1303.4161 (Milivoje Lukic)

Square-summable variation and absolutely continuous spectrum    [PDF]

Milivoje Lukic

Recent results of Denisov and Kaluzhny-Shamis describe the absolutely continuous spectrum of Jacobi matrices with coefficients that obey an l^2 bounded variation condition with step p and are asymptotically periodic. We extend these results to CMV matrices. We also replace the asymptotic periodicity condition by the weaker condition of convergence to an isospectral torus and, for small p, we remove even that condition.

View original: http://arxiv.org/abs/1303.4161