On the cohomology of SL${}_n(\mathbb{Z})$

Avner Ash

Let St denote the Steinberg module of $S{L}_n(Q)$ tensored with Q. Let Sh denote the sharbly resolution of St. By Borel-Serre duality, $H^{n(n-1)/2-i}(S{L}_n(Z),Q)$ is isomorphic to $H…