Coverings of stably parallelizable manifolds
Croissance uniforme dans les groupes hyperboliques
On montre qu’un groupe hyperbolique non élémentaire est à croissance uniformément exponentielle, c’est-à-dire qu’il existe une constante strictement plus grande que 1, ne dépendant que du groupe , telle que le taux de croissance exponentiel de relatif à n’importe quel système générateur est plus grand que . On redémontre ce faisant qu’un groupe hyperbolique n’a qu’un nombre fini de classes de conjugaison de sous-groupes finis.
Cross ratios, surface groups, and diffeomorphisms of the circle
This article relates representations of surface groups to cross ratios. We first identify a connected component of the space of representations into PSL(n,ℝ) – known as the n-Hitchin component– to a subset of the set of cross ratios on the boundary at infinity of the group. Similarly, we study some representations into associated to cross ratios and exhibit a “character variety” of these representations. We show that this character variety contains alln-Hitchin components as well as the set of...
Crosscaps and knots.
Crystallizations of generalized Neuwirth manifolds.
Curvature testing in 3-dimensional metric polyhedral complexes.
Cusp structures of alternating links.
Cyclic actions on - and -bundles over
Cyclic branched coverings and homology 3-spheres with large group actions
We show that, if the covering involution of a 3-manifold M occurring as the 2-fold branched covering of a knot in the 3-sphere is contained in a finite nonabelian simple group G of diffeomorphisms of M, then M is a homology 3-sphere and G isomorphic to the alternating or dodecahedral group 𝔸₅ ≅ PSL(2,5). An example of such a 3-manifold is the spherical Poincaré sphere. We construct hyperbolic analogues of the Poincaré sphere. We also give examples of hyperbolic ℤ₂-homology 3-spheres with PSL(2,q)-actions,...
Cyclic branched coverings of 2-bridge knots.
In this paper we study the connections between cyclic presentations of groups and the fundamental group of cyclic branched coverings of 2-bridge knots. Then we show that the topology of these manifolds (and knots) arises, in a natural way, from the algebraic properties of such presentations.
Cyclic branched coverings of knots and homology spheres.
We study cyclic coverings of S3 branched over a knot, and study conditions under which the covering is a homology sphere. We show that the sequence of orders of the first homology groups for a given knot is either periodic of tends to infinity with the order of the covering, a result recently obtained independently by Riley. From our computations it follows that, if surgery on a knot k with less than 10 crossings produces a manifold with cyclic fundamental group, then k is a torus knot.
Cyclic Crystallizations of Spheres.
Cyclic projective planes and Wada dessins.
Cylinder and horoball packing in hyperbolic space.
Déchirures de variétés de dimension trois et la conjecture de Nash de rationalité en dimension trois.
Decomposition spaces having arbitrarily small neighborhoods with 2-sphere boundaries II
Decompositions of manifolds into codimension one submanifolds
Deformation and rigidity of simplicial group actions on trees.
Deformation of Maps to Branched Coverings in Dimension Three.
Deformation of string topology into homotopy skein modules.