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.
Cite this article
Alessandro Sisto, Projections and relative hyperbolicity. Enseign. Math. 59 (2013), no. 1/2, pp. 165–181DOI 10.4171/LEM/59-1-6