Periodic perturbations of unbounded Jacobi matrices II: Formulas for density

摘要

We give formulas for the density of the measure of orthogonality fororthonormal polynomials with unbounded recurrence coefficients. The formulasinvolve limits of appropriately scaled Tur\'an determinants or Christoffelfunctions. Exact asymptotics of the polynomials and numerical examples are alsoprovided.