This book presents a comprehensive overview of the sum rule approach to
spectral analysis of orthogonal polynomials, which derives from Gábor
Szego's classic 1915 theorem and its 1920 extension. Barry Simon
emphasizes necessary and sufficient conditions, and provides
mathematical background that until now has been available only in
journals. Topics include background from the theory of meromorphic
functions on hyperelliptic surfaces and the study of covering maps of
the Riemann sphere with a finite number of slits removed. This allows
for the first book-length treatment of orthogonal polynomials for
measures supported on a finite number of intervals on the real line.
In addition to the Szego and Killip-Simon theorems for orthogonal
polynomials on the unit circle (OPUC) and orthogonal polynomials on the
real line (OPRL), Simon covers Toda lattices, the moment problem, and
Jacobi operators on the Bethe lattice. Recent work on applications of
universality of the CD kernel to obtain detailed asymptotics on the fine
structure of the zeros is also included. The book places special
emphasis on OPRL, which makes it the essential companion volume to the
author's earlier books on OPUC.