We apply the Radu–Miheţ method derived from an alternative fixed-point theorem with a class of matrix-valued fuzzy controllers to approximate fractional Volterra integro-differential equation ψ-Hilfer derivative in k-normed spaces obtain approximation for this type equation.

Notions of betweenness and indiguishability play important roles in the problems of pattern recognition, process identi cation and modelling based on metric spaces machinery. The situation complicates if these two concepts should be applied in real world when a system designer is always confronted with uncertainty about systems and signals. To overcome at least a part of di culties the authors ...

The object of this paper is to introduce the notion of intuitionisticfuzzy continuous mappings and intuitionistic fuzzy bounded linear operatorsfrom one intuitionistic fuzzy n-normed linear space to another. Relation betweenintuitionistic fuzzy continuity and intuitionistic fuzzy bounded linearoperators are studied and some interesting results are obtained.

In this paper, we determine some stability results concerning the 2-dimensional vector variable quadratic functional equation f(x+ y, z + w) + f(x − y, z − w) = 2f(x, z) + 2f(y, w) in intuitionistic fuzzy normed spaces (IFNS). We define the intuitionistic fuzzy continuity of the 2-dimensional vector variable quadratic mappings and prove that the existence of a solution for any approximately 2-d...

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...