A Variant of D’Alembert’s Functional Equation on Semigroups with Endomorphisms

Let S be a semigroup, and let φ, ψ: S → S be two endomorphisms (which are not necessarily involutive). Our main goal in this paper is to solve the following generalized variant of d’Alembert’s functional equation f(xϕ(y))+f(ψ(y)x)=2f(x)f(y),      x,y ∈ S,f\left( {x\varphi \left( y \right)} \right) +...

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Main Authors: Akkaoui Ahmed, El Fatini Mohamed, Fadli Brahim
Format: Article
Language:English
Published: Sciendo 2022-03-01
Series:Annales Mathematicae Silesianae
Subjects:
Online Access:https://doi.org/10.2478/amsil-2022-0004
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author Akkaoui Ahmed
El Fatini Mohamed
Fadli Brahim
author_facet Akkaoui Ahmed
El Fatini Mohamed
Fadli Brahim
author_sort Akkaoui Ahmed
collection DOAJ
description Let S be a semigroup, and let φ, ψ: S → S be two endomorphisms (which are not necessarily involutive). Our main goal in this paper is to solve the following generalized variant of d’Alembert’s functional equation f(xϕ(y))+f(ψ(y)x)=2f(x)f(y),      x,y ∈ S,f\left( {x\varphi \left( y \right)} \right) + f\left( {\psi \left( y \right)x} \right) = 2f\left( x \right)f\left( y \right),\,\,\,\,\,\,x,y\, \in \,S, where f : S → ℂ is the unknown function by expressing its solutions in terms of multiplicative functions. Some consequences of this result are presented.
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spelling doaj.art-96738902d9d845bcacb5b9553bae9bc32022-12-22T01:10:45ZengSciendoAnnales Mathematicae Silesianae2391-42382022-03-0136111410.2478/amsil-2022-0004A Variant of D’Alembert’s Functional Equation on Semigroups with EndomorphismsAkkaoui Ahmed0El Fatini Mohamed1Fadli Brahim2Department of Mathematics, Faculty of Sciences, Ibn Tofail University, BP: 14000, Kenitra, MoroccoDepartment of Mathematics, Faculty of Sciences, Ibn Tofail University, BP: 14000, Kenitra, MoroccoDepartment of Mathematics, Faculty of Sciences, Chouaib Doukkali University, BP: 24000, El Jadida, MoroccoLet S be a semigroup, and let φ, ψ: S → S be two endomorphisms (which are not necessarily involutive). Our main goal in this paper is to solve the following generalized variant of d’Alembert’s functional equation f(xϕ(y))+f(ψ(y)x)=2f(x)f(y),      x,y ∈ S,f\left( {x\varphi \left( y \right)} \right) + f\left( {\psi \left( y \right)x} \right) = 2f\left( x \right)f\left( y \right),\,\,\,\,\,\,x,y\, \in \,S, where f : S → ℂ is the unknown function by expressing its solutions in terms of multiplicative functions. Some consequences of this result are presented.https://doi.org/10.2478/amsil-2022-0004functional equationd’alembertsemigroupmultiplicative functionendomorphism39b52
spellingShingle Akkaoui Ahmed
El Fatini Mohamed
Fadli Brahim
A Variant of D’Alembert’s Functional Equation on Semigroups with Endomorphisms
Annales Mathematicae Silesianae
functional equation
d’alembert
semigroup
multiplicative function
endomorphism
39b52
title A Variant of D’Alembert’s Functional Equation on Semigroups with Endomorphisms
title_full A Variant of D’Alembert’s Functional Equation on Semigroups with Endomorphisms
title_fullStr A Variant of D’Alembert’s Functional Equation on Semigroups with Endomorphisms
title_full_unstemmed A Variant of D’Alembert’s Functional Equation on Semigroups with Endomorphisms
title_short A Variant of D’Alembert’s Functional Equation on Semigroups with Endomorphisms
title_sort variant of d alembert s functional equation on semigroups with endomorphisms
topic functional equation
d’alembert
semigroup
multiplicative function
endomorphism
39b52
url https://doi.org/10.2478/amsil-2022-0004
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