Multivariable mappings associated with the Drygas functional equation and a fixed point approach
摘要
In the current study, we represent a multi-Drygas mapping (defined by EL-Fassi et al. as a system of the multi-Drygas functional equations) as an equation. We also portray that a multi-Drygas mapping under odd or even condition in each variable can be reduced to multi-Jensen, multi-quadratic and multi-Jensen-quadratic. Moreover, we prove the Găvruţa and Hyers stability (without zero condition) of the multi-Drygas mappings via a known fixed point approach due to Brzdȩk. These results show that we can remove the condition zero condition which is applied in the work of Dehghanian et al. [