Cohomology of congruence subgroups of SL(4,Z)

Avner Ash, Paul E. Gunnells, Mark McConnell

Let $N>1$ be an integer, and let $Γ= Γ_0 (N) \subset \SL_4 (\Z)$ be the subgroup of matrices with bottom row congruent to $(0,0,0,\ast )\mathrm{mod}N$. We compute $H^5 (Γ; \C) $ for a range o…