arXiv subjects
Publications and source records attributed to Antoine Clais.
We study the buildings in which parallelism of residues is an equivalence relation. If the building admits a group action, we describe how parallel residues are related to residues with equal stabilizers. This permits to retrieve the fact that in a Coxeter group or in a graph product, intersections of parabolic subgroups are parabolic.
The goal of this survey is to present combinatorial modulus that have been recently used to study quasi-conformal properties of boundaries of hyperbolic groups. First, we will recall well known rigidity results and questions that motivated the introduction of these tools. Then we will define combinatorial modulus and the combinatorial Loewner property that provide new approaches to rigidity questions. Finally, we will describe some applications of these tools through recent results. ----- Le but de ce survol est de présenter les modules combinatoires récemment utilisés pour étudier les propriétés quasi-conformes des bords des groupes hyperboliques. Dans un premier temps, on rappellera quelques résultats et questions de rigidité bien connus qui ont motivés l'introduction de ces outils. Puis on définira les modules combinatoires et la propriété de Löwner combinatoire qui offrent une nouvelle approche pour résoudre des problèmes ouverts depuis longtemps. Enfin, on décrira des applications concrètes de ces outils à travers quelques résultats récents.
In this note, we use some combinatorial modulus on the boundary of a right-angled hyperbolic building to control its conformal dimension. The lower bound obtained is optimal in the case of Fuchsian buildings.
In this article, we discuss the quasiconformal structure of boundaries of right-angled hyperbolic buildings using combinatorial tools. In particular we exhibit some examples of buildings of dimension 3 and 4 whose boundaries satisfy the combinatorial Loewner property. This property is a weak version of the Loewner property. This is motivated by the fact that the quasiconformal structure of the boundary led to many results of rigidity in hyperbolic spaces since G.D. Mostow. In the case of buildings of dimension 2, many work have been done by M. Bourdon and H. Pajot. In particular, the Loewner property on the boundary permitted them to prove the quasi-isometry rigidity of right-angled Fuchsian buildings.