On subgroups of the Monster isomorphic to $PSL_2(8)$

Abstract

We describe computer calculations that were used in 2016 to classify subgroups of the Monster isomorphic to $PSL_2(8)$, containing $7B$-elements. It turns out that there is no such $PSL_2(8)$ in the Monster. These calculations confirm earlier unpublished calculations by P. E. Holmes that obtained the same result. The result has also been confirmed in independent calculations by H. Dietrich, M. Lee and T. Popiel, using different software by M. Seysen. Thus this experimental result is shown to be reproducible.