On -deficiency in groups
arXiv:1106.3255 · doi:10.1515/jgt-2013-0003
Abstract
Recently, Schlage-Puchta proved super multiplicity of -deficiency for normal subgroups of -power index. We extend this result to all normal subgroups of finite index. We then use the methods of the proof to show that some groups with non-positive -deficiency have virtually positive -deficiency. We also compute the -deficiency in some cases such as Fuchsian groups and study related invariants: the lower and upper absolute -homology gradients and the -Euler characteristic.
The abstract and introduction were comletely rewritten. Further minor changes were made for the rest of the paper