A Voronoi-Oppenheim summation formula for totally real number fields

Abstract

We obtain a Voronoi-Oppenheim summation formula for divisor functions of totally real number fields. This generalizes a formula proved by Oppenheim in 1927. We use a similar method to the one developed by Beineke and Bump in order to prove the classical Oppenheim summation using a certain Eisenstein series and representation theory. Our formula has a simple formulation for real quadratic number fields.