2006/11/27 by Franz Peherstorfer, F. Peherstorfer, Peherstorfer, F. +3
Mathematics · #Complex Variables (math.CV) #Differential Equations and Boundary Problems #Differential Equations and Numerical Methods #FOS: Mathematics #Spectral Theory (math.SP) #advanced mathematical theories #math.CV #math.SP
paper · pdf · doi:10.48550/arxiv.math/0611816
arxiv created 2006/11/27 · openalex publication_date 2006/11/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the correspondence between almost periodic difference operators and algebraic curves (spectral surfaces). An especial role plays the parametrization of the spectral curves in terms of, so called, branching divisors. The multiplication operator by the covering map with respect to the natural basis in the Hardy space on the surface is the 2d+1--diagonal matrix; the d--root of the product of the Green functions (counting their multiplicities) with respect to all infinite points on the surface is the symbol of the shift operator. We demonstrate an application of our general construction to a particular covering, which generate widely discussed almost periodic CMV matrices. We discuss an important theme: covering of one spectral surface by another one and related to this operation transformations on the set of multidiagonal operators (so called Renormalization Equations). We proof several new results dealing with Renormalization Equations for periodic Jacobi matrices (polynomial coverings) and the case of a rational double covering.