Résumé
We recall the relation between Zeta function representation of groups and two-dimensional topological Yang-Mills theory through Mednikh formula. We prove various generalisations of Mednikh formulas and define generalization of Zeta functions representations of groups. We compute some of these functions in the case of the finite group$GL(2, {\mathbb F}_q)$and$PGL(2,{\mathbb F}_q).$We recall the table characters of these groups for any$q$ , compute the Frobenius-Schur indicator of their irreducible representations and give the explicit structure of their fusion rings