Stability of quadratic functional equations in generalized functions

Generalized Hyers–ulam Stability of Refined Quadratic Functional Equations

In this paper, we give a general solution of a refined quadratic functional equation and then investigate its generalized Hyers–Ulam stability in quasi-normed spaces and in non-Archimedean normed spaces. AMS Subject Classification: 39B82, 39B62

Stability of Trigonometric Functional Equations in Generalized Functions

Quadratic $alpha$-functional equations

In this paper, we solve the quadratic $alpha$-functional equations $2f(x) + 2f(y) = f(x + y) + alpha^{-2}f(alpha(x-y)); (0.1)$ where $alpha$ is a fixed non-Archimedean number with $alpha^{-2}neq 3$. Using the fixed point method and the direct method, we prove the Hyers-Ulam stability of the quadratic $alpha$-functional equation (0.1) in non-Archimedean Banach spaces.

Fuzzy Stability of Quadratic Functional Equations

Katsaras 1 defined a fuzzy norm on a vector space to construct a fuzzy vector topological structure on the space. Some mathematicians have defined fuzzy norms on a vector space from various points of view 2–4 . In particular, Bag and Samanta 5 , following Cheng and Mordeson 6 , gave an idea of fuzzy norm in such a manner that the corresponding fuzzy metric is of Kramosil and Michálek type 7 . T...

Fuzzy Stability of Additive–quadratic Functional Equations

In this paper we investigate the generalized HyersUlam stability of the functional equation f(2x + y) + f(2x − y) = f(x + y) + f(x − y) + 2f(2x)− 2f(x) in fuzzy Banach spaces.