Torsion homology growth for noncongruence subgroups of Bianchi groups

Abstract

We carry out numerical experiments to investigate the growth of torsion in their first homology of noncongruence subgroups of Bianchi groups. The data we collect suggest that the torsion homology growth conjecture of Bergeron and Venkatesh for congruence subgroups may apply to the noncongruence case as well.