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...

In this paper, the gradual real numbers are considered and the notion of the gradual normed linear space is given. Also some topological properties of such spaces are studied, and it is shown that the gradual normed linear space is a locally convex space, in classical sense. So the results in locally convex spaces can be translated in gradual normed linear spaces. Finally, we give an examp...

 The concept of statistical convergence in $2$-normed spaces for double sequence was introduced in [S. Sarabadan and S. Talebi, {it Statistical convergence of double sequences  in $2$-normed spaces }, Int. J. Contemp. Math. Sci. 6 (2011) 373--380]. In the first, we introduce concept strongly statistical convergence in $2$-normed spaces and generalize some results. Moreover,  we define the conce...

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...

In this paper, we study the concept of t-best coapproximation in fuzzy anti-2-normed linear spaces. We introduce the notion of t-best coapproximation, t-coproximinal sets, t-coChebyshev sets and t-orthogonality and prove some interesting theorems to characterization of t-best coapproximation elements. AMS subject classification: 46S40, 41A50.

the concept of statistical convergence in 2-normed spaces fordouble sequence was introduced in [17]. in the first, we introduceconcept strongly statistical convergence in $2$- normed spaces andgeneralize some results. moreover,  we define the concept of statisticaluniform convergence in $2$- normed spaces and prove a basictheorem of uniform convergence in double sequences to the case ofstatisti...

In this paper, we prove the generalized Hyres–Ulam–Rassias stability of the mixed type cubic and quartic functional equation f (x + 2y) + f (x − 2y) = 4(f (x + y) + f (x − y)) − 24f (y) − 6f (x) + 3f (2y) in non-Archimedean ℓ-fuzzy normed spaces.

In this paper, we obtain the general solution and investigate the Hyers-Ulam-Rassias stability of the functional equation f(ax− y)± af(x± y) = (a± 1)[af(x)± f(y)] in non-Archimedean -fuzzy normed spaces. Mathematics Subject Classification: 39B55, 39B52, 39B82