Improvement of convergence condition of the square-root interval method for multiple zeros

Miodrag S. Petković, Dušan M. Milošević

A new theorem concerned with the convergence of the Ostrowski-like method for the simultaneous inclusion of multiple complex zeros in circular complex arithmetic is established. Computationally verifiable initial condition that guarantees the convergence of this parallel inclusion method is significantly relaxed compared with the classical theorem stated in [Z. Angew. Math. Mech. 62 (1982), 627-630].