Type: Article
Publication Date: 2003-07-01
Citations: 288
DOI: https://doi.org/10.4007/annals.2003.158.253
We discuss the proof of and systematic application of Case's sum rules for Jacobi matrices.Of special interest is a linear combination of two of his sum rules which has strictly positive terms.Among our results are a complete classification of the spectral measures of all Jacobi matrices J for which J -J 0 is Hilbert-Schmidt, and a proof of Nevai's conjecture that the Szegő condition holds if J -J 0 is trace class.