Perturbing polynomials with all their roots on the unit circle
نویسندگان
چکیده
منابع مشابه
Perturbing polynomials with all their roots on the unit circle
Given a monic real polynomial with all its roots on the unit circle, we ask to what extent one can perturb its middle coefficient and still have a polynomial with all its roots on the unit circle. We show that the set of possible perturbations forms a closed interval of length at most 4, with 4 achieved only for polynomials of the form x2n + cxn + 1 with c in [−2, 2]. The problem can also be fo...
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ژورنال
عنوان ژورنال: Mathematics of Computation
سال: 1998
ISSN: 0025-5718
DOI: 10.1090/s0025-5718-98-01007-2