On an equation characterizing multi-Jensen-quadratic mappings and its Hyers-Ulam stability via a fixed point method
A mapping \(f: G^n\to H\) is called multi-Jensen-quadratic if it satisfies the Jensen equation on some fixed variables and the Jordan-von Neumann equation on the remaining ones (i.e., it satisfies some system of functional equations). The authors introduce a single functional equation which characterizes the above mentioned class of mappings. Then, applying a fixed point technique, the Hyers-Ulam stability of this newly introduced equation is considered -- in Banach spaces as well as in complete non-Archimedean normed spaces.
scientific article; zbMATH DE number 6678393
scientific article