Ein Freiheitskriterium für pro-p-Gruppen mit Anwendung auf die Struktur der Brauer-Gruppe.
Equivariant outer space and automorphisms of free-by-finite groups.
Erratum: J. Eur. Math. Soc. 1, 199-235 (1999)
Erratum to: Homology stability for outer automorphism groups of free groups.
Estimates for homological dimension of configuration spaces of graphs
We show that the homological dimension of a configuration space of a graph Γ is estimated from above by the number b of vertices in Γ whose valence is greater than 2. We show that this estimate is optimal for the n-point configuration space of Γ if n ≥ 2b.
Euler Characteristic and Characters of Discrete Groups.
Euler Characteristics of Discrete Groups and G-Spaces.
Euler Characteristics of Groups: The p-Fractional Part.
Every Finite Complex has the Homology of a Duality Group.
Explicit resolutions for the binary polyhedral groups and for other central extensions of the triangle gorups.
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....
Extension theories for monoids.
Extensions realising a faithful abstract kernel and their automorphisms.