On decomposition of 3-polyhedra into a Cartesian product
On deformations of hyperbolic 3-manifolds with geodesic boundary.
On diffeomorphisms over surfaces trivially embedded in the 4-sphere.
On Dihedral Covering Spaces of Knots.
On Embedded Spheres in 3-manifolds.
On equivariant deformations of maps.
We work in the smooth category: manifolds and maps are meant to be smooth. Let G be a finite group acting on a connected closed manifold X and f an equivariant self-map on X with f|A fixpointfree, where A is a closed invariant submanifold of X with codim A ≥ 3. The purpose of this paper is to give a proof using obstruction theory of the following fact: If X is simply connected and the action of G on X - A is free, then f is equivariantly deformable rel. A to fixed point free map if and only if the...
On finite groups acting on a connected sum of 3-manifolds S² × S¹
Let denote the closed 3-manifold obtained as the connected sum of g copies of S² × S¹, with free fundamental group of rank g. We prove that, for a finite group G acting on which induces a faithful action on the fundamental group, there is an upper bound for the order of G which is quadratic in g, but there does not exist a linear bound in g. This implies then a Jordan-type bound for arbitrary finite group actions on which is quadratic in g. For the proofs we develop a calculus for finite group...
On finite groups acting on acyclic low-dimensional manifolds
We consider finite groups which admit a faithful, smooth action on an acyclic manifold of dimension three, four or five (e.g. Euclidean space). Our first main result states that a finite group acting on an acyclic 3- or 4-manifold is isomorphic to a subgroup of the orthogonal group O(3) or O(4), respectively. The analogous statement remains open in dimension five (where it is not true for arbitrary continuous actions, however). We prove that the only finite nonabelian simple groups admitting a smooth...
On finite subgroups of groups of type VF.
On Fox's theory of overlays
On framed links of Peiffer identities
On general dissections of a polygon.
On general dissections of a polygon. (Short Communication).
On groups generated by two positive multi-twists: Teichmüller curves and Lehmer's number.
On groups with linear sci growth
We prove that the semistability growth of hyperbolic groups is linear, which implies that hyperbolic groups which are sci (simply connected at infinity) have linear sci growth. Based on the linearity of the end-depth of finitely presented groups we show that the linear sci is preserved under amalgamated products over finitely generated one-ended groups. Eventually one proves that most non-uniform lattices have linear sci.
On Heegaard Decompositions of Torus Knot Exteriors and Related Seifert Fibre Spaces.
On homotopy types of 2-dimensional polyhedra
On hyperbolic 3-manifolds obtained by Dehn surgery on links.
On hyperbolic 3-manifolds realizing the maximal distance between toroidal Dehn fillings.
On irreducible, infinite, nonaffine Coxeter groups
The following results are proved: The center of any finite index subgroup of an irreducible, infinite, nonaffine Coxeter group is trivial; Any finite index subgroup of an irreducible, infinite, nonaffine Coxeter group cannot be expressed as a product of two nontrivial subgroups. These two theorems imply a unique decomposition theorem for a class of Coxeter groups. We also prove that the orbit of each element other than the identity under the conjugation action in an irreducible, infinite, nonaffine...