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The foundation of locally convex cone theory relies on order-theoretic concepts that induce specific topological frameworks. Within this structure, cones naturally possess three distinct topologies: lower, upper, and symmetric. In this…

Functional Analysis · Mathematics 2025-04-11 Jafar Mohammadpour , Abbas Najati , Iz-iddine EL-Fassi

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

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 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

Our aim is to study the Ulam's problem for Cauchy's functional equations. First, we present some new results about the superstability and stability of Cauchy exponential functional equation and its Pexiderized for class functions on…

Classical Analysis and ODEs · Mathematics 2014-06-10 Ali Sadeghi

We show that noncommutative analog of additive functional equation has Hyers-Ulam stability on amenable discrete quantum (semi)groups. This generalizes an old classical result.

Operator Algebras · Mathematics 2015-06-23 Maysam Maysami Sadr

In this paper, we apply the publication of Joung (2009) to derive a stability result for for the second order linear functional equation: $f(x) = pf(x-1)-qf(x-2)$ for all $x\in\mathbb R$, where $f$ is a mapping from $\mathbb R$ into the…

Probability · Mathematics 2019-11-15 Mongkhon Tuntapthai

The generalized Hyers--Ulam--Rassias stability of generalized derivations on unital Banach algebras into Banach bimodules is established.

Functional Analysis · Mathematics 2021-07-23 Mohammad Sal Moslehian

In this paper, we proved the generalized Hyers-Ulam stability of homomorphisms in $C^*$- ternary algebras and of derivations on $C^*$-ternary algebras for the following Cauchy- Jensen functional equation…

Mathematical Physics · Physics 2011-01-04 Choonkil Park , John Michael Rassias , Won-Gil Park

In this paper, using the fixed point and direct methods, we prove the generalized Hyers-Ulam-Rassias stability of a Cauchy-Jensen additive functional equation in various normed spaces. The concept of Hyers-Ulam-Rassias stability originated…

Functional Analysis · Mathematics 2020-02-24 H. Azadi Kenary , Th. M. Rassias

Using the fixed point theorem we establish the Hyers-Ulam-Rassias stability of the generalized Pexider functional equation $$\frac{1}{\mid K\mid}\sum_{k\in K}f(x+k\cdot y)=g(x)+h(y),\;\;x,y\in E$$ from a normed space $E$ into a complete…

Functional Analysis · Mathematics 2014-06-17 E. Elqorachi , John M. Rassias , B. Bouikhalene

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

This paper investigates functional equations arising from perturbations of Cauchy differences. We study equations of the form \[ f(x+y)-f(x)-f(y)=B(x,y) \quad \text{or} \quad f(xy)-f(x)f(y) = B(x,y) \] where $B$ is a biadditive mapping, and…

Classical Analysis and ODEs · Mathematics 2026-03-23 Eszter Gselmann , Tomasz Małolepszy , Janusz Matkowski

Since the main work on Ulam-Hyers dependable stabilities of differential equations to date, numerous significant and applicable papers have been published, both in the sense of integer order and fractional order differential equations.…

Classical Analysis and ODEs · Mathematics 2019-08-16 J. Vanterler da C. Sousa , K. D. Kucche , E. Capelas de Oliveira

In this paper, We study the stability of solutions of fuzzy differential equations by Lyapunov's second method. By using scale equations and comparison principle for Lyapunov - like functions, we give some sufficient criterias for the…

Dynamical Systems · Mathematics 2007-05-23 Le Van Hien

We explore the Hyers-Ulam stability of perturbations for a homogeneous linear differential system with $2\times 2$ constant coefficient matrix. New necessary and sufficient conditions for the linear system to be Hyers-Ulam stable are…

Classical Analysis and ODEs · Mathematics 2022-03-25 Douglas R. Anderson , Masakazu Onitsuka

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

In this paper, we are dealing with the solution of the functional equation $$ \varphi\Big(\frac{x+y}2\Big)(f(x)-f(y))=F(x)-F(y), $$ concerning the unknown functions $\varphi,f$ and $F$ defined on a same open subinterval of the reals.…

Classical Analysis and ODEs · Mathematics 2020-11-23 Tibor Kiss , Zsolt Páles

In this paper, we introduce and solve the following additive-additive $(s,t)$-functional inequality \begin{eqnarray}\label{0.1} && \|g\left(x+y\right) -g(x) -g(y)\| +\| h(x+y) + h(x-y) -2 h(x) \| && \le \left\|s\left( 2…

Functional Analysis · Mathematics 2019-10-03 Choonkil Park

The main purpose of this paper is to determine the solution of generalized convex set-valued mappings satisfying certain functional equation. Some conclusions of stability of set-valued functional equations are obtained.

Functional Analysis · Mathematics 2020-10-13 Gang Lu , Yuanfeng Jin , Choonkil Park