Tame torsion and the tame inverse Galois problem

Abstract

Fix a positive integer g and a squarefree integer m. We prove the existence of a genus g curve C/{mathbb {Q}} such that the mod m representation of its Jacobian is tame. The method is to analyse the period matrices of hyperelliptic Mumford curves, which could be of independent interest. As an application, we study the tame version of the inverse Galois problem for symplectic matrix groups over finite fields.