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JOURNALS // Zhurnal Vychislitel'noi Matematiki i Matematicheskoi Fiziki // Archive

Zh. Vychisl. Mat. Mat. Fiz., 2025 Volume 65, Number 12, Pages 2938–2958 (Mi zvmmf12115)

Papers published in the English version of the journal

The existence and stability of periodic solutions for right-end discontinuous singularly perturbed reaction-diffusion problems with multiple roots of degenerate equations

Mingkang Nia, Xin Shuaib

a School of Mathematical Sciences, Key Laboratory of Ministry of Education, Shanghai Key Laboratory of Pure Mathematics and Mathematical Practice, 200241, Shanghai, China
b School of Mathematical Sciences, East China Normal University, 200241, Shanghai, China

Abstract: In this paper, the Dirichlet periodic boundary value problem of a class of singularly perturbed reaction-diffusion equations with different degree roots for discontinuous nonlinear reaction terms is studied. By introducing the nonstandard boundary layer function method, the formal asymptotic solutions of the inner layer and boundary layer with fractional order form are constructed when the degenerate equation has multiple roots. The existence of periodic solutions is proved by using sufficiently accurate upper and lower solutions, and the asymptotic approximation accuracy is estimated. The asymptotic stability of formal asymptotic solutions in the sense of Lyapunov is further proved. Finally, a numerical example is given to demonstrate our results.

Key words: reaction-diffusion equation, double root, singular perturbation, boundary value problem, asymptotic theory.

Received: 27.11.2024
Revised: 03.09.2025
Accepted: 27.01.2026

Language: English


 English version:
Computational Mathematics and Mathematical Physics, 2025, 65:12, 2938–2958


© Steklov Math. Inst. of RAS, 2026