Sharp decay estimates and numerical analysis for weakly coupled systems of two subdiffusion equations

Fuente: arXiv
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Main Authors: Li, Zhiyuan, Liu, Yikan, Wada, Kazuma
Format: Preprint
Published: 2025
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_version_ 1866917016382734336
author Li, Zhiyuan
Liu, Yikan
Wada, Kazuma
author_facet Li, Zhiyuan
Liu, Yikan
Wada, Kazuma
contents This paper investigates the initial-boundary value problem for weakly coupled systems of time-fractional subdiffusion equations with spatially and temporally varying coupling coefficients. By combining the energy method with the coercivity of fractional derivatives, we convert the original partial differential equations into a coupled ordinary differential system. Through Laplace transform and maximum principle arguments, we reveal a dichotomy in decay behavior: When the highest fractional order is less than one, solutions exhibit sublinear decay, whereas systems with the highest order equal to one demonstrate a distinct superlinear decay pattern. This phenomenon fundamentally distinguishes coupled systems from single fractional diffusion equations, where such accelerated superlinear decay never occurs. Numerical experiments employing finite difference methods and implicit discretization schemes validate the theoretical findings.
format Preprint
id arxiv_https___arxiv_org_abs_2504_18295
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sharp decay estimates and numerical analysis for weakly coupled systems of two subdiffusion equations
Li, Zhiyuan
Liu, Yikan
Wada, Kazuma
Analysis of PDEs
Numerical Analysis
35R11, 35K51, 35B40, 65M06
This paper investigates the initial-boundary value problem for weakly coupled systems of time-fractional subdiffusion equations with spatially and temporally varying coupling coefficients. By combining the energy method with the coercivity of fractional derivatives, we convert the original partial differential equations into a coupled ordinary differential system. Through Laplace transform and maximum principle arguments, we reveal a dichotomy in decay behavior: When the highest fractional order is less than one, solutions exhibit sublinear decay, whereas systems with the highest order equal to one demonstrate a distinct superlinear decay pattern. This phenomenon fundamentally distinguishes coupled systems from single fractional diffusion equations, where such accelerated superlinear decay never occurs. Numerical experiments employing finite difference methods and implicit discretization schemes validate the theoretical findings.
title Sharp decay estimates and numerical analysis for weakly coupled systems of two subdiffusion equations
topic Analysis of PDEs
Numerical Analysis
35R11, 35K51, 35B40, 65M06
url https://arxiv.org/abs/2504.18295