Corrigendum to: "Aspherical four-manifolds and the centres of two-knot groups".
Das Nielsensche Realisierungsproblem für hinreichend große 3-Mannigfaltigkeiten.
Decomposition Theorems for Group Pairs.
Die Unterscheidung von Homotopietyp und einfachem Homotopietyp bei zweidimensionalen Komplexen.
Embeddings of graph braid and surface groups in right-angled Artin groups and braid groups.
Explicit presentations for exceptional braid groups.
Extension of complexes of groups
Complexes of groups over ordered simplicial complexes are generalizations to higher dimensions of graphs of groups. We first relate them to complexes of spaces by considering their classifying space . Then we develop their homological algebra aspects. We define the notions of homology and cohomology of a complex of groups with coefficients in a -module and show the existence of free resolutions. We apply those notions to study extensions of complexes of groups with constant or abelian kernel....
Extensions realising a faithful abstract kernel and their automorphisms.
Faithful integral and modular representations of the Klein bottle group
Families of jacobian manifolds and characteristic classes of surface bundles. I
In our previous work we have defined the notion of characteristic classes of surface bundles, which are differentiable fibre bundles whose fibres are closed oriented surfaces. In this paper we derive new relations between these characteristic classes by considering a canonical embedding of a given surface bundle with cross section to its associated family of Jacobian manifolds. As a key technical step we determine the first cohomology group of the mapping class group of oriented surfaces with coefficients...
Farrell cohomology of low genus pure mapping class groups with punctures.
Finitely Presented Subgroups of Three-Manifold Groups.
Folding on the wedge sum of graphs and their fundamental group.
Formal language theory and the geometry of 3-manifolds.
Fox pairings and generalized Dehn twists
We introduce a notion of a Fox pairing in a group algebra and use Fox pairings to define automorphisms of the Malcev completions of groups. These automorphisms generalize to the algebraic setting the action of the Dehn twists in the group algebras of the fundamental groups of surfaces. This work is inspired by the Kawazumi–Kuno generalization of the Dehn twists to non-simple closed curves on surfaces.
Framed Links for Pfeiffer Identities.
Free and non-free subgroups of the fundamental group of the Hawaiian Earrings
The space which is composed by embedding countably many circles in such a way into the plane that their radii are given by a null-sequence and that they all have a common tangent point is called “The Hawaiian Earrings”. The fundamental group of this space is known to be a subgroup of the inverse limit of the finitely generated free groups, and it is known to be not free. Within the recent move of trying to get hands on the algebraic invariants of non-tame (e.g. non-triangulable) spaces this space...
Free group automorphisms, invariant orderings and topological applications.
Group negative curvature for 3-manifolds with genuine laminations.
Groups of finite quasi-projective dimension.