Direct and inverse problems for a periodic Jacobi matrix (Q1103175)

The author considers the inverse problem for a second order difference operator with periodic coefficients. He describes the form of the corresponding spectral function (matrix), and characterizes, in particular, all matrix functions which occur as spectral functions of such operators. These results may be considered as ``discrete analogue'' to the well-known Gel'fand-Levitan-Marchenko-theory on Sturm-Liouville operators.