Hopf algebras in the cohomology of ${\mathcal{A}}_g$, ${\mathrm{GL}}_n(\mathbb{Z})$, and ${\mathrm{SL}}_n(\mathbb{Z})$

Francis Brown, Melody Chan, Søren Galatius +1

We describe a bigraded cocommutative Hopf algebra structure on the weight zero compactly supported rational cohomology of the moduli space of principally polarized abelian varietie…