5 citations · 45 across the 42 of their papers we have counts for
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-triangular operators: spectral properties and important examples
Lev Sakhnovich
We introduce a notion of -triangular operators in the Hilbert space using some basic ideas from triangular representation theory. Our notion generalizes the well-known notio…
Infinite Hankel Block Matrices, Extremal Problems
Lev Sakhnovich
In this paper we use the matrix analogue of eigenvalue to formulate and to solve the extremal Nehary problem. When is a scalar, our approach coincides with…
Matrix-Valued Generalizations of the Theorems of Borg and Hochstadt
E. D. Belokolos, F. Gesztesy, K. A. Makarov +1
We prove a generalization of the well-known theorems by Borg and Hochstadt for periodic self-adjoint Schrödinger operators without a spectral gap, respectively, one gap in their sp…
A Class of Matrix-Valued Schrödinger Operators with Prescribed Finite-Band Spectra
Fritz Gesztesy, Lev A. Sakhnovich
We construct a class of matrix-valued Schrödinger operators with prescribed finite-band spectra of maximum spectral multiplicity. The corresponding matrix potentials are shown to b…