Alternative jensen functional equation on groups

Abstract

Given integers α, β, γ such that (α, β, γ) ̸= k(1,−2, 1) for all k ∈ Z, we will establish a criterion for the existence of the general solution of the alternative Jensen functional equation of the form f(xy^{−1}) − 2f(x) + f(xy) = 0 or αf(xy^{−1}) + βf(x) + γf(xy) = 0, where f is a mapping from a group (G, ·) to a uniquely divisible abelian group (H, +).