M(λ) theory for singular Hamiltonian systems with one singular point
SIAM Journal on Mathematical Analysis
Recovery of the m-function from spectral data for generalized Sturm-Liouville problems
Journal of Computational and Applied Mathematics - Special issue: On the occasion of the eightieth birthday of prof. W.M. Everitt
Eigenvalue asymptotics for differential operators on graphs
Journal of Computational and Applied Mathematics
Hi-index | 7.29 |
We consider a system formulation for Sturm-Liouville operators with formally self-adjoint boundary conditions on a graph. An M-matrix associated with the boundary value problem is defined and related to the matrix Prufer angle associated with the system boundary value problem, and consequently with the boundary value problem on the graph. Asymptotics for the M-matrix are obtained as the eigenparameter tends to negative infinity. We show that the boundary conditions may be recovered, up to a unitary equivalence, from the M-matrix and that the M-matrix is a Herglotz function. This is the first in a series of papers devoted to the reconstruction of the Sturm-Liouville problem on a graph from its M-matrix.