Des groupes magiques ou quand des sous-groupes libres affines opèrent proprement discontinûment sur
Distortion in transformation groups (with an appendix by Yves de Cornulier).
Edge-transitive maps and non-orientable surfaces
Equivariant outer space and automorphisms of free-by-finite groups.
Finite group actions on acyclic -complexes
Finite subset spaces of graphs and punctured surfaces.
Fixed point data of finite groups acting on 3-manifolds.
Geography of symplectic 4-manifolds with Kodaira dimension one.
Geometric subgroups of surface braid groups
Let be a surface, let be a subsurface, and let be two positive integers. The inclusion of in gives rise to a homomorphism from the braid group with strings on to the braid group with strings on . We first determine necessary and sufficient conditions that this homomorphism is injective, and we characterize the commensurator, the normalizer and the centralizer of in . Then we calculate the commensurator, the normalizer and the centralizer of in for large surface braid...
Géométries modèles de dimension trois
On expose une preuve détaillée de la classification par Thurston des huit géométries modèles de dimension trois.
Geometry and topology of -covered foliations.
Global rigidity of solvable group actions on .
Hyperbolic cone-manifolds with large cone-angles.
Involutions of 3-dimensional handlebodies
We study the orientation preserving involutions of the orientable 3-dimensional handlebody , for any genus g. A complete classification of such involutions is given in terms of their fixed points.
Isolated fixed points of circle actions on 4-manifolds.
Kleinian groups and the rank problem.
La trace du noyau de la chaleur des variétés hyperboliques de dimension 3
Mapping class group of a handlebody
Let B be a 3-dimensional handlebody of genus g. Let ℳ be the group of the isotopy classes of orientation preserving homeomorphisms of B. We construct a 2-dimensional simplicial complex X, connected and simply-connected, on which ℳ acts by simplicial transformations and has only a finite number of orbits. From this action we derive an explicit finite presentation of ℳ.
Maximal actions of finite 2-groups on ℤ₂-homology 3-spheres
It is known that a finite 2-group acting on a ℤ₂-homology 3-sphere has at most ten conjugacy classes of involutions; the action of groups with the maximal number of conjugacy classes of involutions is strictly related to some questions concerning the representation of hyperbolic 3-manifolds as 2-fold branched coverings of knots. Using a low-dimensional approach we classify these maximal actions both from an algebraic and from a geometrical point of view.
Measured foliations and mapping class groups of surfaces.