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JOURNALS // Sibirskii Zhurnal Industrial'noi Matematiki // Archive

Sib. Zh. Ind. Mat., 2024 Volume 27, Number 2, Pages 121–132 (Mi sjim1285)

Upper bounds for the eigenvalue multiplicities of a fourth-order differential operator on a graph

A. A. Urtaeva

Khetagurov North Ossetian State University, Vladikavkaz, 362025 Russia

Abstract: The paper studies a model of a planar beam structure described by a fourth-order boundary value problem on a geometric graph. Elastic-hinge joint conditions are posed at the interior vertices of the graph. We study the properties of the spectral points of the corresponding spectral problem, prove upper bounds for the eigenvalue multiplicities, and show that the eigenvalue multiplicities depend on the graph structure (the number of boundary vertices, cycles, etc.). We give an example showing that our estimates are sharp.

Keywords: beam equation, quantum graph, eigenvalue, multiplicity.

UDC: 517.927.25

Received: 05.12.2023
Revised: 11.03.2024
Accepted: 17.04.2024

DOI: 10.33048/SIBJIM.2024.27.209


 English version:
Journal of Applied and Industrial Mathematics, 2024, 18:2, 352–360


© Steklov Math. Inst. of RAS, 2026