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The stability problem in Ulam's sense has recently been explored in locally convex cone environments, as shown in \cite{ MNF, NR1, NR2}. In continuation of this research direction, our work examines the stability properties of the quadratic…

Functional Analysis · Mathematics 2025-08-19 J. -H. Bae , J. Mohammadpour , A. Najati

In this paper, we discuss the Hyers-Ulam stability of mixed-type additive-cubic Jensen functional equation \begin{align*}…

Functional Analysis · Mathematics 2024-07-31 Koushika Dhevi Sankar , Sangeetha Sampath

In this paper we will investigate the solutions and stability of the generalized variant of Wilson's functional equation $$ (E):\;\;\;\; f(xy)+\chi(y)f(\sigma(y)x)=2f(x)g(y),\; x,y\in G,$$ where $G$ is a group, $\sigma$ is an involutive…

Classical Analysis and ODEs · Mathematics 2015-05-26 Elqorachi Elhoucien , Redouani Ahmed

In this paper we establish the stability of the functional equation $$f(x-y)=f(x)g(y)+g(x)f(y)+h(x)h(y)),\;\; x,y \in G, $$where $G$ is an abelian group.

Commutative Algebra · Mathematics 2018-10-25 Ajebbar Omar , Elqorachi Elhoucien , Themistocles M. Rassias

Using the direct method, we prove the generalised Hyers-Ulam stability of the following functional equation \begin{equation} \phi(x+y, z+w)+\phi(x-y, z-w)-2 \phi(x, z)-2 \phi(x, w)=0 \end{equation} in modular space satisfying the Fatou…

General Mathematics · Mathematics 2024-06-25 Abderrahman Baza , Mohamed Rossafi , Choonkil Park

In this paper, by using the orthogonally fixed point method, we prove the Hyers-Ulam stability and the hyperstability of orthogonally 3-Lie homomorphisms for additive $\rho$-functional equation in 3-Lie algebras.\\ Indeed, we investigate…

Functional Analysis · Mathematics 2020-02-18 Vahid Keshavarz , Sedigheh Jahedi , Themistocles M. Rassias

In this paper, we introduce $n$-variables mappings which are cubic in each variable. We show that such mappings satisfy a functional equation. The main purpose is to extend the applications of a fixed point method to establish the…

Functional Analysis · Mathematics 2019-07-29 Abasalt Bodaghi , Behrouz Shojaee

In this paper we obtain a result on Hyers-Ulam stability of the linear functional equation in a single variable $f(\varphi(x)) = g(x) \cdot f(x)$ on a complete metric group.

Functional Analysis · Mathematics 2015-12-16 Soon-Mo Jung , Dorian Popa , Michael Th. Rassias

In this paper, we investigate some hyperstability results, inspired by the concept of Ulam stability, for the following functional equations: \begin{equation} \varphi(x+y)+\varphi(x-y)=2\varphi(x)+2\varphi(y) \end{equation} \begin{equation}…

Functional Analysis · Mathematics 2024-10-15 Abderrahman Baza , Mohamed Rossafi , Mohammed Mouniane

Using the fixed point alternative theorem we establish the orthogonal stability of quadratic functional equation of Pexider type $f(x+y)+g(x-y)=h(x)+k(y)$, where $f, g, h, k$ are mappings from a symmetric orthogonality space to a Banach…

Functional Analysis · Mathematics 2021-07-23 M. Mirzavaziri , M. S. Moslehian

We consider Hyers-Ulam stability of a functional equation for continuous functions on a space on which a topological group acts, analogous to the additive functional equation on a group. We show, among other things, that our generalized…

Functional Analysis · Mathematics 2015-10-08 Maysam Maysami Sadr

In this paper we establish the stability of the functional equation \begin{equation*}f(xy)=f(x)g(y)+g(x)f(y)+h(x)h(y),\;x,y\in G,\end{equation*} where $G$ is an amenable group.

Rings and Algebras · Mathematics 2018-09-20 Ajebbar Omar , Elqorachi Elhoucien

Hyre-Ulam stability of functional equation in single variable is studied in non-triangular metric spaces. We derive it as applications of some fixed point results developed on the said structure. A general version of Baker's theorem is also…

Functional Analysis · Mathematics 2024-05-22 Supriti Laha , Lakshmi Kanta Dey

Using fixed point methods, we prove the generalized Hyers--Ulam--Rassias stability of ternary homomorphisms, and ternary multipliers in ternary Banach algebras for the Jensen--type functional equation…

Functional Analysis · Mathematics 2009-12-21 A. Ebadian , Sh. Najafzadeh

In this paper we introduce ternary modules over ternary algebras and using fixed point methods, we prove the stability and super-stability of ternary additive, quadratic, cubic and quartic derivations and $\sigma$-homomorphisms in such…

Functional Analysis · Mathematics 2015-06-09 A. G. Ghazanfari , Z. Alizadeh

This paper examines various aspects related to the Cauchy functional equation $f(x+y)=f(x)+f(y)$, a fundamental equation in the theory of functional equations. In particular, it considers its solvability and its stability relative to…

Classical Analysis and ODEs · Mathematics 2017-04-26 Daniel Reem

In this paper, we give a proof of the Hyers-Ulam stability of the Jensen functional equation $$f(xy)+f(x\sigma(y))=2f(x),\phantom{+} x,y\in{G},$$ where $G$ is an amenable semigroup and $\sigma$ is an involution of $G.$

Functional Analysis · Mathematics 2014-06-17 Bouikhalene Belaid , Elqorachi Elhoucien

In \cite{bbb} the authors obtained the Hyers-Ulam stability of the functional equation $$ \int_{K}\int_{G} f(xtk\cdot y)d\mu(t)dk=f(x)g(y), \; x, y \in G ,$$ where $G$ is a Hausdorff locally compact topological group, $K$ is a copmact…

Functional Analysis · Mathematics 2014-04-17 Belaid Bouikhalene , Eloqrachi Elhoucien

In this paper, we establish the conditional Hyers-Ulam-Rassias stability of the generalized Jensen functional equation $r f \left (\frac{sx+ty}{r}) = s g(x) + t h(y)$ on various restricted domains such as inside balls, outside balls, and…

Functional Analysis · Mathematics 2021-07-23 Soon-Mo Jung , Mohammad Sal Moslehian , Prasanna K. Sahoo

This paper explores the Hyers-Ulam stability of generalized Jensen additive and quadratic functional equations in \(\beta\)-homogeneous \(F\)-space, showing that approximately satisfying mappings have a unique exact approximating…

Functional Analysis · Mathematics 2025-08-15 Jing Zhang , Qi Liu , Yongmo Hu , Linlin Fu , Yuxin Wang , Jinyu Xia , John Michael Rassias , Choonkil Park , Yongjin Li