groups are almost convex and have a sub-cubic Dehn function.
Length of involutions and classification of finite Coxeter groups. (Longueur des involutions et classification des groupes de Coxeter finis.)
Lengths of involutions in Coxeter groups.
Les groupes de triangles sont déterminés par leur spectre des longueurs
On décrit le début du spectre des longueurs des groupes de triangles ayant un angle droit et on montre que le spectre des longueurs caractérise la classe d’isométrie d’un tel groupe.
Les groupes hyperboliques
L'image d'un groupe dans un groupe hyperbolique.
Limit groups and groups acting freely on -trees.
Limits of relatively hyperbolic groups and Lyndon’s completions
We describe finitely generated groups universally equivalent (with constants from in the language) to a given torsion-free relatively hyperbolic group with free abelian parabolics. It turns out that, as in the free group case, the group embeds into the Lyndon’s completion of the group , or, equivalently, embeds into a group obtained from by finitely many extensions of centralizers. Conversely, every subgroup of containing is universally equivalent to . Since finitely generated...