A presentation of symplectic Steinberg modules and cohomology of ${\mathrm{Sp}}_{2n}(\mathbb{Z})$

Benjamin Brück, Peter Patzt, Robin J. Sroka

Borel-Serre proved that the integral symplectic group ${\mathrm{Sp}}_{2n}(\mathbb{Z})$ is a virtual duality group of dimension $n^2$ and that the symplectic Steinberg module $\…