34 citations · 89 across the 16 of their papers we have counts for
6 papers · 1 filter
Accessing the cohomology of discrete groups above their virtual cohomological dimension
Alexander D. Rahm
We introduce a method to explicitly determine the Farrell-Tate cohomology of discrete groups. We apply this method to the Coxeter triangle and tetrahedral groups as well as to the…
On Ruan's Cohomological Crepant Resolution Conjecture for the complexified Bianchi orbifolds
Fabio Perroni, Alexander Rahm
We give formulae for the Chen-Ruan orbifold cohomology for the orbifolds given by a Bianchi group acting on complex hyperbolic 3-space. The Bianchi groups are the arithmetic groups…
The homological torsion of PSL_2 of the imaginary quadratic integers
Alexander Rahm
Denote by Q(sqrt{-m}), with m a square-free positive integer, an imaginary quadratic number field, and by A its ring of integers. The Bianchi groups are the groups SL_2(A). We reve…
Complexifiable characteristic classes
Alexander D. Rahm
We examine the topological characteristic cohomology classes of complexified vector bundles. In particular, all the classes coming from the real vector bundles underlying the compl…
Homology and K-theory of the Bianchi groups
Alexander D. Rahm
We reveal a correspondence between the homological torsion of the Bianchi groups and new geometric invariants, which are effectively computable thanks to their action on hyperbolic…
On Level One Cuspidal Bianchi Modular Forms
Alexander D. Rahm, Mehmet Haluk Sengun
In this paper, we present the outcome of vast computer calculations, locating several of the very rare instances of level one cuspidal Bianchi modular forms that are not lifts of e…