We consider the complex polynomial p: C → C defined by $$p(z)=\sum\limits_{i=0}^n{{p_i}{z^i}},{p_i}\in\mathbb{C}{\text{, }}i=0, . . . , n, {p_n}\ne 0.$$ (1) (9.1) The Fundamental Theorem of algebra asserts that this polynomial has n zeros counted by multiplicity. Finding these roots is a non trivial problem in numerical mathematics. Most algorithms deliver only approximations of the exact zeros without any or with only weak statements concerning the accuracy.