groups are almost convex and have a sub-cubic Dehn function.
L²-homology and reciprocity for right-angled Coxeter groups
Let W be a Coxeter group and let μ be an inner product on the group algebra ℝW. We say that μ is admissible if it satisfies the axioms for a Hilbert algebra structure. Any such inner product gives rise to a von Neumann algebra containing ℝW. Using these algebras and the corresponding von Neumann dimensions we define -Betti numbers and an -Euler charactersitic for W. We show that if the Davis complex for W is a generalized homology manifold, then these Betti numbers satisfy a version of Poincaré...
Large scale Sobolev inequalities on metric measure spaces and applications.
Lateral and Dedekind completions of strongly projectable lattice ordered groups
Lateral completion of a projectable lattice ordered group
Lattices and bases of Coxeter groups. (Treillis et bases des groups de Coxeter.)
Lattices of partially local Fitting classes.
Le genre d'un groupe nilpotent avec opérateurs.
Le groupe d'automorphismes du groupe modulaire
Le but de cet article est de donner une autre démonstration plus simple du théorème d’Ivanov (Théorème 1) qui assure que le groupe de toutes les difféotopies d’une surface orientable et fermée de genre est complet. En étudiant l’action d’un automorphisme quelconque du groupe sur les difféotopies d’ordre fini, on montre que les involutions hyperelliptiques sont globalement préservées. Le théorème d’Ivanov est alors une conséquence d’un résultat de Dyer et Grossmann qui affirm que le groupe...
Le problème de l'associativité des monoïdes et le problème des mots pour les demi-groupes ; algèbres partielles et chaînes élémentaires
Left-Garside categories, self-distributivity, and braids
In connection with the emerging theory of Garside categories, we develop the notions of a left-Garside category and of a locally left-Garside monoid. In this framework, the relationship between the self-distributivity law LD and braids amounts to the result that a certain category associated with LD is a left-Garside category, which projects onto the standard Garside category of braids. This approach leads to a realistic program for establishing the Embedding Conjecture of [Dehornoy, Braids and...
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
Les immeubles des groupes de tresses généralisés.
Lexicographic product decompositions of cyclically ordered groups
Lie perfect, Lie central extension and generalization of nilpotency in multiplicative Lie algebras
This paper aims to introduce and explore the concept of Lie perfect multiplicative Lie algebras, with a particular focus on their connections to the central extension theory of multiplicative Lie algebras. The primary objective is to establish and provide proof for a range of results derived from Lie perfect multiplicative Lie algebras. Furthermore, the study extends the notion of Lie nilpotency by introducing and examining the concept of local nilpotency within multiplicative Lie algebras. The...
Lifting of homeomorphisms to branched coverings of a disk
We consider a simple, possibly disconnected, d-sheeted branched covering π of a closed 2-dimensional disk D by a surface X. The isotopy classes of homeomorphisms of D which are pointwise fixed on the boundary of D and permute the branch values, form the braid group Bₙ, where n is the number of branch values. Some of these homeomorphisms can be lifted to homeomorphisms of X which fix pointwise the fiber over the base point. They form a subgroup of finite index in Bₙ. For each equivalence class...
L'image d'un groupe dans un groupe hyperbolique.