3 papers
math.SP2026
On eigenvalues of self-adjoint extensions for defect larger than one
Annemarie Luger, Jakob Reiffenstein
Self-adjoint extensions of a symmetric operator are parametrised by Krein's formula, in which the -function interacts with another analytic function (the parameter). We obtain a…
math.SP2025
Nevanlinna matrix estimates without regularity conditions
Jakob Reiffenstein
The Nevanlinna matrix of a half-line Jacobi operator coincides, up to multiplication with a constant matrix, with the monodromy matrix of an associated canonical system. This canon…
math.SP2025
Growth estimates for Nevanlinna matrices of order larger than one half
Jakob Reiffenstein
Our objects of study are two-dimensional canonical systems that arise from indeterminate Hamburger moment problems and associated half-line Jacobi operators in limit circle case. T…