On the Stability of Cubic Mappings and Quadratic Mappings in Random Normed Spaces

Abstract

Abstract Recently, the stability of the cubic functional equation in fuzzy normed spaces was proved in earlier work; and the stability of the additive functional equations , in random normed spaces was proved as well. In this paper, we prove the stability of the cubic functional equation in random normed spaces by an alternative proof which provides a better estimation. Finally, we prove the stability of the quartic functional equation in random normed spaces.