Abstract
We establish necessary and sufficient conditions under which all minimal passive scattering systems that have a given transfer operator function are unitarily equivalent. These conditions can be significantly simplified in special cases important for applications, in particular, in the case where a transfer function is rational and in a more general case where this function is pseudoextendable.
Similar content being viewed by others
References
D. Z. Arov, “Passive linear stationary dynamic systems,” Sib. Mat. Zh., 20, No. 2, 211–228 (1979).
R. E. Kalman, P. L. Falb, and M. A. Arbib, Topics in Mathematical System Theory, McGraw-Hill, New York 1969.
D. Z. Arov, Linear Stationary Passive Systems with Losses [in Russian], Doctoral-Degree Thesis (Physics and Mathematics), Odessa (1985).
D. Z. Arov, “Stable dissipative linear stationary dynamic scattering systems,” J. Oper. Theory, 2, 95–126 (1979).
D. Z. Arov, M. A. Kaashoek, and D. R. Ric. “Minimal and optimal linear discrete time-invariant dissipative scattering systems,” Integr. Equal. Oper. Theory, 29, 127–154 (1997).
M. A. Nudel’man, “Optimal passive systems and semiboundedness of quadratic functionals,” Sib. Mat. Zh., 33, No. 1, 78–86 (1992).
B. Szökefalvi-Nagy and C. Foias, Harmonic Analysis of Operators in Hilbert Spaces [Russian translation] Mir, Moscow 1970.
S. S. Boiko and V. K. Dubovoi, “On some extremal problems connected with the suboperator of scattering through inner channels of a system,” Dop. Nats. Akad. Nauk Ukr., No. 4, 7–11 (1997).
M. S. Brodskii, “Unitary colligations and their characteristic functions,” Usp. Mat. Nauk, 33, No. 4 (202), 141–168 (1978).
R. K. Mohamed, Defect Functions and Regular Extensions of Holomorphic Contracting Matrix Functions [in Russian], Candidate-Degree Thesis (Physics and Mathematics), Kharkov (1996).
V. K. Dubovoi, B. Fritzsche, and B. Kirstein, “On spectrally associated Schur functions, Arov inner functions, and Nehari-type completion problem for Schur functions,” Integr. Equal. Oper. Theory, 17, 247–276 (1993).
V. K. Dubovoi and R. K. Mohamed, “Defect functions of holomorphic contracting functions, regular extensions, and open systems,” Math. Nachr., 160, 69–110 (1993).
V. M. Adamyan and D. Z. Arov, “On unitary couplings of semiunitary operators,” Mat. Issled., 1, No. 2, 3–66 (1966).
Yu. A. Rozanov, Stationary Random Processes [in Russian] Fizmatgiz, Moscow 1963.
I.I. Privalov, Boundary Values of Analytic Functions [in Russian] Gostekhteoretizdat, Moscow-Leningrad 1950.
D. Z. Arov and M. A. Nudel’man, “Passive linear stationary dynamical scattering systems with continuous time,” Integr. Equat. Oper. Theory, 24, No. 1, 1–45 (1996).
Rights and permissions
About this article
Cite this article
Arov, D.Z., Nudel’man, M.A. Criterion of unitary similarity of minimal passive scattering systems with a given transfer function. Ukr Math J 52, 161–172 (2000). https://doi.org/10.1007/BF02529631
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02529631