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arXiv · 2109.07182

The disconnectedness of certain sets defined after uni-variate polynomials

Vladimir Petrov Kostov
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Abstract

We consider the set of monic real univariate polynomials of a given degree $d$ with non-vanishing coefficients, with given signs of the coefficients and with given quantities $pos$ of their positive and $neg$ of their negative roots (all roots are distinct). For $d=6$ and for signs of the coefficients $(+,-,+,+,+,-,+)$, we prove that the set of such polynomials having two positive, two negative and two complex conjugate roots, is not connected. For $pos+neg\leq 3$ and for any $d$, we give the exhaustive answer to the question for which signs of the coefficients there exist polynomials with such values of $pos$ and $neg$.

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Vladimir Petrov Kostov. 2021-09-15. The disconnectedness of certain sets defined after uni-variate polynomials. https://arxiv.org/abs/2109.07182

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