Boundedness and Sobolev-Type Estimates for the Exponentially Damped Riesz Potential with Applications to the Regularity Theory of Elliptic PDEs

This paper investigates a new class of fractional integral operators, namely, the exponentially damped Riesz-type operators within the framework of variable exponent Lebesgue spaces <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><...

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Main Authors: Waqar Afzal, Mujahid Abbas, Jorge E. Macías-Díaz, Armando Gallegos, Yahya Almalki
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Fractal and Fractional
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Online Access:https://www.mdpi.com/2504-3110/9/7/458
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author Waqar Afzal
Mujahid Abbas
Jorge E. Macías-Díaz
Armando Gallegos
Yahya Almalki
author_facet Waqar Afzal
Mujahid Abbas
Jorge E. Macías-Díaz
Armando Gallegos
Yahya Almalki
author_sort Waqar Afzal
collection DOAJ
description This paper investigates a new class of fractional integral operators, namely, the exponentially damped Riesz-type operators within the framework of variable exponent Lebesgue spaces <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>L</mi><mrow><mi mathvariant="monospace">p</mi><mo>(</mo><mo>·</mo><mo>)</mo></mrow></msup></semantics></math></inline-formula>. To the best of our knowledge, the boundedness of such operators has not been addressed in any existing functional setting. We establish their boundedness under appropriate log-Hölder continuity and growth conditions on the exponent function <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="monospace">p</mi><mo>(</mo><mo>·</mo><mo>)</mo></mrow></semantics></math></inline-formula>. To highlight the novelty and practical relevance of the proposed operator, we conduct a comparative analysis demonstrating its effectiveness in addressing convergence, regularity, and stability of solutions to partial differential equations. We also provide non-trivial examples that illustrate not only these properties but also show that, under this operator, a broader class of functions becomes locally integrable. The exponential decay factor notably broadens the domain of boundedness compared to classical Riesz and Bessel–Riesz potentials, making the operator more versatile and robust. Additionally, we generalize earlier results on Sobolev-type inequalities previously studied in constant exponent spaces by extending them to the variable exponent setting through our fractional operator, which reduces to the classical Riesz potential when the decay parameter <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>λ</mo><mo>=</mo><mn>0</mn></mrow></semantics></math></inline-formula>. Applications to elliptic PDEs are provided to illustrate the functional impact of our results. Furthermore, we develop several new structural properties tailored to variable exponent frameworks, reinforcing the strength and applicability of the proposed theory.
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spelling doaj-art-cad20783c8c847b0b686eeaa52544b3c2025-08-20T03:58:26ZengMDPI AGFractal and Fractional2504-31102025-07-019745810.3390/fractalfract9070458Boundedness and Sobolev-Type Estimates for the Exponentially Damped Riesz Potential with Applications to the Regularity Theory of Elliptic PDEsWaqar Afzal0Mujahid Abbas1Jorge E. Macías-Díaz2Armando Gallegos3Yahya Almalki4Abdus Salam School of Mathematical Sciences, Government College University, 68-B, New Muslim Town, Lahore 54600, PakistanDepartment of Mechanical Engineering Sciences, Faculty of Engineering and the Built Environment, Doornfontein Campus, University of Johannesburg, Johannesburg 2092, South AfricaDepartment of Mathematics and Didactics of Mathematics, Tallinn University, 10120 Tallinn, EstoniaDepartamento de Ciencias Exactas y Tecnología, Centro Universitario de los Lagos, Universidad de Guadalajara, Enrique Díaz de León 1144, Colonia Paseos de la Montaña, Lagos de Moreno 47460, Jalisco, MexicoDepartment of Mathematics, College of Sciences, King Khalid University, Abha 61413, Saudi ArabiaThis paper investigates a new class of fractional integral operators, namely, the exponentially damped Riesz-type operators within the framework of variable exponent Lebesgue spaces <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>L</mi><mrow><mi mathvariant="monospace">p</mi><mo>(</mo><mo>·</mo><mo>)</mo></mrow></msup></semantics></math></inline-formula>. To the best of our knowledge, the boundedness of such operators has not been addressed in any existing functional setting. We establish their boundedness under appropriate log-Hölder continuity and growth conditions on the exponent function <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="monospace">p</mi><mo>(</mo><mo>·</mo><mo>)</mo></mrow></semantics></math></inline-formula>. To highlight the novelty and practical relevance of the proposed operator, we conduct a comparative analysis demonstrating its effectiveness in addressing convergence, regularity, and stability of solutions to partial differential equations. We also provide non-trivial examples that illustrate not only these properties but also show that, under this operator, a broader class of functions becomes locally integrable. The exponential decay factor notably broadens the domain of boundedness compared to classical Riesz and Bessel–Riesz potentials, making the operator more versatile and robust. Additionally, we generalize earlier results on Sobolev-type inequalities previously studied in constant exponent spaces by extending them to the variable exponent setting through our fractional operator, which reduces to the classical Riesz potential when the decay parameter <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>λ</mo><mo>=</mo><mn>0</mn></mrow></semantics></math></inline-formula>. Applications to elliptic PDEs are provided to illustrate the functional impact of our results. Furthermore, we develop several new structural properties tailored to variable exponent frameworks, reinforcing the strength and applicability of the proposed theory.https://www.mdpi.com/2504-3110/9/7/458Sobolev inequalityexponentially damped Riesz operatorHardy–Littlewood maximal operatorvariable Lebesgue spacesboundedness of fractional operatorsregularity of elliptic equations
spellingShingle Waqar Afzal
Mujahid Abbas
Jorge E. Macías-Díaz
Armando Gallegos
Yahya Almalki
Boundedness and Sobolev-Type Estimates for the Exponentially Damped Riesz Potential with Applications to the Regularity Theory of Elliptic PDEs
Fractal and Fractional
Sobolev inequality
exponentially damped Riesz operator
Hardy–Littlewood maximal operator
variable Lebesgue spaces
boundedness of fractional operators
regularity of elliptic equations
title Boundedness and Sobolev-Type Estimates for the Exponentially Damped Riesz Potential with Applications to the Regularity Theory of Elliptic PDEs
title_full Boundedness and Sobolev-Type Estimates for the Exponentially Damped Riesz Potential with Applications to the Regularity Theory of Elliptic PDEs
title_fullStr Boundedness and Sobolev-Type Estimates for the Exponentially Damped Riesz Potential with Applications to the Regularity Theory of Elliptic PDEs
title_full_unstemmed Boundedness and Sobolev-Type Estimates for the Exponentially Damped Riesz Potential with Applications to the Regularity Theory of Elliptic PDEs
title_short Boundedness and Sobolev-Type Estimates for the Exponentially Damped Riesz Potential with Applications to the Regularity Theory of Elliptic PDEs
title_sort boundedness and sobolev type estimates for the exponentially damped riesz potential with applications to the regularity theory of elliptic pdes
topic Sobolev inequality
exponentially damped Riesz operator
Hardy–Littlewood maximal operator
variable Lebesgue spaces
boundedness of fractional operators
regularity of elliptic equations
url https://www.mdpi.com/2504-3110/9/7/458
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