Recieved: 01/09/2026
Accepted: 02/17/2026
Keywords: spectral problem, Sturm-Liouville equation
Available in the on-line version with: 24.07.2026
Kapustin N.Yu., Mammetsahedova S., Kholomeeva A.A. Problem for the Sturm–Liouville equation with the square of the spectral parameter in the boundary condition of the third kind. // Moscow University Journal. Series 15. Computational Mathematics and Cybernetics. 2026. N 2, p.36-42 https://doi.org/10.55959/MSU/0137–0782–15–2026–50–2–36–42.

In this paper, we study the spectral problem for the Sturm-Liouville equation. One of the boundary conditions is a homogeneous Dirichlet condition, and the other is a condition of the third kind, and contains the square of the spectral parameter. A biorthogonal system to the system of eigenfunctions of the task is constructed. The problems of the basis property and the Riesz basis property of system of eigenfunctions are investigated.