We present a novel generalization of the Hyers–Ulam–Rassias stability definition to study generalized cubic set-valued mapping in normed spaces. In order achieve our goals, we have applied brand new fixed point alternative. Meanwhile, obtained practicable example demonstrating that is not defined as stable according previously methods and procedures.

In the paper we establish the general solution of the function equation f(2x+y)+f(2x-y) = f(x+y)+f(x-y)+2f(2x)-2f(x) and investigate the Hyers-Ulam-Rassias stability of this equation in 2-Banach spaces.

In  this paper, we investigate the generalizedHyers-Ulam-Rassias stability for the quartic, cubic and additivefunctional equation$$f(x+ky)+f(x-ky)=k^2f(x+y)+k^2f(x-y)+(k^2-1)[k^2f(y)+k^2f(-y)-2f(x)]$$ ($k in mathbb{Z}-{0,pm1}$) in $p-$Banach spaces.

We present several new sufficient conditions for Hyers-Ulam and Hyers-Ulam-Rassias stability of first-order linear dynamic equations functions defined on a time scale with values in Banach space.