Characteristic Functions, Scattering Functions and Transfer Functions

Transfer functions and characteristic functions proved to be key in operator theory and system theory. Moshe Livic played a major role in developing these functions, and this book of papers dedicated to his memory covers a wide variety of topics in the field.

Daniel Alpay and Victor Vinnikov During the period July 9 to July 13, 2007,a conference called Characteristic fu- tions and transfer functions in operator theory and system theory: a conference dedicated to PaulFuhrmann onhis 70thanniversary and to the memory ofMoshe Livsiconhis90thanniversarywasheldattheDepartmentofMathematicsofBen GurionUniversityoftheNegev.Thenotionsoftransferfunctionandcharacteristic functions proved to be fundamental in the last ?fty years in operator theory and in system theory. This conference was envisaged to pay tribute to our colleagues PaulFuhrmannandMosheLivsicwhoplayedacentralroleindevelopingthese- tions. Sadly, Moshe Livsic passedawayon the 30thof March,2007(11th of Nissan 5767), so the conference was dedicated to his memory. It is a pleasure to thank all the participants, who contributed to a very exciting and fruitful conference, and especially those who submitted papers to the present volume. The volume contains a selection of thirteen research papers dedicated to the memory of Moshe Livsic. The topics addressed can be divided into the following categories: Classical operator theory and its applications: This pertains to the paper Diff- ential-di?erence equations in entire functions by G. Belitskii and V. Tkachenko, the paper Bi-Isometries and Commutant Lifting by H. Bercovici, R.G. Douglas. and C. Foias and the paper Convexity of ranges and connectedness of level sets of quadratic forms by I. Feldman, N. Krupnik and A. Markus. Ergodictheoryandstochasticprocesses: We have the papersTheone-sidedergodic Hilbert transform of normal contractions by G. Cohen and M. Lin, and Integral Equations in the Theory of Levy Processes by L. Sakhnovich. Geometryofsmoothmappings:This iscoveredbythepaper ofY.Yomdinentitled ?-Spread of sets in metric spaces and critical values of smooth functions.

Volume in memory of Moshe Livsic, first class mathematician who, in particular, introduced the notion of characteristic operator function and of transfer function Includes supplementary material: sn.pub/extras

Texte du rabat

The notions of transfer function and characteristic functions proved to be fundamental in the last fifty years in operator theory and in system theory. Moshe Livsic played a central role in developing these notions, and the book contains a selection of carefully chosen refereed papers dedicated to his memory. Topics include classical operator theory, ergodic theory and stochastic processes, geometry of smooth mappings, mathematical physics, Schur analysis and system theory. The variety of topics attests well to the breadth of Moshe Livsic's mathematical vision and the deep impact of his work. The book will appeal to researchers in mathematics, electrical engineering and physics.

Contenu
Differential-difference Equations in Entire Functions.- Inverse Stieltjes-like Functions and Inverse Problems for Systems with Schrödinger Operator.- Bi-Isometries and Commutant Lifting.- The One-sided Ergodic Hilbert Transform of Normal Contractions.- Model Reduction in Symbolically Semi-separable Systems with Application to Pre-conditioners for 3D Sparse Systems of Equations.- Pick Matrices for Schur Multipliers.- The Stable Rank of a Nest Algebra and Strong Stabilization of Linear Time-varying Systems.- Convexity of Ranges and Connectedness of Level Sets of Quadratic Forms.- The Schur Algorithm in Terms of System Realizations.- On Some Interrelations Between J-Potapov Functions and J-Potapov Sequences.- A Solvable Model for Scattering on a Junction and a Modified Analytic Perturbation Procedure.- Integral Equations in the Theory of Levy Processes.- ?-spread of Sets in Metric Spaces and Critical Values of Smooth Functions.