STABILITY OF AN ADDITIVE-QUARTIC FUNCTIONAL EQUATION IN ORTHOGONALITY SPACES

Random Stability of an Additive-Quadratic-Quartic Functional Equation

1 Department of Mathematics, Islamic Azad University-Ayatollah Amoli Branch, Amol, P.O. Box 678, Iran 2 Department of Mathematics Education and the RINS, Gyeongsang National University, Chinju 660-701, South Korea 3 Department of Mathematics, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, South Korea 4 Dipartimento di Matematica ed Applicazioni, Università degli Stu...

Fuzzy Stability of an Additive-Quadratic-Quartic Functional Equation

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...

Stability of an Additive-Cubic-Quartic Functional Equation in Multi-Banach Spaces

and Applied Analysis 3 for some natural number n0. Moreover, if the second alternative holds, then i the sequence {Jnx} is convergent to a fixed point y∗ of J ; ii y∗ is the unique fixed point of J in the set Y : {y ∈ X | d J0x, y < ∞} and d y, y∗ ≤ 1/ 1 − L d y, Jy , for all , x, y ∈ Y . Following 30, 31 , we recall some basic facts concerning multi-normed spaces and some preliminary results. ...

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.

On the Stability of the Orthogonally Quartic Functional Equation