8 citations · 41 across the 10 of their papers we have counts for
10 papers
On the inversion of the block double-structured and of the triple-structured Toeplitz matrices and on the corresponding reflection coefficients
Inna Roitberg, Alexander Sakhnovich
The results on the inversion of convolution operators as well as Toeplitz (and block Toeplitz) matrices in the -D (one-dimensional) case are classical and have numerous applicat…
Arov--Krein entropy functionals and indefinite interpolation problems
I. Roitberg, A. L. Sakhnovich
We generalize the notion of the Arov-Krein entropy functional for the case of generalized Nevanlinna functions and obtain a representation of these functionals on solutions of inde…
Discrete Dirac systems on the semiaxis: rational reflection coefficients and Weyl functions
B. Fritzsche, B. Kirstein, I. Ya. Roitberg +1
We consider the cases of the self-adjoint and skew-self-adjoint discrete Dirac systems, obtain explicit expressions for reflection coefficients and show that rational reflection co…
General-type discrete self-adjoint Dirac systems: explicit solutions of direct and inverse problems, asymptotics of Verblunsky-type coefficients and stability of solving inverse problem
I. Ya. Roitberg, A. L. Sakhnovich
We consider discrete self-adjoint Dirac systems determined by the potentials (sequences) such that the matrices are positive definite and -unitary, where is…
Skew-selfadjoint Dirac systems: stability of the procedure of explicit solving the inverse problem
B. Fritzsche, B. Kirstein, I. Ya. Roitberg +1
Procedures to recover explicitly discrete and continuous skew-selfadjoint Dirac systems on semi-axis from rational Weyl matrix functions are considered. Their stability is shown. S…
Pseudo-Exponential-Type Solutions of Wave Equations Depending on Several Variables
Bernd Fritzsche, Bernd Kirstein, Inna Ya. Roitberg +1
Using matrix identities, we construct explicit pseudo-exponential-type solutions of linear Dirac, Loewner and Schrödinger equations depending on two variables and of nonlinear wave…
Skew-self-adjoint Dirac systems with a rectangular matrix potential: Weyl theory, direct and inverse problems
B. Fritzsche, B. Kirstein, I. Ya. Roitberg +1
A non-classical Weyl theory is developed for skew-self-adjoint Dirac systems with rectangular matrix potentials. The notion of the Weyl function is introduced and direct and invers…
Recovery of Dirac system from the rectangular Weyl matrix function
B. Fritzsche, B. Kirstein, I. Ya. Roitberg +1
Weyl theory for Dirac systems with rectangular matrix potentials is non-classical. The corresponding Weyl functions are rectangular matrix functions. Furthermore, they are non-expa…
Weyl theory and explicit solutions of direct and inverse problems for a Dirac system with rectangular matrix potential
B. Fritzsche, B. Kirstein, I. Ya. Roitberg +1
A non-classical Weyl theory is developed for Dirac systems with rectangular matrix potentials. The notion of the Weyl function is introduced and the corresponding direct problem is…
Weyl matrix functions and inverse problems for discrete Dirac type self-adjoint system: explicit and general solutions
B. Fritzsche, B. Kirstein, I. Ya. Roitberg +1
Discrete Dirac type self-adjoint system is equivalent to the block Szegö recurrence. Representation of the fundamental solution is obtained, inverse problems on the interval and se…