Fixed Points and Stability of a Generalized Quadratic Functional Equation

Fixed Points and Stability of a Generalized Quadratic Functional Equation

Intuitionistic fuzzy stability of a quadratic and quartic functional equation

In this paper, we prove the generalized Hyers--Ulamstability of a quadratic and quartic functional equation inintuitionistic fuzzy Banach spaces.

stability of the quadratic functional equation

In the present paper a solution of the generalizedquadratic functional equation$$f(kx+ y)+f(kx+sigma(y))=2k^{2}f(x)+2f(y),phantom{+} x,yin{E}$$ isgiven where $sigma$ is an involution of the normed space $E$ and$k$ is a fixed positive integer. Furthermore we investigate theHyers-Ulam-Rassias stability of the functional equation. TheHyers-Ulam stability on unbounded domains is also studied.Applic...

Fixed points and fuzzy stability of an additive-quadratic functional equation

The fuzzy stability problems for the Cauchy additive functional equation and the Jensen additive functional equation in fuzzy Banach spaces have been investigated by Moslehian et al. Using fixed point method, we prove the Hyers-Ulam stability of the functional equation

Fixed Points and Generalized Hyers–ulam Stability of Quadratic Functional Equations

Let X, Y be complex vector spaces. It is shown that if a mapping f : X → Y satisfies f (x + iy) + f (x− iy) = 2f (x) − 2f (y) (0.1) or f (x + iy) − f (ix + y) = 2f (x) − 2f (y) (0.2) for all x, y ∈ X , then the mapping f : X → Y satisfies f (x + y) + f (x− y) = 2f (x) + 2f (y) for all x, y ∈ X . Furthermore, we prove the generalized Hyers-Ulam stability of the functional equations (0.1) and (0....