3 papers
math.FA2019
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…
math.SP2018
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…
math.SP2018
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…