{ "id": "1909.05532", "version": "v1", "published": "2019-09-12T09:34:19.000Z", "updated": "2019-09-12T09:34:19.000Z", "title": "Moduli of roots of hyperbolic polynomials and Descartes' rule of signs", "authors": [ "Vladimir Petrov Kostov" ], "categories": [ "math.CA" ], "abstract": "A real univariate polynomial with all roots real is called hyperbolic. By Descartes' rule of signs for hyperbolic polynomials (HPs) with all coefficients nonvanishing, a HP with $c$ sign changes and $p$ sign preservations in the sequence of its coefficients has exactly $c$ positive and $p$ negative roots. For $c=2$ and for degree $6$ HPs, we discuss the question: When the moduli of the $6$ roots of a HP are arranged in the increasing order on the real half-line, at which positions can be the moduli of its two positive roots depending on the positions of the two sign changes in the sequence of coefficients?", "revisions": [ { "version": "v1", "updated": "2019-09-12T09:34:19.000Z" } ], "analyses": { "keywords": [ "hyperbolic polynomials", "sign changes", "real univariate polynomial", "coefficients", "sign preservations" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }