A fixed point approach to the stability of additive-quadratic-quartic functional equations

A Fixed Point Approach to the Stability of an Additive-Quadratic-Cubic-Quartic Functional Equation

The stability problem of functional equations is originated from a question of Ulam 1 concerning the stability of group homomorphisms. Hyers 2 gave a first affirmative partial answer to the question of Ulam for Banach spaces. Hyers’ Theorem was generalized by Aoki 3 for additive mappings and by Th. M. Rassias 4 for linear mappings by considering an unbounded Cauchy difference. The paper of Th. ...

A FIXED POINT APPROACH TO THE INTUITIONISTIC FUZZY STABILITY OF QUINTIC AND SEXTIC FUNCTIONAL EQUATIONS

The fixed point alternative methods are implemented to giveHyers-Ulam  stability for  the quintic functional equation $ f(x+3y)- 5f(x+2y) + 10 f(x+y)- 10f(x)+ 5f(x-y) - f(x-2y) = 120f(y)$ and thesextic functional equation $f(x+3y) - 6f(x+2y) + 15 f(x+y)- 20f(x)+15f(x-y) - 6f(x-2y)+f(x-3y) = 720f(y)$   in the setting ofintuitionistic fuzzy normed spaces (IFN-spaces).  This methodintroduces a met...

A Fixed Point Approach to the Stability of a Mixed Type Additive and Quadratic Functional Equation

In this paper, we investigate the stability problems for a functional equation f(ax + y) + af(x − y) − a2+3a 2 f(x) −a(a−1) 2 f(−x)− f(y) − af(−y) = 0 by using the fixed point method. Mathematics Subject Classification: Primary 39B82, 39B62; Secondary 47H10

A Fixed Point Approach to the Stability of the Cauchy Additive and Quadratic Type 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.

A Fixed Point Approach to the Fuzzy Stability of an Additive-Quadratic-Cubic 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...