Quadratic--quartic functional equations in RN--spaces

In this paper, we obtain the general solution and the stability result for the following functional equation in random normed spaces (in the sense of Sherstnev) under arbitrary $t$-norms $$f(2x+y)+f(2x-y)=4[f(x+y)+f(x-y)]+2[f(2x)-4f(x)]-6f(y).$$Comment: 11 page

Stability on Quinquevigintic Functional Equation in Different Spaces

In this work, we determine the general solution of the quinquevigintic functional equation and also investigate its stability of this equation in the setting of matrix normed spaces and the framework of matrix non-Archimedean fuzzy normed spaces by using the fixed point method

Approximation of homomorphisms and derivations of additive functional equation of n-Apollonius type in induced fuzzy Lie C*-Algebras

Using the fixed point method, we prove the generalized Hyers-Ulam stability of homomorphisms  and derivations of additive functional equation of n-Apollonius type for afixed positive n with n>=2 on induced fuzzy C*-Algebras and induced fuzzy Lie C*-Algebras

Intuitionistic fuzzy stability of a quadratic and quartic functional equation

Abstract. In this paper, we prove the generalized Hyers-Ulam stability of a quadratic and quartic functional equation in intuitionistic fuzzy Banach spaces