An Inverse Problem for a Non-Homogeneous Time-Space Fractional Equation

We consider the inverse problem of finding the solution of a generalized time-space fractional equation and the source term knowing the spatial mean of the solution at any times <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><sema...

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Main Authors: Abdallah El Hamidi, Mokhtar Kirane, Ali Tfayli
Format: Article
Language:English
Published: MDPI AG 2022-07-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/10/15/2586
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author Abdallah El Hamidi
Mokhtar Kirane
Ali Tfayli
author_facet Abdallah El Hamidi
Mokhtar Kirane
Ali Tfayli
author_sort Abdallah El Hamidi
collection DOAJ
description We consider the inverse problem of finding the solution of a generalized time-space fractional equation and the source term knowing the spatial mean of the solution at any times <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>t</mi><mo>∈</mo><mo>(</mo><mn>0</mn><mo>,</mo><mi>T</mi><mo>]</mo><mo>,</mo></mrow></semantics></math></inline-formula> as well as the initial and the boundary conditions. The existence and the continuity with respect to the data of the solution for the direct and the inverse problem are proven by Fourier’s method and the Schauder fixed-point theorem in an adequate convex bounded subset. In the published articles on this topic, the incorrect use of the estimates in the generalized Mittag–Leffler functions is commonly performed. This leads to false proofs of the Fourier series’ convergence to recover the equation satisfied by the solution, the initial data or the boundary conditions. In the present work, the correct framework to recover the decay of fractional Fourier coefficients is established; this allows one to recover correctly the initial data, the boundary conditions and the partial differential equations within the space-time domain.
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spelling doaj.art-8253b06883f349e5974e6d271c1f6cff2023-11-30T22:37:28ZengMDPI AGMathematics2227-73902022-07-011015258610.3390/math10152586An Inverse Problem for a Non-Homogeneous Time-Space Fractional EquationAbdallah El Hamidi0Mokhtar Kirane1Ali Tfayli2Laboratoire LaSIE, La Rochelle Université, 17042 La Rochelle, France Department of Mathematics, Khalifa University of Science and Technology, Abu Dhabi P.O. Box 127788, United Arab EmiratesLaboratoire LaSIE, La Rochelle Université, 17042 La Rochelle, FranceWe consider the inverse problem of finding the solution of a generalized time-space fractional equation and the source term knowing the spatial mean of the solution at any times <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>t</mi><mo>∈</mo><mo>(</mo><mn>0</mn><mo>,</mo><mi>T</mi><mo>]</mo><mo>,</mo></mrow></semantics></math></inline-formula> as well as the initial and the boundary conditions. The existence and the continuity with respect to the data of the solution for the direct and the inverse problem are proven by Fourier’s method and the Schauder fixed-point theorem in an adequate convex bounded subset. In the published articles on this topic, the incorrect use of the estimates in the generalized Mittag–Leffler functions is commonly performed. This leads to false proofs of the Fourier series’ convergence to recover the equation satisfied by the solution, the initial data or the boundary conditions. In the present work, the correct framework to recover the decay of fractional Fourier coefficients is established; this allows one to recover correctly the initial data, the boundary conditions and the partial differential equations within the space-time domain.https://www.mdpi.com/2227-7390/10/15/2586inverse problemfractional derivativetime-space fractional equationintegral equationsbiorthogonal system of functionsFourier series
spellingShingle Abdallah El Hamidi
Mokhtar Kirane
Ali Tfayli
An Inverse Problem for a Non-Homogeneous Time-Space Fractional Equation
Mathematics
inverse problem
fractional derivative
time-space fractional equation
integral equations
biorthogonal system of functions
Fourier series
title An Inverse Problem for a Non-Homogeneous Time-Space Fractional Equation
title_full An Inverse Problem for a Non-Homogeneous Time-Space Fractional Equation
title_fullStr An Inverse Problem for a Non-Homogeneous Time-Space Fractional Equation
title_full_unstemmed An Inverse Problem for a Non-Homogeneous Time-Space Fractional Equation
title_short An Inverse Problem for a Non-Homogeneous Time-Space Fractional Equation
title_sort inverse problem for a non homogeneous time space fractional equation
topic inverse problem
fractional derivative
time-space fractional equation
integral equations
biorthogonal system of functions
Fourier series
url https://www.mdpi.com/2227-7390/10/15/2586
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