scholarly journals Direct Method and Approximation of the Reciprocal Difference Functional Equations in Various Normed Spaces

2015 ◽  
Vol 0 (0) ◽  
Author(s):  
H. Azadi Kenary
Keyword(s):  
Functional Equations ◽  
Direct Method ◽  
Normed Spaces ◽  
Reciprocal Difference ◽  
Rassias Stability

AbstractIn this paper, using direct method, we prove the generalized Hyers- Ulam-Rassias stability of the reciprocal difference functional equations in various normed spaces.

scholarly journals On new stability results for composite functional equations in quasi-β-normed spaces

2021 ◽  
Vol 54 (1) ◽  
pp. 68-84
Author(s):  
Anurak Thanyacharoen ◽  
Wutiphol Sintunavarat
Keyword(s):  
Banach Space ◽  
Functional Equation ◽  
Functional Equations ◽  
Direct Method ◽  
Functional Inequality ◽  
Fixed Point Method ◽  
Normed Spaces ◽  
Composite Functional Equations ◽  
Stability Results ◽  
Rassias Stability

Abstract In this article, we prove the generalized Hyers-Ulam-Rassias stability for the following composite functional equation: f ( f ( x ) − f ( y ) ) = f ( x + y ) + f ( x − y ) − f ( x ) − f ( y ) , f(f\left(x)-f(y))=f\left(x+y)+f\left(x-y)-f\left(x)-f(y), where f f maps from a ( β , p ) \left(\beta ,p) -Banach space into itself, by using the fixed point method and the direct method. Also, the generalized Hyers-Ulam-Rassias stability for the composite s s -functional inequality is discussed via our results.

scholarly journals Hyers–Ulam–Rassias Stability of Additive Mappings in Fuzzy Normed Spaces

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Jianrong Wu ◽  
Lingxiao Lu
Keyword(s):  
Functional Equations ◽  
Normed Spaces ◽  
Additive Mappings ◽  
Rassias Stability

In this paper, the Hyers–Ulam–Rassias stabilities of two functional equations, f a x + b y = r f x + s f y and f x + y + z = 2 f x + y / 2 + f z , are investigated in the framework of fuzzy normed spaces.

scholarly journals Solution and Hyers-Ulam-Rassias Stability of Generalized Mixed Type Additive-Quadratic Functional Equations in Fuzzy Banach Spaces

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
M. Eshaghi Gordji ◽  
H. Azadi Kenary ◽  
H. Rezaei ◽  
Y. W. Lee ◽  
G. H. Kim
Keyword(s):  
Functional Equation ◽  
Fixed Point ◽  
Banach Spaces ◽  
Functional Equations ◽  
Mixed Type ◽  
Direct Method ◽  
Quadratic Functional ◽  
Ulam Stability ◽  
Fixed Point Methods ◽  
Rassias Stability

By using fixed point methods and direct method, we establish the generalized Hyers-Ulam stability of the following additive-quadratic functional equationf(x+ky)+f(x−ky)=f(x+y)+f(x−y)+(2(k+1)/k)f(ky)−2(k+1)f(y)for fixed integerskwithk≠0,±1in fuzzy Banach spaces.

scholarly journals A General System of Euler–Lagrange-Type Quadratic Functional Equations in Menger Probabilistic Non-Archimedean 2-Normed Spaces

2011 ◽  
Vol 2011 ◽  
pp. 1-21 ◽  
Author(s):  
M. Eshaghi Gordji ◽  
M. B. Ghaemi ◽  
Y. J. Cho ◽  
H. Majani
Keyword(s):  
Functional Equations ◽  
General System ◽  
Quadratic Functional ◽  
Normed Spaces ◽  
Rassias Stability

We prove the generalized Hyers-Ulam-Rassias stability of a general system of Euler-Lagrange-type quadratic functional equations in non-Archimedean 2-normed spaces and Menger probabilistic non-Archimedean-normed spaces.

scholarly journals Ulam Stability of a Functional Equation in Various Normed Spaces

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1119
Author(s):  
Krzysztof Ciepliński
Keyword(s):  
Functional Equation ◽  
Banach Spaces ◽  
Functional Equations ◽  
Direct Method ◽  
Ulam Stability ◽  
Normed Spaces ◽  
Quadratic Mappings ◽  
The Stability

In this note, we study the Ulam stability of a general functional equation in four variables. Since its particular case is a known equation characterizing the so-called bi-quadratic mappings (i.e., mappings which are quadratic in each of their both arguments), we get in consequence its stability, too. We deal with the stability of the considered functional equations not only in classical Banach spaces, but also in 2-Banach and complete non-Archimedean normed spaces. To obtain our outcomes, the direct method is applied.

scholarly journals Stability of an AQCQ functional equation in non-Archimedean (n, β)-normed spaces

2019 ◽  
Vol 52 (1) ◽  
pp. 130-146
Author(s):  
Yachai Liu ◽  
Xiuzhong Yang ◽  
Guofen Liu
Keyword(s):  
Functional Equation ◽  
Direct Method ◽  
Normed Spaces ◽  
Quartic Functional Equation ◽  
Rassias Stability

AbstractIn this paper, we adopt direct method to prove the Hyers-Ulam-Rassias stability of an additivequadratic-cubic-quartic functional equation$$f(x + 2y) + f(x - 2y) = 4f(x + y) + 4f(x - y) - 6f(x) + f(2y) + f( - 2y) - 4f(y) - 4f( - y)$$in non-Archimedean (n, β)-normed spaces.

scholarly journals Fuzzy Stability Results of Generalized Quartic Functional Equations

Mathematics ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 120
Author(s):  
Sang Og Kim ◽  
Kandhasamy Tamilvanan
Keyword(s):  
Functional Equation ◽  
Functional Equations ◽  
Control Function ◽  
Direct Method ◽  
Normed Spaces ◽  
Quartic Functional Equation ◽  
New Type ◽  
The Stability ◽  
Fixed Point Techniques ◽  
Stability Results

In the present paper, we introduce a new type of quartic functional equation and examine the Hyers–Ulam stability in fuzzy normed spaces by employing the direct method and fixed point techniques. We provide some applications in which the stability of this quartic functional equation can be controlled by sums and products of powers of norms. In particular, we show that if the control function is the fuzzy norm of the product of powers of norms, the quartic functional equation is hyperstable.

scholarly journals On the stability of the quadratic mapping in normed spaces

2001 ◽  
Vol 25 (4) ◽  
pp. 217-229 ◽  
Author(s):  
Gwang Hui Kim
Keyword(s):  
Functional Equations ◽  
Quadratic Functional ◽  
Quadratic Mapping ◽  
Ulam Stability ◽  
Normed Spaces ◽  
The Stability ◽  
Rassias Stability

The Hyers-Ulam stability, the Hyers-Ulam-Rassias stability, and also the stability in the spirit of Gavruţa for each of the following quadratic functional equationsf(x+y)+f(x−y)=2f(x)+2f(y),f(x+y+z)+f(x−y)+f(y−z)+f(z−x)=3f(x)+3f(y)+3f(z),f(x+y+z)+f(x)+f(y)+f(z)=f(x+y)+f(y+z)+f(z+x)are investigated.

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