Electron. J. Differential Equations, Vol. 2026 (2026), No. 77, pp. 1-21.

Ground state solutions and asymptotics for discrete Kirchhoff problems

Mohammed Belahcen, Siham El Habib, Najib Tsouli

Abstract:
While superlinear discrete Kirchhoff problems have been extensively studied via variational minimax methods, the sublinear regime \(\sigma\in(1,2)\), where the Kirchhoff energy dominates the reaction term, remains essentially unexplored. Also the asymptotic behavior of ground states as \(\lambda\to0^+\) has not been investigated even in the continuous setting. We address this gap for the discrete Kirchhoff boundary value problem $$\displaylines{ -m\Big(\sum_{j=0}^{N}|\delta y_j|^2\Big)\Delta_d y_j =\lambda h_j(y_j), \quad j=1,\ldots,N,\cr y_0=y_{N+1}=0. }$$ Combining coercive minimization, constant-sign truncation, Krasnosel'skii genus theory, and scaling arguments, we establish existence of a nontrivial ground state for every \(\lambda >0\), two constant-sign solutions, and \(N\) pairs of nontrivial solutions under an evenness assumption. We further derive the sharp scaling \(\inf\mathcal J_\lambda\asymp-\lambda^{\frac{2}{2-\sigma}}\), show that normalized ground states converge to minimizers of an explicit limit functional, and obtain, to our knowledge, the first quantitative convergence rate for this class of problems. Newton-continuation computations confirm the predicted scaling exponents to high precision.

Submitted July 16, 2026. Published September 30, 2026.
Math Subject Classifications: 39A10, 35J60, 49J40.
Key Words: Asymptotic profile; convergence rate; discrete Kirchhoff problem; ground states; variational methods.
DOI: 10.58997/ejde.2026.77

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Mohammed Belahcen
Department of Mathematics
LAMAO Laboratory, Faculty of Sciences
Mohammed I University
60000 Oujda, Morocco
email: mohammed.belahcen.d24@ump.ac.ma
Siham El Habib
Department of Mathematics
LAMAO Laboratory, Faculty of Sciences
Mohammed I University
60000 Oujda, Morocco
email: s.elhabib@ump.ac.ma
Najib Tsouli
Department of Mathematics
LAMAO Laboratory, Faculty of Sciences
Mohammed I University
60000 Oujda, Morocco
email: n.tsouli@ump.ac.ma

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