On an equation characterizing multi-Jensen-quadratic mappings and its Hyers–Ulam stability via a fixed point method

Abstract

Abstract. In this paper, we unify the system of functional equations defining a multi-Jensen-quadratic mapping to obtain a single equation. We also prove, using the fixed point method, the generalized HyersUlam stability of this equation both in Banach spaces and in complete non-Archimedean normed spaces.Mathematics Subject Classification. 39B52, 39B72, 39B82, 47H10.