On the Fundamental Group of a Visibility Manifold.
On the Homeotopy Groups of Surfaces.
On the homology of the Harmonic Archipelago
We calculate the singular homology and Čech cohomology groups of the Harmonic Archipelago. As a corollary, we prove that this space is not homotopy equivalent to the Griffiths space. This is interesting in view of Eda’s proof that the first singular homology groups of these spaces are isomorphic.
On the impossibility of a generalization of the HOMFLY — Polynomial to Labelled Oriented Graphs
On the Lusternik-Schnirelmann Category of Lie Groups.
On the Lusternik-Schnirelmann Category of Lie Groups: II.
On the Malcev completion of Kähler groups.
On the residual properties of link groups.
On the Self-Equivalences of a Space with Non-cyclic Fundamental Group.
On the simple connectivity at infinity of groups
We study the simple connectivity at infinity of groups of finite presentation, and we give a geometric proof of its invariance under quasi-isometry in a special case.
On the structure of some irrotational vector fields.
Orderable 3-manifold groups
We investigate the orderability properties of fundamental groups of 3-dimensional manifolds. Many 3-manifold groups support left-invariant orderings, including all compact -irreducible manifolds with positive first Betti number. For seven of the eight geometries (excluding hyperbolic) we are able to characterize which manifolds’ groups support a left-invariant or bi-invariant ordering. We also show that manifolds modelled on these geometries have virtually bi-orderable groups. The question of virtual orderability...
Outer automorphism groups of Bieberbach groups.