In this work we give su±cient conditions for k-th approximations of the polynomial roots of f(x) when the Maehly{Aberth{Ehrlich,
Werner-Borsch-Supan, Tanabe, Improved Borsch-Supan iteration methods
fail on the next step. For these methods all non-attractive sets are found. This
is a subsequent improvement of previously developed techniques and known
facts. The users of these methods can use the results presented here for
software implementation in Distributed Applications and Simulation Environ-
ments. Numerical examples with graphics are shown.
