Low degree bounded cohomology and <var>L</var><sup>2</sup>-invariants for negatively curved groups
Andreas ThomTechnische Universität Dresden, Germany
We study the subgroup structure of discrete groups that share cohomological properties which resemble non-negative curvature. Examples include all Gromov hyperbolic groups.
We provide strong restrictions on the possible s-normal subgroups of a ‘negatively curved’ group. Another result says that the image of a group, which is boundedly generated by a finite set of amenable subgroups, in a group, which admits a proper quasi-1-cocycle into the regular representation, has to be amenable. These results extend to a certain class of randomorphisms in the sense of Monod.
Cite this article
Andreas Thom, Low degree bounded cohomology and <var>L</var><sup>2</sup>-invariants for negatively curved groups. Groups Geom. Dyn. 3 (2009), no. 2, pp. 343–358DOI 10.4171/GGD/60