Inverse $t$-source problem and a strict positivity property for coupled subdiffusion systems

Fuente: arXiv
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Main Authors: BenSalah, Mohamed, Liu, Yikan
Format: Preprint
Published: 2026
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author BenSalah, Mohamed
Liu, Yikan
author_facet BenSalah, Mohamed
Liu, Yikan
contents This article is concerned with the inverse problem on determining the temporal component of the source term in a coupled system of time-fractional diffusion equations by single point observation. Under a non-degeneracy condition on the known spatial component, we establish the Lipschitz stability by observing all solution components by a series representation of the mild solution. To reduce the observation data, we prove the strict positivity of some fractional integral of the solution to the homogeneous problem by a modified Picard iteration. This, together with a coupled Duhamel's principle, lead us to the uniqueness of the inverse problem by observing any single solution component under a specific structural constraint on the unknown. Numerically, we propose an iterative regularizing ensemble Kalman method (IREKM) for the simultaneous recovery of the temporal sources. Through extensive numerical tests, we demonstrate its accuracy, robustness against noise, and scalability with respect to the number of components. Our findings highlight the essential roles of the non-degeneracy condition, measurement configuration, and fractional structural constraints in ensuring reliable reconstructions. The proposed framework provides both rigorous theoretical guarantees and a practical algorithmic approach for multi-component source identification in fractional diffusion systems.
format Preprint
id arxiv_https___arxiv_org_abs_2603_11700
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Inverse $t$-source problem and a strict positivity property for coupled subdiffusion systems
BenSalah, Mohamed
Liu, Yikan
Analysis of PDEs
Numerical Analysis
35R30, 35R11, 35B50, 65M32, 65C60
This article is concerned with the inverse problem on determining the temporal component of the source term in a coupled system of time-fractional diffusion equations by single point observation. Under a non-degeneracy condition on the known spatial component, we establish the Lipschitz stability by observing all solution components by a series representation of the mild solution. To reduce the observation data, we prove the strict positivity of some fractional integral of the solution to the homogeneous problem by a modified Picard iteration. This, together with a coupled Duhamel's principle, lead us to the uniqueness of the inverse problem by observing any single solution component under a specific structural constraint on the unknown. Numerically, we propose an iterative regularizing ensemble Kalman method (IREKM) for the simultaneous recovery of the temporal sources. Through extensive numerical tests, we demonstrate its accuracy, robustness against noise, and scalability with respect to the number of components. Our findings highlight the essential roles of the non-degeneracy condition, measurement configuration, and fractional structural constraints in ensuring reliable reconstructions. The proposed framework provides both rigorous theoretical guarantees and a practical algorithmic approach for multi-component source identification in fractional diffusion systems.
title Inverse $t$-source problem and a strict positivity property for coupled subdiffusion systems
topic Analysis of PDEs
Numerical Analysis
35R30, 35R11, 35B50, 65M32, 65C60
url https://arxiv.org/abs/2603.11700