the first part of the old version. The second part is now called "Tree-graded asymptotic cones"