In complex analysis, the pseudo-zero set or root neighborhood of a degree-m polynomial p(z) is the set of all complex numbers that are roots of polynomials whose coefficients differ from p's by a small amount. Namely, given a norm |·| on , the pseudo-zero set is the set of all zeros of degree-m polynomials q such that |p-q| (as vectors) is less than a given ε.
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