In this paper, we investigate the Hyers-Ulam stability of the orthogonally  cubic equation and  Pexiderized cubic equation [f(kx+y)+f(kx-y)=g(x+y)+g(x-y)+frac{2}{k}g(kx)-2g(x),]in multi-normed spaces by the direct method and the fixed point method. Moreover, we prove the Hyers-Ulam stability of the  $2$-variables cubic  equation [ f(2x+y,2z+t)+f(2x-y,2z-t) =2...

* Correspondence: [email protected]. kr National Institute for Mathematical Sciences, KT Daeduk 2 Research Center, 463-1 Jeonmin-dong, Yuseong-gu, Daejeon 305-811, Korea Full list of author information is available at the end of the article Abstract Lex X be a normed space and Y be a Banach fuzzy space. Let D = {(x, y) Î X × X : || x|| + ||y|| ≥ d} where d > 0. We prove that the Pexiderized Jensen...

We obtain the superstability of the Pexiderized multiplicative functional equation fxy gxhy and investigate the stability of this equation in the following form: 1/1 ψx, y ≤ fxy/gxhy ≤ 1 ψx, y.

in this paper, we investigate the generalizedhyers--ulam stability of the functional equation

We use a fixed point method to prove the Cauchy–Rassias stability of homomorphisms associated to the Pexiderized Cauchy–Jensen type functional equation r f ( x+ y r ) + sg ( x− y s ) = 2h(x), r,s ∈ R\{0}

We approximate a fuzzy almost quadratic function by a quadratic function in a fuzzy sense. More precisely, we establish a fuzzy Hyers–Ulam–Rassias stability of the quadratic functional equation f(x + y) + f(x − y) = 2f(x) + 2f(y). Our result can be regarded as a generalization of the stability phenomenon in the framework of normed spaces. We also prove a generalized version of fuzzy stability o...