On the Existence of Solutions and Ulam-Type Stability for a Nonlinear <i>ψ</i>-Hilfer Fractional-Order Delay Integro-Differential Equation

In this work, we address a nonlinear <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential e...

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Main Authors: Cemil Tunç, Fehaid Salem Alshammari, Fahir Talay Akyıldız
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Fractal and Fractional
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Online Access:https://www.mdpi.com/2504-3110/9/7/409
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author Cemil Tunç
Fehaid Salem Alshammari
Fahir Talay Akyıldız
author_facet Cemil Tunç
Fehaid Salem Alshammari
Fahir Talay Akyıldız
author_sort Cemil Tunç
collection DOAJ
description In this work, we address a nonlinear <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential equation that incorporates <i>n</i>-multiple-variable time delays. Employing the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional derivative operator, we investigate the existence of a unique solution, as well as the Ulam–Hyers–Rassias stability, semi-Ulam–Hyers–Rassias stability, and Ulam–Hyers stability of the proposed <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential equation through the fixed-point approach. In this study, we enhance and generalize existing results in the literature on <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential equations, both including and excluding single delay, by establishing new findings for nonlinear <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential equations involving <i>n</i>-multiple-variable time delays. This study provides novel theoretical insights that deepen the qualitative understanding of fractional calculus.
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issn 2504-3110
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spelling doaj-art-aeeb2d11703145159d414cdc7b229b082025-08-20T02:45:42ZengMDPI AGFractal and Fractional2504-31102025-06-019740910.3390/fractalfract9070409On the Existence of Solutions and Ulam-Type Stability for a Nonlinear <i>ψ</i>-Hilfer Fractional-Order Delay Integro-Differential EquationCemil Tunç0Fehaid Salem Alshammari1Fahir Talay Akyıldız2Department of Mathematics, Faculty of Sciences, Van Yuzuncu Yıl University, 65080 Van, TurkeyDepartment of Mathematics and Statistics, Faculty of Sciences, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11564, Saudi ArabiaDepartment of Mathematics and Statistics, Faculty of Sciences, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11564, Saudi ArabiaIn this work, we address a nonlinear <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential equation that incorporates <i>n</i>-multiple-variable time delays. Employing the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional derivative operator, we investigate the existence of a unique solution, as well as the Ulam–Hyers–Rassias stability, semi-Ulam–Hyers–Rassias stability, and Ulam–Hyers stability of the proposed <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential equation through the fixed-point approach. In this study, we enhance and generalize existing results in the literature on <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential equations, both including and excluding single delay, by establishing new findings for nonlinear <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ψ</mi></semantics></math></inline-formula>-Hilfer fractional-order Volterra integro-differential equations involving <i>n</i>-multiple-variable time delays. This study provides novel theoretical insights that deepen the qualitative understanding of fractional calculus.https://www.mdpi.com/2504-3110/9/7/409ψ-Hilfer FrOVI-DEunique solutionUHR stabilitysemi-UHR stabilityUH stabilityfixed-point approach
spellingShingle Cemil Tunç
Fehaid Salem Alshammari
Fahir Talay Akyıldız
On the Existence of Solutions and Ulam-Type Stability for a Nonlinear <i>ψ</i>-Hilfer Fractional-Order Delay Integro-Differential Equation
Fractal and Fractional
ψ-Hilfer FrOVI-DE
unique solution
UHR stability
semi-UHR stability
UH stability
fixed-point approach
title On the Existence of Solutions and Ulam-Type Stability for a Nonlinear <i>ψ</i>-Hilfer Fractional-Order Delay Integro-Differential Equation
title_full On the Existence of Solutions and Ulam-Type Stability for a Nonlinear <i>ψ</i>-Hilfer Fractional-Order Delay Integro-Differential Equation
title_fullStr On the Existence of Solutions and Ulam-Type Stability for a Nonlinear <i>ψ</i>-Hilfer Fractional-Order Delay Integro-Differential Equation
title_full_unstemmed On the Existence of Solutions and Ulam-Type Stability for a Nonlinear <i>ψ</i>-Hilfer Fractional-Order Delay Integro-Differential Equation
title_short On the Existence of Solutions and Ulam-Type Stability for a Nonlinear <i>ψ</i>-Hilfer Fractional-Order Delay Integro-Differential Equation
title_sort on the existence of solutions and ulam type stability for a nonlinear i ψ i hilfer fractional order delay integro differential equation
topic ψ-Hilfer FrOVI-DE
unique solution
UHR stability
semi-UHR stability
UH stability
fixed-point approach
url https://www.mdpi.com/2504-3110/9/7/409
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AT fahirtalayakyıldız ontheexistenceofsolutionsandulamtypestabilityforanonlinearipsihilferfractionalorderdelayintegrodifferentialequation