Multi-Jensen and multi-Euler-Lagrange additive mappings (Q6617101)

The authors introduce new definitions of multi-variable versions of the classical Jensen and Euler-Lagrange functional equations (called multi-Jensen and multi-Euler-Lagrange). Some characterizations of these mappings are presented and, in the final part of the paper, their stability (in sense of Hyers-Ulam and generalized) is considered.