Finite index subgroups of mapping class groups

Luis Paris, Jon A Berrick, Volker Gebhardt

Let $g\ge 3$ and $n\ge 0$, and let ${\mathcal{M}}_{g,n}$ be the mapping class group of a surface of genus $g$ with $n$ boundary components. We prove that ${\mathcal{M}}_{g,n}$ cont…