A family of 4-branch-point covers with monodromy group PSL(6,2)

Abstract

We describe the explicit computation of a family of 4-branch-point rational functions of degree 63 with monodromy group PSL(6,2). This, in particular, negatively answers a question by J. K\"onig whether there exists a such a function with rational coefficients. The computed family also gives rise to non-regular degree-126 realizations of Aut(PSL(6,2)) over Q(t).