Properties of iteration of Toeplitz operators with Toeplitz preconditioners (Q1267027)

Toeplitz operators are preconditioned by approximations applied to the symbol (also known as generating function) of the operator. The preconditioned operator divides in two parts, a compact one and a perturbation. As a result, Krylov subspace methods exhibit superconvergence in initial iterations. Convergence estimates are given in terms of the symbol of the operator. The results are confirmed by numerical experiments.